/* =====================================================
   手作課作品上傳平台 — 樣式表
   Design System: Playful Creative (Fredoka + Nunito)
   Color Palette: Educational App (Indigo + Orange)
   Accessibility: WCAG AA compliant
   ===================================================== */

/* ========== CSS Variables ========== */
:root {
    /* Primary Palette — Educational Playful */
    --primary: #4F46E5;
    --primary-dark: #4338CA;
    --primary-light: #818CF8;
    --primary-bg: #EEF2FF;

    /* Accent — Energetic Orange */
    --accent: #F97316;
    --accent-light: #FB923C;
    --accent-dark: #EA580C;

    /* Semantic colors */
    --success: #22C55E;
    --info: #3B82F6;
    --warning: #EAB308;

    /* Neutrals */
    --bg: #FAFBFF;
    --bg-white: #FFFFFF;
    --bg-section: #F1F5FE;
    --text: #1E1B4B;
    --text-secondary: #475569;
    --text-muted: #94A3B8;
    --border: #E2E8F0;
    --border-light: #F1F5F9;

    /* Shadows */
    --shadow-xs: 0 1px 2px rgba(79, 70, 229, 0.05);
    --shadow-sm: 0 2px 8px rgba(79, 70, 229, 0.08);
    --shadow-md: 0 8px 30px rgba(79, 70, 229, 0.12);
    --shadow-lg: 0 20px 60px rgba(79, 70, 229, 0.15);
    --shadow-glow: 0 0 40px rgba(79, 70, 229, 0.2);

    /* Radius */
    --radius-sm: 8px;
    --radius-md: 16px;
    --radius-lg: 24px;
    --radius-xl: 32px;
    --radius-full: 9999px;

    /* Card accent colors — Vibrant & Distinct */
    --class-1: #6366F1;  /* Indigo */
    --class-1-light: #A5B4FC;
    --class-2: #EF4444;  /* Red */
    --class-2-light: #FCA5A5;
    --class-3: #10B981;  /* Emerald */
    --class-3-light: #6EE7B7;
    --class-4: #F59E0B;  /* Amber */
    --class-4-light: #FCD34D;
    --class-5: #3B82F6;  /* Blue */
    --class-5-light: #93C5FD;
    --class-6: #8B5CF6;  /* Violet */
    --class-6-light: #C4B5FD;

    /* Typography */
    --font-heading: 'Fredoka', -apple-system, sans-serif;
    --font-body: 'Nunito', -apple-system, "Microsoft JhengHei", "PingFang TC", sans-serif;

    /* Transitions */
    --ease-bounce: cubic-bezier(0.175, 0.885, 0.32, 1.275);
    --ease-smooth: cubic-bezier(0.4, 0, 0.2, 1);
    --duration-fast: 200ms;
    --duration-normal: 300ms;
    --duration-slow: 500ms;
}

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

/* Lighthouse: 所有互動元素加入 pointer cursor */
button, [role="button"], a, summary, [tabindex]:not([tabindex="-1"]) {
    cursor: pointer;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-body);
    background: var(--bg);
    color: var(--text);
    line-height: 1.7;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    line-height: 1.3;
}

a {
    text-decoration: none;
    color: inherit;
    cursor: pointer;
}

ul { list-style: none; }

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

button {
    cursor: pointer;
    font-family: inherit;
}

/* Focus visible for accessibility */
:focus-visible {
    outline: 3px solid var(--primary);
    outline-offset: 2px;
    border-radius: 4px;
}

/* Reduced motion support */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    html { scroll-behavior: auto; }
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

.section {
    padding: 100px 0;
    position: relative;
}

/* ========== Loader ========== */
.loader {
    position: fixed;
    inset: 0;
    z-index: 9999;
    background: var(--bg);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: opacity 0.5s, visibility 0.5s;
}

.loader.hidden {
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
}

.loader-content {
    text-align: center;
}

.loader-icon {
    font-size: 3rem;
    margin-bottom: 20px;
    display: flex;
    gap: 16px;
    justify-content: center;
}

.loader-scissors {
    animation: loaderBounce 0.8s ease-in-out infinite;
}

.loader-palette {
    animation: loaderBounce 0.8s ease-in-out infinite 0.2s;
}

@keyframes loaderBounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-12px); }
}

.loader-bar {
    width: 200px;
    height: 4px;
    background: var(--border);
    border-radius: var(--radius-full);
    overflow: hidden;
}

