/* ===== CSS Custom Properties & Design Tokens ===== */
:root {
    /* Colors - Light Theme */
    --bg-primary: #f8fafc;
    --bg-secondary: #ffffff;
    --bg-card: rgba(255, 255, 255, 0.9);
    --bg-card-hover: rgba(241, 245, 249, 0.95);
    --bg-input: rgba(0, 0, 0, 0.04);
    --bg-input-focus: rgba(0, 0, 0, 0.08);

    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #64748b;
    --text-accent: #6366f1;

    --accent-1: #4f46e5;
    --accent-2: #9333ea;
    --accent-3: #7c3aed;
    --accent-gradient: linear-gradient(135deg, #4f46e5 0%, #9333ea 50%, #db2777 100%);
    --accent-gradient-subtle: linear-gradient(135deg, rgba(79, 70, 229, 0.1) 0%, rgba(147, 51, 234, 0.1) 100%);
    --accent-gradient-2: linear-gradient(135deg, #4f46e5 0%, #7c3aed 100%);

    --border-color: rgba(0, 0, 0, 0.08);
    --border-active: rgba(79, 70, 229, 0.4);

    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 10px 32px rgba(0, 0, 0, 0.1);
    --shadow-glow: 0 0 40px rgba(79, 70, 229, 0.15);
    --shadow-glow-strong: 0 0 60px rgba(79, 70, 229, 0.25);

    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 28px;
    --radius-full: 9999px;

    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-xs: 0.75rem;
    --font-sm: 0.875rem;
    --font-base: 1rem;
    --font-lg: 1.125rem;
    --font-xl: 1.5rem;
    --font-2xl: 2rem;
    --font-3xl: 2.75rem;
    --font-4xl: 3.5rem;

    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;
    --space-4xl: 6rem;

    /* Transitions */
    --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
    --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
    --duration-fast: 150ms;
    --duration-normal: 250ms;
    --duration-slow: 400ms;
}

/* ===== Reset & Base ===== */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-family);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
    position: relative;
}

body.menu-open {
    overflow: hidden;
}

a {
    color: var(--text-accent);
    text-decoration: none;
    transition: color var(--duration-normal) var(--ease-out);
}

a:hover {
    color: var(--accent-2);
}

ul,
ol {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

/* ===== Background Particles ===== */
.bg-particles {
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: 0;
    overflow: hidden;
}

.particle {
    position: absolute;
    border-radius: 50%;
    background: var(--accent-gradient);
    opacity: 0.03;
    animation: floatParticle 20s infinite ease-in-out;
}

.particle:nth-child(1) {
    width: 600px;
    height: 600px;
    top: -200px;
    left: -100px;
    animation-delay: 0s;
    animation-duration: 25s;
}

.particle:nth-child(2) {
    width: 400px;
    height: 400px;
    top: 50%;
    right: -150px;
    animation-delay: -5s;
    animation-duration: 20s;
}

.particle:nth-child(3) {
    width: 300px;
    height: 300px;
    bottom: -100px;
    left: 30%;
    animation-delay: -10s;
    animation-duration: 22s;
}

.particle:nth-child(4) {
    width: 200px;
    height: 200px;
    top: 30%;
    left: 60%;
    animation-delay: -3s;
    animation-duration: 18s;
    opacity: 0.05;
}

.particle:nth-child(5) {
    width: 500px;
    height: 500px;
    bottom: 10%;
    right: 20%;
    animation-delay: -8s;
    animation-duration: 28s;
    opacity: 0.02;
}

.particle:nth-child(6) {
    width: 150px;
    height: 150px;
    top: 10%;
    left: 40%;
    animation-delay: -12s;
    animation-duration: 16s;
    opacity: 0.06;
}

@keyframes floatParticle {

    0%,
    100% {
        transform: translate(0, 0) scale(1);
    }

    25% {
        transform: translate(30px, -40px) scale(1.05);
    }

    50% {
        transform: translate(-20px, 20px) scale(0.95);
    }

    75% {
        transform: translate(40px, 30px) scale(1.02);
    }
}

/* ===== Container ===== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
    position: relative;
    z-index: 1;
}

.container--narrow {
    max-width: 960px;
}

.container--medium {
    max-width: 900px;
}

/* ===== Header / Navigation ===== */
.site-header {
    padding: 0;
    border-bottom: 1px solid var(--border-color);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    position: sticky;
    top: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.85);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-md) 0;
    max-width: 1200px;
    margin: 0 auto;
    padding-left: var(--space-lg);
    padding-right: var(--space-lg);
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    text-decoration: none;
    color: var(--text-primary);
    flex-shrink: 0;
}

.logo-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    background: var(--accent-gradient-subtle);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-active);
    transition: transform var(--duration-normal) var(--ease-spring);
}

.logo:hover .logo-icon {
    transform: rotate(-5deg) scale(1.05);
}

.logo-text {
    font-size: var(--font-lg);
    font-weight: 700;
    letter-spacing: -0.02em;
    color: var(--text-primary);
}

.logo-accent {
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Desktop Navigation */
.desktop-nav {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
}

.nav-link {
    padding: 10px 18px;
    border-radius: var(--radius-full);
    font-size: var(--font-sm);
    font-weight: 500;
    color: var(--text-secondary);
    text-decoration: none;
    transition: all var(--duration-normal) var(--ease-out);
    white-space: nowrap;
}

.nav-link:hover {
    color: var(--text-primary);
    background: rgba(255, 255, 255, 0.05);
}

.nav-link.active {
    color: var(--text-primary);
    background: var(--accent-gradient-subtle);
    border: 1px solid rgba(99, 102, 241, 0.2);
}

/* Hamburger Button */
.hamburger {
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    width: 44px;
    height: 44px;
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    cursor: pointer;
    gap: 5px;
    transition: all var(--duration-normal) var(--ease-out);
    z-index: 1001;
}

.hamburger:hover {
    border-color: var(--border-active);
    background: rgba(99, 102, 241, 0.08);
}

.hamburger-line {
    width: 20px;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: all var(--duration-normal) var(--ease-out);
    transform-origin: center;
}

.hamburger[aria-expanded="true"] .hamburger-line:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.hamburger[aria-expanded="true"] .hamburger-line:nth-child(2) {
    opacity: 0;
    transform: scaleX(0);
}