.loader-progress {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    border-radius: var(--radius-full);
    animation: loaderFill 1.2s ease-out forwards;
}

@keyframes loaderFill {
    from { width: 0; }
    to { width: 100%; }
}

/* ========== Navbar ========== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid transparent;
    transition: all var(--duration-normal) var(--ease-smooth);
}

.navbar.scrolled {
    background: rgba(255, 255, 255, 0.95);
    border-bottom-color: var(--border);
    box-shadow: var(--shadow-sm);
}

.nav-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    height: 68px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 1.05rem;
    font-family: var(--font-heading);
    color: var(--text);
    transition: opacity var(--duration-fast);
}

.nav-brand:hover { opacity: 0.8; }

.nav-logo {
    flex-shrink: 0;
    line-height: 0;
}

.nav-links {
    display: flex;
    gap: 8px;
}

.nav-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
    padding: 8px 16px;
    border-radius: var(--radius-full);
    transition: all var(--duration-fast) var(--ease-smooth);
}

.nav-link:hover {
    color: var(--primary);
    background: var(--primary-bg);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    padding: 8px;
    border-radius: var(--radius-sm);
    transition: background var(--duration-fast);
}

.nav-toggle:hover { background: var(--bg-section); }

.nav-toggle span {
    width: 22px;
    height: 2px;
    background: var(--text);
    border-radius: 2px;
    transition: var(--duration-normal);
}

.nav-toggle.active span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.nav-toggle.active span:nth-child(2) {
    opacity: 0;
}

.nav-toggle.active span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* ========== Hero ========== */
.hero {
    position: relative;
    min-height: 100vh;
    min-height: 100dvh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
    z-index: 0;
}

.hero-pattern {
    position: absolute;
    inset: 0;
    background-image:
        radial-gradient(circle at 20% 50%, rgba(255,255,255,0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(255,255,255,0.08) 0%, transparent 40%),
        radial-gradient(circle at 60% 80%, rgba(255,255,255,0.06) 0%, transparent 40%);
}

/* Floating craft items */
.floating-crafts {
    position: absolute;
    inset: 0;
    z-index: 1;
    pointer-events: none;
}

.craft-item {
    position: absolute;
    font-size: 2rem;
    opacity: 0.15;
    animation: craftFloat var(--duration) ease-in-out infinite;
    filter: blur(0.5px);
}

.craft-1  { left: 5%;  top: 15%; --duration: 7s;  animation-delay: 0s; }
.craft-2  { left: 15%; top: 70%; --duration: 9s;  animation-delay: 1s; }
.craft-3  { left: 85%; top: 20%; --duration: 8s;  animation-delay: 0.5s; }
.craft-4  { left: 75%; top: 75%; --duration: 10s; animation-delay: 2s; }
.craft-5  { left: 45%; top: 10%; --duration: 6s;  animation-delay: 1.5s; }
.craft-6  { left: 90%; top: 50%; --duration: 11s; animation-delay: 0.8s; }
.craft-7  { left: 10%; top: 45%; --duration: 8.5s; animation-delay: 3s; }
.craft-8  { left: 60%; top: 85%; --duration: 7.5s; animation-delay: 2.5s; }
.craft-9  { left: 30%; top: 30%; --duration: 9.5s; animation-delay: 1.2s; }
.craft-10 { left: 50%; top: 55%; --duration: 6.5s; animation-delay: 0.3s; }

@keyframes craftFloat {
    0%, 100% { transform: translateY(0) rotate(0deg) scale(1); }
    25% { transform: translateY(-20px) rotate(5deg) scale(1.1); }
    50% { transform: translateY(-10px) rotate(-3deg) scale(1.05); }
    75% { transform: translateY(-25px) rotate(3deg) scale(0.95); }
}

.hero-content {
    position: relative;
    z-index: 2;
    padding: 0 24px;
    max-width: 800px;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 20px;
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: var(--radius-full);
    color: white;
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 24px;
    animation: fadeInDown 0.8s ease-out;
}

.badge-dot {
    width: 8px;
    height: 8px;
    background: #22C55E;
    border-radius: 50%;
    animation: dotPulse 2s ease-in-out infinite;
}

@keyframes dotPulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.5; transform: scale(1.3); }
}

.hero-title {
    font-size: clamp(2.5rem, 7vw, 5rem);
    font-weight: 700;
    color: white;
    line-height: 1.15;
    margin-bottom: 20px;
    animation: fadeInUp 0.8s ease-out 0.2s both;
}