.hamburger[aria-expanded="true"] .hamburger-line:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* Mobile Navigation Overlay */
.mobile-nav-overlay {
    position: fixed;
    inset: 0;
    background: rgba(10, 10, 26, 0.95);
    backdrop-filter: blur(30px);
    -webkit-backdrop-filter: blur(30px);
    z-index: 999;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    opacity: 0;
    visibility: hidden;
    transition: all var(--duration-slow) var(--ease-out);
}

.mobile-nav-overlay[aria-hidden="false"] {
    opacity: 1;
    visibility: visible;
}

.mobile-nav-link {
    font-size: var(--font-xl);
    font-weight: 600;
    color: var(--text-secondary);
    text-decoration: none;
    padding: var(--space-md) var(--space-xl);
    border-radius: var(--radius-lg);
    transition: all var(--duration-normal) var(--ease-out);
    transform: translateY(20px);
    opacity: 0;
}

.mobile-nav-overlay[aria-hidden="false"] .mobile-nav-link {
    transform: translateY(0);
    opacity: 1;
}

.mobile-nav-link:nth-child(1) {
    transition-delay: 0.05s;
}

.mobile-nav-link:nth-child(2) {
    transition-delay: 0.1s;
}

.mobile-nav-link:nth-child(3) {
    transition-delay: 0.15s;
}

.mobile-nav-link:nth-child(4) {
    transition-delay: 0.2s;
}

.mobile-nav-link:nth-child(5) {
    transition-delay: 0.25s;
}

.mobile-nav-link:nth-child(6) {
    transition-delay: 0.3s;
}

.mobile-nav-link:hover,
.mobile-nav-link.active {
    color: var(--text-primary);
    background: var(--accent-gradient-subtle);
}

/* ===== Hero Section ===== */
.hero {
    text-align: center;
    padding: var(--space-2xl) 0 var(--space-xl);
    animation: fadeInUp 0.8s var(--ease-out) both;
}

.hero h1 {
    font-size: var(--font-4xl);
    font-weight: 800;
    letter-spacing: -0.03em;
    line-height: 1.1;
    margin-bottom: var(--space-md);
}

.gradient-text {
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: var(--font-lg);
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
    line-height: 1.7;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-lg);
    border-radius: var(--radius-full);
    background: var(--accent-gradient-subtle);
    border: 1px solid rgba(99, 102, 241, 0.2);
    font-size: var(--font-sm);
    color: var(--text-accent);
    font-weight: 500;
    margin-bottom: var(--space-xl);
    animation: fadeInUp 0.6s var(--ease-out) 0.1s both;
}

/* ===== Converter Card ===== */
.converter-card {
    background: var(--bg-card);
    backdrop-filter: blur(40px);
    -webkit-backdrop-filter: blur(40px);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border-color);
    padding: var(--space-2xl);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
    animation: fadeInUp 0.8s var(--ease-out) 0.1s both;
    transition: box-shadow var(--duration-slow) var(--ease-out);
}

.converter-card:hover {
    box-shadow: var(--shadow-lg), var(--shadow-glow-strong);
}

/* ===== Category Selector ===== */
.section-label {
    font-size: var(--font-sm);
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    font-weight: 600;
    margin-bottom: var(--space-md);
}

.category-options {
    display: flex;
    gap: var(--space-sm);
    flex-wrap: wrap;
}

.category-pill {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-lg);
    border-radius: var(--radius-full);
    border: 1px solid var(--border-color);
    background: var(--bg-input);
    cursor: pointer;
    transition: all var(--duration-normal) var(--ease-out);
    font-size: var(--font-sm);
    color: var(--text-secondary);
    user-select: none;
}

.category-pill input[type="radio"] {
    position: absolute;
    opacity: 0;
    pointer-events: none;
}

.category-pill:hover {
    border-color: var(--border-active);
    background: rgba(99, 102, 241, 0.08);
    color: var(--text-primary);
}

.category-pill.active {
    background: var(--accent-gradient-subtle);
    border-color: var(--accent-1);
    color: var(--text-primary);
    box-shadow: 0 0 20px rgba(99, 102, 241, 0.15);
}

.category-pill.active .pill-text {
    font-weight: 600;
}

.pill-icon {
    font-size: var(--font-lg);
    line-height: 1;
}

.pill-text small {
    color: var(--text-muted);
    font-weight: 400;
}

/* ===== Divider ===== */
.divider {
    height: 1px;
    background: var(--border-color);
    margin: var(--space-xl) 0;
}

/* ===== Input Fields ===== */
.fields-grid {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.input-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    align-items: center;
    gap: var(--space-lg);
    padding: var(--space-sm) 0;
    animation: fadeInUp 0.4s var(--ease-out) both;
}

.input-row.hidden {
    display: none;
}

.field-label {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-size: var(--font-base);
    font-weight: 500;
    color: var(--text-primary);
    white-space: nowrap;
}

.flag-icon {
    font-size: var(--font-xl);
    line-height: 1;
}

.input-wrapper {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.size-input {
    flex: 1;
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 12px 16px;
    color: var(--text-primary);
    font-family: var(--font-family);
    font-size: var(--font-base);
    font-weight: 500;
    outline: none;
    transition: all var(--duration-normal) var(--ease-out);
    width: 100%;
    -moz-appearance: textfield;
}

.size-input::-webkit-outer-spin-button,
.size-input::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

.size-input::placeholder {
    color: var(--text-muted);
    font-weight: 400;
}

.size-input:focus {
    background: var(--bg-input-focus);
    border-color: var(--accent-1);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15), 0 0 20px rgba(99, 102, 241, 0.1);
}

.size-input.has-value {
    border-color: var(--accent-3);
    background: rgba(139, 92, 246, 0.06);
}

.range-hint {
    font-size: var(--font-xs);
    color: var(--text-muted);
    white-space: nowrap;
    min-width: 55px;
    text-align: right;
}

/* Foot length wrapper */
.foot-wrapper {
    display: flex;
    gap: var(--space-sm);
}

.unit-select {
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 12px 14px;
    color: var(--text-primary);
    font-family: var(--font-family);
    font-size: var(--font-sm);
    outline: none;
    cursor: pointer;
    transition: all var(--duration-normal) var(--ease-out);
    min-width: 80px;
    -webkit-appearance: none;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg width='10' height='6' viewBox='0 0 10 6' fill='none' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M1 1L5 5L9 1' stroke='%236a6a8a' stroke-width='1.5' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
    padding-right: 32px;
}

.unit-select:focus {
    border-color: var(--accent-1);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
}

.unit-select option {
    background: var(--bg-secondary);
    color: var(--text-primary);
}

/* ===== Action Buttons ===== */
.actions {
    display: flex;
    gap: var(--space-md);
    margin-top: var(--space-2xl);
    justify-content: center;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    padding: 14px 32px;
    border-radius: var(--radius-full);
    font-family: var(--font-family);
    font-size: var(--font-base);
    font-weight: 600;
    border: none;
    cursor: pointer;
    transition: all var(--duration-normal) var(--ease-spring);
    position: relative;
    overflow: hidden;
    text-decoration: none;
}

.btn-primary {
    background: var(--accent-gradient);
    color: white;
    box-shadow: 0 4px 20px rgba(99, 102, 241, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(99, 102, 241, 0.5);
    color: white;
}

.btn-primary:active {
    transform: translateY(0);
    box-shadow: 0 2px 10px rgba(99, 102, 241, 0.3);
}

.btn-secondary {
    background: var(--bg-input);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.08);
    color: var(--text-primary);
    border-color: var(--border-active);
    transform: translateY(-1px);
}

.btn-secondary:active {
    transform: translateY(0);
}

.btn-outline {
    background: transparent;
    color: var(--text-accent);
    border: 1px solid var(--border-active);
}

.btn-outline:hover {
    background: var(--accent-gradient-subtle);
    color: var(--text-primary);
    transform: translateY(-1px);
}

/* Ripple effect */
.btn::after {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at var(--ripple-x, 50%) var(--ripple-y, 50%), rgba(255, 255, 255, 0.3) 0%, transparent 60%);
    opacity: 0;
    transition: opacity 0.5s;
}

.btn:active::after {
    opacity: 1;
    transition: opacity 0s;
}

/* ===== Error Message ===== */
.error-message {
    margin-top: var(--space-xl);
    padding: var(--space-lg) var(--space-xl);
    background: rgba(245, 158, 11, 0.1);
    border: 1px solid rgba(245, 158, 11, 0.3);
    border-radius: var(--radius-lg);
    color: #fbbf24;
    font-size: var(--font-base);
    font-weight: 600;
    text-align: center;
    animation: fadeInUp 0.4s var(--ease-out) both;
}

.error-message.hidden {
    display: none;
}

.error-icon {
    font-size: var(--font-xl);
    margin-right: var(--space-sm);
}

/* ===== Results Section ===== */
.results-section {
    margin-top: var(--space-2xl);
    animation: fadeInUp 0.6s var(--ease-out) both;
}

.results-section.hidden {
    display: none;
}

.results-title {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-size: var(--font-xl);
    font-weight: 700;
    margin-bottom: var(--space-lg);
    letter-spacing: -0.02em;
}

.results-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-md);
}

.result-card {
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid rgba(99, 102, 241, 0.15);
    border-radius: var(--radius-lg);
    padding: var(--space-lg) var(--space-md);
    text-align: center;
    transition: all var(--duration-normal) var(--ease-out);
    animation: scaleIn 0.4s var(--ease-spring) both;
    position: relative;
    overflow: hidden;
}

.result-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--accent-gradient);
    opacity: 0.5;
    transition: opacity var(--duration-normal);
}

.result-card:hover {
    border-color: rgba(99, 102, 241, 0.35);
    transform: translateY(-6px) scale(1.02);
    box-shadow: 0 12px 40px rgba(99, 102, 241, 0.15), 0 0 40px rgba(99, 102, 241, 0.08);
}

.result-card:hover::before {
    opacity: 1;
}

.result-flag {
    font-size: 2.2rem;
    margin-bottom: var(--space-xs);
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.3));
}

.result-region {
    font-size: var(--font-xs);
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    font-weight: 600;
    margin-bottom: var(--space-sm);
}

.result-value {
    font-size: var(--font-3xl);
    font-weight: 800;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.03em;
    line-height: 1.2;
}

.result-label {
    font-size: var(--font-xs);
    color: var(--text-secondary);
    margin-top: var(--space-sm);
    opacity: 0.8;
}

/* ===== Foot Length Result Card ===== */
.foot-length-result {
    grid-column: 1 / -1;
    background: var(--bg-card);
    border-color: rgba(99, 102, 241, 0.25);
    padding: var(--space-lg) var(--space-xl);
}

.result-foot-values {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2px;
    margin-top: var(--space-xs);
}

.foot-val {
    font-size: var(--font-xl);
    font-weight: 700;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.01em;
    line-height: 1.6;
}

.foot-val small {
    font-size: var(--font-sm);
    font-weight: 500;
    opacity: 0.65;
}

/* ===== How It Works Section ===== */
.how-it-works {
    padding: var(--space-2xl) 0;
    animation: fadeInUp 0.8s var(--ease-out) 0.15s both;
}

.section-heading {
    text-align: center;
    margin-bottom: var(--space-xl);
}

.section-heading h2 {
    font-size: var(--font-3xl);
    font-weight: 800;
    letter-spacing: -0.03em;
    margin-bottom: var(--space-md);
}

.section-heading p {
    font-size: var(--font-lg);
    color: var(--text-secondary);
    max-width: 550px;
    margin: 0 auto;
}

.steps-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-xl);
    position: relative;
}

/* Connector line between steps */
.steps-grid::before {
    content: '';
    position: absolute;
    top: 60px;
    left: 16.67%;
    right: 16.67%;
    height: 2px;
    background: linear-gradient(90deg, transparent, var(--accent-1), var(--accent-2), transparent);
    opacity: 0.3;
    z-index: 0;
}

.step-card {
    text-align: center;
    padding: var(--space-2xl) var(--space-lg);
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    transition: all var(--duration-slow) var(--ease-out);
    position: relative;
    z-index: 1;
}

.step-card:hover {
    border-color: var(--border-active);
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.step-number {
    width: 56px;
    height: 56px;
    border-radius: 50%;
    background: var(--accent-gradient);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-xl);
    font-weight: 800;
    color: white;
    margin: 0 auto var(--space-lg);
    box-shadow: 0 4px 20px rgba(99, 102, 241, 0.3);
}

.step-icon {
    font-size: 2.5rem;
    margin-bottom: var(--space-md);
    display: block;
}

.step-card h3 {
    font-size: var(--font-lg);
    font-weight: 700;
    margin-bottom: var(--space-sm);
    letter-spacing: -0.01em;
}

.step-card p {
    font-size: var(--font-sm);
    color: var(--text-secondary);
    line-height: 1.7;
}