.title-line {
    display: block;
}

.title-gradient {
    background: linear-gradient(90deg, #FFD93D, #FF6B6B, #FF6B6B);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    background-size: 200% 100%;
    animation: fadeInUp 0.8s ease-out 0.2s both, gradientShift 4s ease-in-out infinite;
}

@keyframes gradientShift {
    0%, 100% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
}

.hero-subtitle {
    font-size: clamp(1rem, 2.5vw, 1.25rem);
    color: rgba(255, 255, 255, 0.85);
    margin-bottom: 36px;
    font-weight: 400;
    line-height: 1.8;
    animation: fadeInUp 0.8s ease-out 0.4s both;
}

.mobile-br { display: none; }

.hero-actions {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 48px;
    animation: fadeInUp 0.8s ease-out 0.6s both;
}

.hero-btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 16px 32px;
    font-weight: 700;
    font-size: 1rem;
    border-radius: var(--radius-full);
    transition: all var(--duration-normal) var(--ease-bounce);
    font-family: var(--font-heading);
}

.primary-btn {
    background: white;
    color: var(--primary);
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.15);
}

.primary-btn:hover {
    transform: translateY(-4px) scale(1.03);
    box-shadow: 0 16px 40px rgba(0, 0, 0, 0.2);
}

.secondary-btn {
    background: rgba(255, 255, 255, 0.15);
    color: white;
    border: 2px solid rgba(255, 255, 255, 0.3);
    backdrop-filter: blur(10px);
}

.secondary-btn:hover {
    background: rgba(255, 255, 255, 0.25);
    border-color: rgba(255, 255, 255, 0.5);
    transform: translateY(-4px);
}

.hero-stats {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 24px;
    animation: fadeInUp 0.8s ease-out 0.8s both;
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    color: white;
}

.stat-number {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 700;
    display: flex;
    align-items: center;
}

.stat-label {
    font-size: 0.8rem;
    opacity: 0.7;
    font-weight: 500;
}

.stat-divider {
    width: 1px;
    height: 36px;
    background: rgba(255, 255, 255, 0.2);
}

/* Scroll indicator */
.scroll-indicator {
    position: absolute;
    bottom: 32px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 2;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    color: rgba(255, 255, 255, 0.6);
    animation: fadeInUp 1s ease-out 1.2s both;
}

.scroll-text {
    font-size: 0.75rem;
    font-weight: 500;
    letter-spacing: 1px;
}

.scroll-arrow {
    animation: scrollBounce 2s ease-in-out infinite;
}

@keyframes scrollBounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(8px); }
}

@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(24px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInDown {
    from { opacity: 0; transform: translateY(-16px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ========== Section Headers ========== */
.section-header {
    text-align: center;
    margin-bottom: 64px;
}

.section-tag {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 20px;
    background: var(--primary-bg);
    color: var(--primary);
    font-size: 0.85rem;
    font-weight: 700;
    border-radius: var(--radius-full);
    margin-bottom: 16px;
    font-family: var(--font-heading);
}

.section-title {
    font-size: clamp(2rem, 4vw, 2.8rem);
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text);
}

.section-desc {
    font-size: 1.05rem;
    color: var(--text-secondary);
    max-width: 520px;
    margin: 0 auto;
}

/* Login hint badge */
.login-hint {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    margin-top: 16px;
    padding: 10px 22px;
    background: linear-gradient(135deg, rgba(249, 115, 22, 0.08), rgba(79, 70, 229, 0.08));
    border: 1px solid rgba(249, 115, 22, 0.15);
    border-radius: var(--radius-full);
    font-size: 0.88rem;
    color: var(--text-secondary);
    animation: fadeInUp 0.6s ease-out 0.3s both;
}

.login-hint svg {
    color: var(--accent);
    flex-shrink: 0;
}

.login-hint strong {
    color: var(--accent-dark);
    font-weight: 700;
}

/* ========== Class Cards Section ========== */
.classes-section {
    background: var(--bg);
    overflow: hidden;
}

.section-deco {
    position: absolute;
    inset: 0;
    pointer-events: none;
    z-index: 0;
}

.deco-circle {
    position: absolute;
    border-radius: 50%;
    opacity: 0.04;
}

.deco-1 {
    width: 500px;
    height: 500px;
    background: var(--primary);
    top: -200px;
    right: -200px;
}

.deco-2 {
    width: 400px;
    height: 400px;
    background: var(--accent);
    bottom: -150px;
    left: -150px;
}

.class-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
    position: relative;
    z-index: 1;
}

/* ========== Class Card ========== */
.class-card {
    position: relative;
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: all 0.45s var(--ease-bounce);
    border: 2px solid var(--border-light);
    cursor: default;
}

.class-card:hover {
    transform: translateY(-12px) scale(1.02);
    border-color: transparent;
}

/* Shimmer effect on hover */
.card-shimmer {
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
    z-index: 2;
    pointer-events: none;
    transition: none;
}

.class-card:hover .card-shimmer {
    animation: shimmer 0.8s ease-out;
}

@keyframes shimmer {
    to { left: 100%; }
}

/* Glow effect */
.card-glow {
    position: absolute;
    bottom: -50%;
    left: 10%;
    right: 10%;
    height: 60%;
    border-radius: 50%;
    opacity: 0;
    transition: opacity 0.45s;
    pointer-events: none;
    z-index: 0;
    filter: blur(30px);
}

.class-card:hover .card-glow { opacity: 1; }

.class-card[data-class="1"] .card-glow { background: var(--class-1); }
.class-card[data-class="2"] .card-glow { background: var(--class-2); }
.class-card[data-class="3"] .card-glow { background: var(--class-3); }
.class-card[data-class="4"] .card-glow { background: var(--class-4); }
.class-card[data-class="5"] .card-glow { background: var(--class-5); }
.class-card[data-class="6"] .card-glow { background: var(--class-6); }

/* Hover shadows */
.class-card[data-class="1"]:hover { box-shadow: 0 20px 50px rgba(99, 102, 241, 0.28); }
.class-card[data-class="2"]:hover { box-shadow: 0 20px 50px rgba(239, 68, 68, 0.28); }
.class-card[data-class="3"]:hover { box-shadow: 0 20px 50px rgba(16, 185, 129, 0.28); }
.class-card[data-class="4"]:hover { box-shadow: 0 20px 50px rgba(245, 158, 11, 0.28); }
.class-card[data-class="5"]:hover { box-shadow: 0 20px 50px rgba(59, 130, 246, 0.28); }
.class-card[data-class="6"]:hover { box-shadow: 0 20px 50px rgba(139, 92, 246, 0.28); }

/* Background decoration */
.card-bg-deco {
    position: absolute;
    top: -30px;
    right: -30px;
    width: 140px;
    height: 140px;
    transition: all 0.45s;
    z-index: 0;
}

.class-card:hover .card-bg-deco {
    transform: scale(1.5) rotate(15deg);
}

.class-card[data-class="1"] .card-bg-deco { color: var(--class-1); }
.class-card[data-class="2"] .card-bg-deco { color: var(--class-2); }
.class-card[data-class="3"] .card-bg-deco { color: var(--class-3); }
.class-card[data-class="4"] .card-bg-deco { color: var(--class-4); }
.class-card[data-class="5"] .card-bg-deco { color: var(--class-5); }
.class-card[data-class="6"] .card-bg-deco { color: var(--class-6); }

/* Card accent bar — rainbow gradient */
.card-accent {
    height: 5px;
    transition: height var(--duration-normal);
}

.class-card:hover .card-accent { height: 7px; }

.class-card[data-class="1"] .card-accent { background: linear-gradient(90deg, var(--class-1), var(--class-1-light), #FFD93D); }
.class-card[data-class="2"] .card-accent { background: linear-gradient(90deg, var(--class-2), var(--class-2-light), var(--accent)); }
.class-card[data-class="3"] .card-accent { background: linear-gradient(90deg, var(--class-3), var(--class-3-light), var(--class-5)); }
.class-card[data-class="4"] .card-accent { background: linear-gradient(90deg, var(--class-4), var(--class-4-light), var(--class-2)); }
.class-card[data-class="5"] .card-accent { background: linear-gradient(90deg, var(--class-5), var(--class-5-light), var(--class-1)); }
.class-card[data-class="6"] .card-accent { background: linear-gradient(90deg, var(--class-6), var(--class-6-light), #FF6B9D); }

.card-content {
    padding: 32px 28px;
    position: relative;
    z-index: 1;
}