/* ===== Size Chart Section ===== */
.chart-section {
    padding: var(--space-xl) 0;
    animation: fadeInUp 0.8s var(--ease-out) 0.2s both;
}

.chart-title {
    text-align: center;
    font-size: var(--font-xl);
    font-weight: 700;
    margin-bottom: var(--space-lg);
    letter-spacing: -0.02em;
}

.chart-tabs {
    display: flex;
    justify-content: center;
    gap: var(--space-xs);
    margin-bottom: var(--space-xl);
    background: var(--bg-input);
    border-radius: var(--radius-full);
    padding: 4px;
    width: fit-content;
    margin-left: auto;
    margin-right: auto;
}

.chart-tab {
    padding: 10px 24px;
    border-radius: var(--radius-full);
    border: none;
    background: transparent;
    color: var(--text-secondary);
    font-family: var(--font-family);
    font-size: var(--font-sm);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--duration-normal) var(--ease-out);
}

.chart-tab.active {
    background: var(--accent-gradient);
    color: white;
    box-shadow: 0 2px 10px rgba(99, 102, 241, 0.3);
}

.chart-tab:not(.active):hover {
    color: var(--text-primary);
    background: rgba(255, 255, 255, 0.05);
}

.chart-table-wrapper {
    overflow-x: auto;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    scrollbar-width: thin;
    scrollbar-color: var(--accent-3) transparent;
}

.chart-table-wrapper::-webkit-scrollbar {
    height: 6px;
}

.chart-table-wrapper::-webkit-scrollbar-track {
    background: transparent;
}

.chart-table-wrapper::-webkit-scrollbar-thumb {
    background: var(--accent-3);
    border-radius: 3px;
}

.chart-table {
    width: 100%;
    border-collapse: collapse;
    font-size: var(--font-sm);
    white-space: nowrap;
}

.chart-table th {
    background: rgba(99, 102, 241, 0.1);
    padding: 14px 16px;
    font-weight: 600;
    text-align: center;
    color: var(--text-accent);
    font-size: var(--font-xs);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
}

.chart-table td {
    padding: 12px 16px;
    text-align: center;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-secondary);
    transition: all var(--duration-fast);
}

.chart-table tr:hover td {
    background: rgba(99, 102, 241, 0.05);
    color: var(--text-primary);
}

.chart-table tr:last-child td {
    border-bottom: none;
}

/* ===== FAQ Section ===== */
.faq-section {
    padding: var(--space-2xl) 0;
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.faq-item {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    overflow: hidden;
    transition: all var(--duration-normal) var(--ease-out);
}

.faq-item:hover {
    border-color: var(--border-active);
}

.faq-item[open] {
    border-color: rgba(99, 102, 241, 0.3);
    box-shadow: 0 4px 20px rgba(99, 102, 241, 0.08);
}

.faq-question {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-lg) var(--space-xl);
    cursor: pointer;
    font-size: var(--font-base);
    font-weight: 600;
    color: var(--text-primary);
    user-select: none;
    list-style: none;
    transition: color var(--duration-normal);
}

.faq-question::-webkit-details-marker {
    display: none;
}

.faq-question::after {
    content: '';
    width: 10px;
    height: 10px;
    border-right: 2px solid var(--text-muted);
    border-bottom: 2px solid var(--text-muted);
    transform: rotate(45deg);
    transition: transform var(--duration-normal) var(--ease-out);
    flex-shrink: 0;
    margin-left: var(--space-md);
}

.faq-item[open] .faq-question::after {
    transform: rotate(-135deg);
}

.faq-answer {
    padding: 0 var(--space-xl) var(--space-lg);
    color: var(--text-secondary);
    font-size: var(--font-sm);
    line-height: 1.8;
    animation: fadeInDown 0.3s var(--ease-out);
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-8px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ===== Content Sections (General) ===== */
.content-section {
    padding: var(--space-2xl) 0;
}

.content-section+.content-section {
    padding-top: 0;
}

/* ===== Chart Description ===== */
.chart-description {
    text-align: center;
    margin-bottom: var(--space-xl);
    max-width: 750px;
    margin-left: auto;
    margin-right: auto;
}

.chart-description p {
    font-size: var(--font-sm);
    color: var(--text-secondary);
    line-height: 1.7;
}

/* ===== Formula Cards ===== */
.formula-grid {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.formula-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    overflow: hidden;
    transition: all var(--duration-normal) var(--ease-out);
}

.formula-card:hover {
    border-color: var(--border-active);
}

.formula-card.open {
    border-color: rgba(99, 102, 241, 0.3);
    box-shadow: 0 4px 20px rgba(99, 102, 241, 0.08);
}

.formula-card-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-lg) var(--space-xl);
    cursor: pointer;
    user-select: none;
    transition: background var(--duration-normal);
}

.formula-card-header:hover {
    background: rgba(99, 102, 241, 0.03);
}

.formula-card-title {
    display: flex;
    align-items: center;
    gap: var(--space-md);
}

.formula-card-title h3 {
    font-size: var(--font-base);
    font-weight: 700;
    color: var(--text-primary);
    margin: 0;
}

.formula-flag {
    font-size: 1.8rem;
    line-height: 1;
}

.formula-toggle-icon {
    font-size: var(--font-xl);
    font-weight: 300;
    color: var(--text-muted);
    transition: transform var(--duration-normal) var(--ease-out);
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: var(--bg-input);
    flex-shrink: 0;
}

.formula-card.open .formula-toggle-icon {
    transform: rotate(45deg);
    background: var(--accent-gradient-subtle);
    color: var(--text-accent);
}

.formula-card-body {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s var(--ease-out), padding 0.3s var(--ease-out);
    padding: 0 var(--space-xl);
}

.formula-card.open .formula-card-body {
    max-height: 800px;
    padding: 0 var(--space-xl) var(--space-xl);
}

.formula-card-body p {
    font-size: var(--font-sm);
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: var(--space-md);
}

.formula-block {
    background: rgba(99, 102, 241, 0.05);
    border: 1px solid rgba(99, 102, 241, 0.15);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    margin-bottom: var(--space-md);
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

.formula-equation {
    font-family: 'Inter', monospace;
    font-size: var(--font-sm);
    color: var(--text-primary);
    padding: var(--space-sm) 0;
    border-bottom: 1px dashed rgba(99, 102, 241, 0.1);
}

.formula-equation:last-child {
    border-bottom: none;
}

.formula-example {
    background: rgba(34, 197, 94, 0.06);
    border: 1px solid rgba(34, 197, 94, 0.2);
    border-radius: var(--radius-md);
    padding: var(--space-md) var(--space-lg);
    font-size: var(--font-sm);
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: var(--space-md);
}

/* ===== Mini Calculator ===== */
.mini-calculator {
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    margin-top: var(--space-sm);
}

.mini-calc-label {
    font-size: var(--font-sm) !important;
    font-weight: 600 !important;
    color: var(--text-primary) !important;
    margin-bottom: var(--space-sm) !important;
}

.mini-calc-row {
    display: flex;
    gap: var(--space-sm);
    align-items: center;
}

.mini-calc-input {
    flex: 1;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 10px 14px;
    color: var(--text-primary);
    font-family: var(--font-family);
    font-size: var(--font-sm);
    outline: none;
    transition: all var(--duration-normal) var(--ease-out);
    -moz-appearance: textfield;
}

.mini-calc-input::-webkit-outer-spin-button,
.mini-calc-input::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

.mini-calc-input:focus {
    border-color: var(--accent-1);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
}

.mini-calc-btn {
    padding: 10px 20px !important;
    font-size: var(--font-sm) !important;
    white-space: nowrap;
}

.mini-calc-result {
    margin-top: var(--space-md);
    padding: var(--space-md);
    background: rgba(99, 102, 241, 0.06);
    border-radius: var(--radius-md);
    font-size: var(--font-sm);
    color: var(--text-primary);
    line-height: 1.7;
}

.mini-calc-result.hidden {
    display: none;
}

/* ===== How-To Steps ===== */
.how-to-steps {
    display: flex;
    flex-direction: column;
    gap: var(--space-lg);
    max-width: 800px;
    margin: 0 auto;
}

.how-to-step {
    display: flex;
    gap: var(--space-xl);
    padding: var(--space-xl);
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    transition: all var(--duration-normal) var(--ease-out);
    align-items: flex-start;
}

.how-to-step:hover {
    border-color: var(--border-active);
    transform: translateX(4px);
    box-shadow: var(--shadow-md), var(--shadow-glow);
}

.how-to-step-number {
    width: 48px;
    height: 48px;
    min-width: 48px;
    border-radius: 50%;
    background: var(--accent-gradient);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-lg);
    font-weight: 800;
    color: white;
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.3);
}

.how-to-step-content h3 {
    font-size: var(--font-base);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--space-sm);
}

.how-to-step-content p {
    font-size: var(--font-sm);
    color: var(--text-secondary);
    line-height: 1.8;
    margin: 0;
}

/* ===== Measurement Section ===== */
.measurement-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-xl);
}

.measurement-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--space-xl);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    transition: all var(--duration-normal) var(--ease-out);
}

.measurement-card:hover {
    border-color: var(--border-active);
    box-shadow: var(--shadow-md), var(--shadow-glow);
}

.measurement-card--wide {
    grid-column: 1 / -1;
}

.measurement-card-icon {
    font-size: 2rem;
    margin-bottom: var(--space-md);
}

.measurement-card h3 {
    font-size: var(--font-lg);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--space-md);
}

.measurement-card p {
    font-size: var(--font-sm);
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: var(--space-md);
}

.measurement-card p:last-child {
    margin-bottom: 0;
}

.measurement-steps-list {
    list-style: none;
    counter-reset: step-counter;
    padding-left: 0;
    margin-bottom: var(--space-md);
}

.measurement-steps-list li {
    counter-increment: step-counter;
    position: relative;
    padding-left: calc(var(--space-xl) + var(--space-sm));
    margin-bottom: var(--space-sm);
    font-size: var(--font-sm);
    color: var(--text-secondary);
    line-height: 1.8;
}

.measurement-steps-list li::before {
    content: counter(step-counter);
    position: absolute;
    left: 0;
    top: 2px;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: var(--accent-gradient);
    color: white;
    font-size: var(--font-xs);
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* ===== Foot Diagram ===== */
.foot-diagram {
    margin-top: var(--space-lg);
    display: flex;
    justify-content: center;
}

.foot-diagram-visual {
    max-width: 300px;
    width: 100%;
}

.foot-outline {
    position: relative;
    width: 100%;
    padding-bottom: 120%;
}

.foot-shape {
    position: absolute;
    inset: 10% 20%;
}

.foot-shape svg {
    width: 100%;
    height: 100%;
}

.measure-line {
    position: absolute;
}

.measure-line--length {
    right: 8%;
    top: 5%;
    bottom: 5%;
    width: 2px;
    background: var(--accent-gradient);
    display: flex;
    align-items: center;
}

.measure-line--length::before,
.measure-line--length::after {
    content: '';
    position: absolute;
    width: 12px;
    height: 2px;
    background: var(--accent-1);
}

.measure-line--length::before {
    top: 0;
    right: -5px;
}

.measure-line--length::after {
    bottom: 0;
    right: -5px;
}

.measure-line--length .measure-label {
    position: absolute;
    right: -80px;
    top: 50%;
    transform: translateY(-50%);
    font-size: var(--font-xs);
    color: var(--text-accent);
    font-weight: 600;
    white-space: nowrap;
}

.measure-line--width {
    bottom: 40%;
    left: 18%;
    right: 18%;
    height: 2px;
    background: linear-gradient(90deg, var(--accent-1), var(--accent-2));
}

.measure-line--width::before,
.measure-line--width::after {
    content: '';
    position: absolute;
    width: 2px;
    height: 12px;
    background: var(--accent-2);
}

.measure-line--width::before {
    left: 0;
    top: -5px;
}

.measure-line--width::after {
    right: 0;
    top: -5px;
}

.measure-line--width .measure-label {
    position: absolute;
    bottom: -22px;
    left: 50%;
    transform: translateX(-50%);
    font-size: var(--font-xs);
    color: var(--accent-2);
    font-weight: 600;
    white-space: nowrap;
}

.measure-point {
    position: absolute;
    font-size: 10px;
    font-weight: 600;
    color: var(--text-muted);
    background: var(--bg-secondary);
    padding: 2px 6px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-color);
}

.measure-point--heel {
    bottom: 5%;
    left: 50%;
    transform: translateX(-50%);
}

.measure-point--toe {
    top: 3%;
    left: 50%;
    transform: translateX(-50%);
}

.measure-point--ball {
    bottom: 40%;
    left: 4%;
    transform: translateY(50%);
}