.card-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 20px;
}

.card-icon {
    width: 60px;
    height: 60px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.6rem;
    font-weight: 700;
    color: white;
    font-family: var(--font-heading);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.15);
    transition: transform var(--duration-normal) var(--ease-bounce);
}

.class-card:hover .card-icon {
    transform: rotate(-8deg) scale(1.1);
}

.class-card[data-class="1"] .card-icon { background: linear-gradient(135deg, var(--class-1), var(--class-1-light)); }
.class-card[data-class="2"] .card-icon { background: linear-gradient(135deg, var(--class-2), var(--class-2-light)); }
.class-card[data-class="3"] .card-icon { background: linear-gradient(135deg, var(--class-3), var(--class-3-light)); }
.class-card[data-class="4"] .card-icon { background: linear-gradient(135deg, var(--class-4), var(--class-4-light)); }
.class-card[data-class="5"] .card-icon { background: linear-gradient(135deg, var(--class-5), var(--class-5-light)); }
.class-card[data-class="6"] .card-icon { background: linear-gradient(135deg, var(--class-6), var(--class-6-light)); }

.card-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 5px 16px;
    border-radius: var(--radius-full);
    font-size: 0.8rem;
    font-weight: 700;
    letter-spacing: 0.5px;
    font-family: var(--font-heading);
}

.class-card[data-class="1"] .card-badge { background: rgba(99, 102, 241, 0.1); color: var(--class-1); }
.class-card[data-class="2"] .card-badge { background: rgba(239, 68, 68, 0.1); color: var(--class-2); }
.class-card[data-class="3"] .card-badge { background: rgba(16, 185, 129, 0.1); color: var(--class-3); }
.class-card[data-class="4"] .card-badge { background: rgba(245, 158, 11, 0.1); color: var(--class-4); }
.class-card[data-class="5"] .card-badge { background: rgba(59, 130, 246, 0.1); color: var(--class-5); }
.class-card[data-class="6"] .card-badge { background: rgba(139, 92, 246, 0.1); color: var(--class-6); }

.card-title {
    font-size: 1.4rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.card-desc {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 24px;
    line-height: 1.6;
}

.card-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 13px 28px;
    border-radius: var(--radius-full);
    font-weight: 700;
    font-size: 0.9rem;
    color: white;
    transition: all var(--duration-normal) var(--ease-bounce);
    position: relative;
    overflow: hidden;
    font-family: var(--font-heading);
    min-height: 44px; /* Touch target */
}

.btn-arrow {
    opacity: 0;
    transform: translateX(-8px);
    transition: all var(--duration-fast);
}

.card-btn:hover .btn-arrow {
    opacity: 1;
    transform: translateX(0);
}

.card-btn::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, rgba(255,255,255,0.25), transparent);
    opacity: 0;
    transition: opacity var(--duration-fast);
}

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

.class-card[data-class="1"] .card-btn { background: linear-gradient(135deg, var(--class-1), var(--class-1-light)); }
.class-card[data-class="2"] .card-btn { background: linear-gradient(135deg, var(--class-2), var(--class-2-light)); }
.class-card[data-class="3"] .card-btn { background: linear-gradient(135deg, var(--class-3), var(--class-3-light)); }
.class-card[data-class="4"] .card-btn { background: linear-gradient(135deg, var(--class-4), var(--class-4-light)); }
.class-card[data-class="5"] .card-btn { background: linear-gradient(135deg, var(--class-5), var(--class-5-light)); }
.class-card[data-class="6"] .card-btn { background: linear-gradient(135deg, var(--class-6), var(--class-6-light)); }

.card-btn:hover {
    transform: translateY(-3px) scale(1.05);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
}

/* ========== Guide Section ========== */
.guide-section {
    background: var(--bg-white);
}

.steps-timeline {
    display: flex;
    flex-direction: column;
    gap: 0;
    max-width: 600px;
    margin: 0 auto 56px;
    position: relative;
}

.timeline-line {
    position: absolute;
    left: 24px;
    top: 30px;
    bottom: 30px;
    width: 3px;
    background: linear-gradient(180deg, var(--primary), var(--accent));
    border-radius: 2px;
}

.step-card {
    display: flex;
    gap: 24px;
    padding: 24px 0;
    position: relative;
}

.step-indicator {
    flex-shrink: 0;
    width: 50px;
    display: flex;
    justify-content: center;
}