/* ===== Unit Converter Mini ===== */
.unit-converter-mini {
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    margin-top: var(--space-md);
}

.unit-conv-row {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    flex-wrap: wrap;
}

.unit-conv-field {
    flex: 1;
    min-width: 80px;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.unit-conv-field label {
    font-size: var(--font-xs);
    color: var(--text-muted);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.unit-conv-equals {
    font-size: var(--font-lg);
    color: var(--text-muted);
    font-weight: 300;
    padding-bottom: 18px;
}

/* ===== Systems Grid ===== */
.systems-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-xl);
    margin-bottom: var(--space-3xl);
}

.system-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--space-xl);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    transition: all var(--duration-normal) var(--ease-out);
    position: relative;
    overflow: hidden;
}

.system-card:hover {
    border-color: var(--border-active);
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.system-card-badge {
    position: absolute;
    top: var(--space-md);
    right: var(--space-md);
    background: var(--accent-gradient);
    color: white;
    font-size: 10px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    padding: 4px 10px;
    border-radius: var(--radius-full);
}

.system-card-icon {
    font-size: 2.5rem;
    margin-bottom: var(--space-md);
}

.system-card h3 {
    font-size: var(--font-lg);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--space-md);
}

.system-card p {
    font-size: var(--font-sm);
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: var(--space-md);
}

.system-measurements {
    display: flex;
    gap: var(--space-sm);
    flex-wrap: wrap;
    margin-top: var(--space-sm);
}

.system-measure-tag {
    background: var(--accent-gradient-subtle);
    border: 1px solid rgba(99, 102, 241, 0.15);
    border-radius: var(--radius-full);
    padding: 4px 12px;
    font-size: var(--font-xs);
    font-weight: 600;
    color: var(--text-accent);
}

/* ===== System Comparison Table ===== */
.system-comparison {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--space-xl);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
}

.system-comparison h3 {
    font-size: var(--font-lg);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--space-lg);
    text-align: center;
}

.comparison-table {
    width: 100%;
    border-collapse: collapse;
    font-size: var(--font-sm);
}

.comparison-table th {
    background: rgba(99, 102, 241, 0.08);
    padding: 12px 16px;
    font-weight: 600;
    text-align: center;
    color: var(--text-accent);
    font-size: var(--font-xs);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border-bottom: 1px solid var(--border-color);
}

.comparison-table td {
    padding: 12px 16px;
    text-align: center;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-secondary);
}

.comparison-table tr:hover td {
    background: rgba(99, 102, 241, 0.03);
    color: var(--text-primary);
}

.comparison-table tr:last-child td {
    border-bottom: none;
}

/* ===== Factors Grid ===== */
.factors-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-xl);
}

.factor-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--space-xl);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    transition: all var(--duration-slow) var(--ease-out);
}

.factor-card:hover {
    border-color: var(--border-active);
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.factor-card-icon {
    font-size: 2rem;
    margin-bottom: var(--space-md);
}

.factor-card h3 {
    font-size: var(--font-base);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--space-sm);
}

.factor-card p {
    font-size: var(--font-sm);
    color: var(--text-secondary);
    line-height: 1.8;
    margin: 0;
}

/* ===== Tips Grid ===== */
.tips-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-xl);
}

.tip-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--space-xl);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    transition: all var(--duration-normal) var(--ease-out);
    position: relative;
    overflow: hidden;
}

.tip-card:hover {
    border-color: var(--border-active);
    transform: translateY(-4px);
    box-shadow: var(--shadow-md), var(--shadow-glow);
}

.tip-number {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: var(--accent-gradient);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-base);
    font-weight: 800;
    color: white;
    margin-bottom: var(--space-md);
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.25);
}

.tip-card h3 {
    font-size: var(--font-base);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--space-sm);
}

.tip-card p {
    font-size: var(--font-sm);
    color: var(--text-secondary);
    line-height: 1.8;
    margin: 0;
}

/* ===== Responsive for New Sections ===== */
@media (max-width: 1024px) {
    .systems-grid {
        grid-template-columns: 1fr;
    }

    .factors-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .content-section {
        padding: var(--space-xl) 0;
    }

    .measurement-grid {
        grid-template-columns: 1fr;
    }

    .factors-grid {
        grid-template-columns: 1fr;
    }

    .tips-grid {
        grid-template-columns: 1fr;
    }

    .how-to-step {
        flex-direction: column;
        gap: var(--space-md);
        align-items: flex-start;
    }

    .comparison-table {
        font-size: var(--font-xs);
    }

    .comparison-table th,
    .comparison-table td {
        padding: 8px 10px;
    }

    .unit-conv-row {
        flex-direction: column;
    }

    .unit-conv-equals {
        padding-bottom: 0;
    }

    .formula-card-header {
        padding: var(--space-md) var(--space-lg);
    }

    .formula-card-body {
        padding-left: var(--space-lg);
        padding-right: var(--space-lg);
    }

    .formula-card.open .formula-card-body {
        padding-left: var(--space-lg);
        padding-right: var(--space-lg);
    }

    .mini-calc-row {
        flex-direction: column;
    }
}

@media (max-width: 640px) {
    .chart-tabs {
        flex-wrap: wrap;
        border-radius: var(--radius-lg);
    }

    .chart-tab {
        padding: 8px 14px;
        font-size: var(--font-xs);
    }
}

/* ===== Footer ===== */
.site-footer {
    margin-top: var(--space-xl);
    border-top: 1px solid var(--border-color);
    background: rgba(255, 255, 255, 0.6);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
}

.footer-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--space-3xl) var(--space-lg) var(--space-xl);
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: var(--space-3xl);
    margin-bottom: var(--space-3xl);
}

.footer-brand {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.footer-brand .logo {
    margin-bottom: var(--space-xs);
}

.footer-description {
    font-size: var(--font-sm);
    color: var(--text-secondary);
    line-height: 1.7;
    max-width: 320px;
}

.footer-social {
    display: flex;
    gap: var(--space-sm);
    margin-top: var(--space-sm);
}

.social-icon {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-md);
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-secondary);
    text-decoration: none;
    transition: all var(--duration-normal) var(--ease-out);
}

.social-icon:hover {
    background: var(--accent-gradient-subtle);
    border-color: var(--border-active);
    color: var(--text-primary);
    transform: translateY(-2px);
}

.social-icon svg {
    width: 18px;
    height: 18px;
}

.footer-column h4 {
    font-size: var(--font-sm);
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-primary);
    margin-bottom: var(--space-lg);
}