.step-dot {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: var(--primary);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-family: var(--font-heading);
    font-weight: 700;
    font-size: 1.1rem;
    box-shadow: 0 4px 15px rgba(79, 70, 229, 0.3);
    transition: all var(--duration-normal) var(--ease-bounce);
    position: relative;
    z-index: 1;
}

.step-card:hover .step-dot {
    transform: scale(1.15);
    box-shadow: 0 6px 25px rgba(79, 70, 229, 0.4);
}

.step-card[data-step="2"] .step-dot { background: var(--info); box-shadow: 0 4px 15px rgba(59, 130, 246, 0.3); }
.step-card[data-step="3"] .step-dot { background: var(--accent); box-shadow: 0 4px 15px rgba(249, 115, 22, 0.3); }

.step-body {
    flex: 1;
    background: var(--bg);
    border-radius: var(--radius-md);
    padding: 28px 24px;
    transition: all var(--duration-normal);
    border: 1px solid transparent;
}

.step-card:hover .step-body {
    background: var(--bg-white);
    border-color: var(--border);
    box-shadow: var(--shadow-sm);
    transform: translateX(4px);
}

.step-icon-wrap {
    color: var(--primary);
    margin-bottom: 12px;
}

.step-card[data-step="2"] .step-icon-wrap { color: var(--info); }
.step-card[data-step="3"] .step-icon-wrap { color: var(--accent); }

.step-body h3 {
    font-size: 1.15rem;
    font-weight: 700;
    margin-bottom: 6px;
}

.step-body p {
    font-size: 0.92rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Tips box */
.tips-box {
    background: linear-gradient(135deg, var(--primary-bg), rgba(249, 115, 22, 0.04));
    border: 1px solid rgba(79, 70, 229, 0.12);
    border-radius: var(--radius-lg);
    padding: 36px 40px;
    max-width: 700px;
    margin: 0 auto;
}

.tips-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 20px;
    color: var(--primary);
}

.tips-header h3 {
    font-size: 1.1rem;
    color: var(--primary-dark);
}

.tips-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.tips-list li {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    font-size: 0.92rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.tips-list li svg {
    flex-shrink: 0;
    color: var(--success);
    margin-top: 3px;
}

.tips-list li strong {
    color: var(--text);
}

/* ========== Contact Section ========== */
.contact-section {
    background: var(--bg);
}

.contact-card {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
    color: white;
    border-radius: var(--radius-xl);
    padding: 72px 48px;
    text-align: center;
    max-width: 750px;
    margin: 0 auto;
    position: relative;
    overflow: hidden;
}

.contact-deco {
    position: absolute;
    inset: 0;
    pointer-events: none;
}

.contact-circle {
    position: absolute;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.08);
}

.c1 { width: 200px; height: 200px; top: -60px; right: -60px; }
.c2 { width: 150px; height: 150px; bottom: -40px; left: -40px; }

.contact-inner {
    position: relative;
    z-index: 1;
}

.contact-inner h2 {
    font-size: 2rem;
    margin-bottom: 12px;
    margin-top: 16px;
}

.contact-inner > p {
    opacity: 0.85;
    margin-bottom: 36px;
    font-size: 1.05rem;
}

.contact-info {
    display: flex;
    gap: 20px;
    justify-content: center;
    flex-wrap: wrap;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 10px;
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(10px);
    padding: 14px 28px;
    border-radius: var(--radius-full);
    font-size: 0.95rem;
    font-weight: 500;
    transition: all var(--duration-normal);
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: white;
    min-height: 44px;
}

.contact-item:hover {
    background: rgba(255, 255, 255, 0.25);
    transform: translateY(-2px);
}

/* ========== Footer ========== */
.footer {
    background: var(--text);
    color: rgba(255, 255, 255, 0.5);
    padding: 28px 0;
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: 8px;
    color: rgba(255, 255, 255, 0.7);
    font-weight: 600;
    font-size: 0.9rem;
    font-family: var(--font-heading);
}

.footer-copy {
    font-size: 0.8rem;
}

.footer-made {
    font-size: 0.85rem;
    color: rgba(255, 255, 255, 0.6);
    margin-top: 4px;
}

.footer-made a {
    color: rgba(255, 255, 255, 0.85);
    font-weight: 700;
    transition: color var(--duration-fast);
    text-decoration: underline;
    text-decoration-color: rgba(255, 255, 255, 0.3);
    text-underline-offset: 3px;
}

.footer-made a:hover {
    color: white;
    text-decoration-color: rgba(255, 255, 255, 0.7);
}