.footer-links {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

.footer-link {
    font-size: var(--font-sm);
    color: var(--text-secondary);
    text-decoration: none;
    transition: all var(--duration-normal) var(--ease-out);
    display: flex;
    align-items: center;
    gap: var(--space-xs);
}

.footer-link:hover {
    color: var(--text-accent);
    transform: translateX(4px);
}

.footer-bottom {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-top: var(--space-xl);
    border-top: 1px solid var(--border-color);
    gap: var(--space-md);
}

.footer-copyright {
    font-size: var(--font-sm);
    color: var(--text-muted);
}

.footer-disclaimer {
    font-size: var(--font-xs);
    color: var(--text-muted);
    opacity: 0.6;
}

/* ===== Footer Language Switcher ===== */
.footer-language {
    padding: var(--space-xl) 0;
    border-top: 1px solid var(--border-color);
    margin-bottom: var(--space-lg);
}

.footer-language h4 {
    font-size: var(--font-sm);
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-primary);
    margin-bottom: var(--space-lg);
}

.language-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.lang-btn {
    padding: 6px 16px;
    border-radius: 999px;
    border: 1px solid var(--border-color);
    background: transparent;
    color: var(--text-secondary);
    font-size: var(--font-sm);
    font-family: inherit;
    cursor: pointer;
    transition: all var(--duration-normal) var(--ease-out);
    white-space: nowrap;
}

.lang-btn:hover {
    border-color: var(--border-active);
    color: var(--text-primary);
    background: var(--bg-input);
}

.lang-btn.active {
    border-color: var(--text-accent);
    color: var(--text-accent);
    background: rgba(99, 102, 241, 0.08);
    font-weight: 600;
}

/* ===== Page Hero (Inner Pages) ===== */
.page-hero {
    text-align: center;
    padding: var(--space-4xl) 0 var(--space-2xl);
    animation: fadeInUp 0.6s var(--ease-out) both;
}

.page-hero h1 {
    font-size: var(--font-3xl);
    font-weight: 800;
    letter-spacing: -0.03em;
    margin-bottom: var(--space-md);
}

.page-hero p {
    font-size: var(--font-lg);
    color: var(--text-secondary);
    max-width: 550px;
    margin: 0 auto;
    line-height: 1.7;
}

/* ===== Content Card (shared for inner pages) ===== */
.content-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--space-3xl);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    margin-bottom: var(--space-2xl);
    animation: fadeInUp 0.6s var(--ease-out) 0.1s both;
}

.content-card h2 {
    font-size: var(--font-xl);
    font-weight: 700;
    margin-bottom: var(--space-md);
    letter-spacing: -0.01em;
    color: var(--text-primary);
}

.content-card h3 {
    font-size: var(--font-lg);
    font-weight: 600;
    margin-top: var(--space-xl);
    margin-bottom: var(--space-sm);
    color: var(--text-accent);
}

.content-card p {
    font-size: var(--font-base);
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: var(--space-md);
}

.content-card ul {
    margin-bottom: var(--space-md);
    padding-left: var(--space-lg);
}

.content-card li {
    font-size: var(--font-base);
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: var(--space-sm);
    position: relative;
    padding-left: var(--space-md);
}

.content-card li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 12px;
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--accent-gradient);
}

.content-card a {
    color: var(--text-accent);
    text-decoration: underline;
    text-underline-offset: 3px;
}

.content-card a:hover {
    color: var(--accent-2);
}

/* ===== About Page ===== */
.about-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-xl);
    margin-top: var(--space-2xl);
}

.about-stat {
    text-align: center;
    padding: var(--space-xl);
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    transition: all var(--duration-normal) var(--ease-out);
}

.about-stat:hover {
    border-color: var(--border-active);
    transform: translateY(-4px);
    box-shadow: var(--shadow-md), var(--shadow-glow);
}

.about-stat-icon {
    font-size: 2.5rem;
    margin-bottom: var(--space-sm);
}

.about-stat-value {
    font-size: var(--font-2xl);
    font-weight: 800;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.about-stat-label {
    font-size: var(--font-sm);
    color: var(--text-secondary);
    margin-top: var(--space-xs);
}

.mission-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-xl);
    margin-top: var(--space-xl);
}

.mission-card {
    padding: var(--space-xl);
    background: var(--accent-gradient-subtle);
    border: 1px solid rgba(99, 102, 241, 0.15);
    border-radius: var(--radius-lg);
    transition: all var(--duration-normal) var(--ease-out);
}

.mission-card:hover {
    border-color: var(--border-active);
    transform: translateY(-4px);
}

.mission-card h3 {
    font-size: var(--font-base);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--space-sm);
    margin-top: 0;
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.mission-card p {
    font-size: var(--font-sm);
    margin-bottom: 0;
}

/* ===== Contact Page ===== */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-2xl);
    margin-top: var(--space-xl);
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: var(--space-xl);
}

.contact-method {
    display: flex;
    gap: var(--space-md);
    padding: var(--space-lg);
    background: var(--accent-gradient-subtle);
    border: 1px solid rgba(99, 102, 241, 0.15);
    border-radius: var(--radius-lg);
    transition: all var(--duration-normal) var(--ease-out);
}

.contact-method:hover {
    border-color: var(--border-active);
    transform: translateY(-2px);
}

.contact-method-icon {
    font-size: 1.5rem;
    flex-shrink: 0;
}

.contact-method h3 {
    font-size: var(--font-base);
    font-weight: 600;
    margin-bottom: var(--space-xs);
    color: var(--text-primary);
}

.contact-method p {
    font-size: var(--font-sm);
    color: var(--text-secondary);
    margin-bottom: 0;
}

.contact-form {
    display: flex;
    flex-direction: column;
    gap: var(--space-lg);
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

.form-label {
    font-size: var(--font-sm);
    font-weight: 600;
    color: var(--text-primary);
}

.form-input,
.form-textarea {
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 14px 18px;
    color: var(--text-primary);
    font-family: var(--font-family);
    font-size: var(--font-base);
    outline: none;
    transition: all var(--duration-normal) var(--ease-out);
    width: 100%;
}

.form-textarea {
    min-height: 140px;
    resize: vertical;
}

.form-input::placeholder,
.form-textarea::placeholder {
    color: var(--text-muted);
}

.form-input:focus,
.form-textarea:focus {
    background: var(--bg-input-focus);
    border-color: var(--accent-1);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15), 0 0 20px rgba(99, 102, 241, 0.1);
}

.form-status {
    padding: var(--space-md) var(--space-lg);
    border-radius: var(--radius-md);
    font-size: var(--font-sm);
    font-weight: 500;
    text-align: center;
    display: none;
}

.form-status.success {
    display: block;
    background: rgba(34, 197, 94, 0.1);
    border: 1px solid rgba(34, 197, 94, 0.3);
    color: #4ade80;
}

.form-status.error {
    display: block;
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.3);
    color: #f87171;
}

.form-status.sending {
    display: block;
    background: rgba(99, 102, 241, 0.1);
    border: 1px solid rgba(99, 102, 241, 0.3);
    color: var(--text-accent);
}

/* ===== Blog Page ===== */
.blog-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-xl);
    margin-top: var(--space-xl);
}

.blog-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    overflow: hidden;
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    transition: all var(--duration-slow) var(--ease-out);
    display: flex;
    flex-direction: column;
}

.blog-card:hover {
    border-color: var(--border-active);
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.blog-card-image {
    height: 200px;
    background: var(--accent-gradient-subtle);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 3rem;
    border-bottom: 1px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

.blog-card-image::before {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--accent-gradient);
    opacity: 0.05;
}

.blog-card-body {
    padding: var(--space-xl);
    display: flex;
    flex-direction: column;
    flex: 1;
}

.blog-card-category {
    font-size: var(--font-xs);
    color: var(--text-accent);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    font-weight: 600;
    margin-bottom: var(--space-sm);
}

.blog-card-title {
    font-size: var(--font-lg);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--space-sm);
    letter-spacing: -0.01em;
    line-height: 1.4;
}

.blog-card-excerpt {
    font-size: var(--font-sm);
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: var(--space-lg);
    flex: 1;
}

.blog-card-meta {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-top: var(--space-md);
    border-top: 1px solid var(--border-color);
}

.blog-card-date {
    font-size: var(--font-xs);
    color: var(--text-muted);
}

.blog-card-cta {
    font-size: var(--font-sm);
    font-weight: 600;
    color: var(--text-accent);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    transition: all var(--duration-normal) var(--ease-out);
}

.blog-card-cta:hover {
    color: var(--accent-2);
    gap: var(--space-sm);
}

/* ===== 404 Page ===== */
.error-page {
    text-align: center;
    padding: var(--space-4xl) 0;
    min-height: 60vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.error-404-icon {
    font-size: 6rem;
    margin-bottom: var(--space-xl);
    animation: float404 3s ease-in-out infinite;
}

@keyframes float404 {

    0%,
    100% {
        transform: translateY(0) rotate(0deg);
    }

    25% {
        transform: translateY(-15px) rotate(-5deg);
    }

    75% {
        transform: translateY(-5px) rotate(5deg);
    }
}

.error-404-code {
    font-size: 8rem;
    font-weight: 900;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1;
    margin-bottom: var(--space-md);
    letter-spacing: -0.05em;
}

.error-page h1 {
    font-size: var(--font-2xl);
    font-weight: 700;
    margin-bottom: var(--space-md);
}

.error-page p {
    font-size: var(--font-lg);
    color: var(--text-secondary);
    max-width: 450px;
    margin: 0 auto var(--space-xl);
}

/* ===== Animations ===== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes scaleIn {
    from {
        opacity: 0;
        transform: scale(0.9);
    }

    to {
        opacity: 1;
        transform: scale(1);
    }
}

/* ===== Responsive ===== */
@media (max-width: 1024px) {
    .footer-grid {
        grid-template-columns: 1fr 1fr;
        gap: var(--space-2xl);
    }

    .footer-brand {
        grid-column: 1 / -1;
    }

    .blog-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .steps-grid::before {
        display: none;
    }
}

@media (max-width: 768px) {
    .desktop-nav {
        display: none;
    }

    .hamburger {
        display: flex;
    }

    .hero h1 {
        font-size: var(--font-2xl);
    }

    .hero-subtitle {
        font-size: var(--font-base);
    }

    .section-heading h2 {
        font-size: var(--font-2xl);
    }

    .steps-grid {
        grid-template-columns: 1fr;
        gap: var(--space-lg);
    }

    .about-grid {
        grid-template-columns: 1fr;
    }

    .mission-grid {
        grid-template-columns: 1fr;
    }

    .contact-grid {
        grid-template-columns: 1fr;
    }

    .blog-grid {
        grid-template-columns: 1fr;
    }

    .footer-grid {
        grid-template-columns: 1fr;
        gap: var(--space-xl);
    }

    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }

    .page-hero h1 {
        font-size: var(--font-2xl);
    }

    .content-card {
        padding: var(--space-xl);
    }
}

@media (max-width: 640px) {
    .converter-card {
        padding: var(--space-lg);
        border-radius: var(--radius-lg);
    }

    .category-options {
        flex-direction: column;
    }

    .category-pill {
        justify-content: center;
    }

    .input-row {
        grid-template-columns: 1fr;
        gap: var(--space-sm);
    }

    .field-label {
        font-size: var(--font-sm);
    }

    .results-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .result-value {
        font-size: var(--font-2xl);
    }

    .foot-val {
        font-size: var(--font-lg);
    }

    .actions {
        flex-direction: column;
        align-items: stretch;
    }

    .btn {
        justify-content: center;
    }

    .error-404-code {
        font-size: 5rem;
    }
}

@media (max-width: 400px) {
    .results-grid {
        grid-template-columns: 1fr;
    }
}

/* ===== Input animation on value ===== */
.size-input.pulse {
    animation: inputPulse 0.3s var(--ease-spring);
}

@keyframes inputPulse {
    0% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.02);
    }

    100% {
        transform: scale(1);
    }
}

/* ===== Result card stagger ===== */
.result-card:nth-child(1) {
    animation-delay: 0ms;
}

.result-card:nth-child(2) {
    animation-delay: 50ms;
}

.result-card:nth-child(3) {
    animation-delay: 100ms;
}

.result-card:nth-child(4) {
    animation-delay: 150ms;
}

.result-card:nth-child(5) {
    animation-delay: 200ms;
}

.result-card:nth-child(6) {
    animation-delay: 250ms;
}

.result-card:nth-child(7) {
    animation-delay: 300ms;
}

.result-card:nth-child(8) {
    animation-delay: 350ms;
}

/* ===== Utility ===== */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

.hidden {
    display: none !important;
}