/* ========== Back to Top ========== */
.back-to-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--primary);
    color: white;
    border: none;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-md);
    z-index: 900;
    opacity: 0;
    visibility: hidden;
    transform: translateY(16px);
    transition: all var(--duration-normal) var(--ease-bounce);
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    background: var(--primary-dark);
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

/* ========== Modal ========== */
.modal {
    position: fixed;
    inset: 0;
    z-index: 2000;
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-overlay {
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
}

.modal-content {
    position: relative;
    background: white;
    border-radius: var(--radius-lg);
    padding: 48px 40px;
    max-width: 460px;
    width: 90%;
    text-align: center;
    box-shadow: var(--shadow-lg);
    animation: modalIn 0.3s ease-out;
}

@keyframes modalIn {
    from { opacity: 0; transform: scale(0.9) translateY(20px); }
    to { opacity: 1; transform: scale(1) translateY(0); }
}

.modal-icon {
    color: var(--primary);
    margin-bottom: 16px;
}

.modal-content h3 {
    font-size: 1.3rem;
    margin-bottom: 12px;
}

.modal-content p {
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.modal-content code {
    background: var(--primary-bg);
    padding: 3px 10px;
    border-radius: 6px;
    font-size: 0.88rem;
    color: var(--primary);
    font-weight: 600;
}

.modal-hint {
    font-size: 0.85rem !important;
    color: var(--text-muted) !important;
    margin-bottom: 24px !important;
}

.modal-close-btn {
    padding: 14px 36px;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: var(--radius-full);
    font-size: 0.95rem;
    font-weight: 700;
    font-family: var(--font-heading);
    transition: all var(--duration-normal) var(--ease-bounce);
    min-height: 44px;
}

.modal-close-btn:hover {
    background: var(--primary-dark);
    transform: scale(1.05);
}

/* ========== Responsive — Tablet ========== */
@media (max-width: 1024px) {
    .class-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 20px;
    }
}

/* ========== Responsive — Mobile ========== */
@media (max-width: 768px) {
    .section { padding: 72px 0; }

    .nav-links {
        display: none;
        position: absolute;
        top: 68px;
        left: 0;
        right: 0;
        background: rgba(255, 255, 255, 0.98);
        backdrop-filter: blur(20px);
        flex-direction: column;
        padding: 16px 24px;
        gap: 4px;
        border-bottom: 1px solid var(--border);
        box-shadow: var(--shadow-md);
    }

    .nav-links.active { display: flex; }

    .nav-link {
        padding: 14px 16px;
        border-radius: var(--radius-sm);
        font-size: 1rem;
    }

    .nav-toggle { display: flex; }

    .mobile-br { display: block; }

    .hero-subtitle { font-size: 1rem; }

    .hero-stats { gap: 16px; }
    .stat-number { font-size: 1.2rem; }

    .class-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 16px;
    }

    .card-content { padding: 24px 20px; }
    .card-icon { width: 48px; height: 48px; font-size: 1.3rem; }
    .card-title { font-size: 1.15rem; }
    .card-desc { font-size: 0.82rem; margin-bottom: 18px; }
    .card-btn { padding: 11px 22px; font-size: 0.82rem; }
    .btn-arrow { display: none; }

    .timeline-line { left: 17px; }
    .step-indicator { width: 36px; }
    .step-dot { width: 36px; height: 36px; font-size: 0.9rem; }
    .step-body { padding: 20px 18px; }
    .step-body h3 { font-size: 1.05rem; }

    .section-header { margin-bottom: 44px; }

    .tips-box { padding: 24px 20px; }

    .contact-card { padding: 48px 24px; }
    .contact-info { flex-direction: column; align-items: center; }

    .scroll-indicator { display: none; }

    .qr-btn { opacity: 1; bottom: 20px; right: 20px; }

    .toast { bottom: 16px; }
}

/* ========== Responsive — Small Phone ========== */
@media (max-width: 480px) {
    .hero-btn { padding: 14px 24px; font-size: 0.92rem; }

    .class-grid {
        grid-template-columns: 1fr;
        max-width: 380px;
        margin: 0 auto;
    }

    .card-content { padding: 28px 24px; }
    .card-icon { width: 56px; height: 56px; font-size: 1.5rem; }
    .card-title { font-size: 1.3rem; }
    .card-desc { font-size: 0.88rem; }
    .card-btn {
        padding: 13px 24px;
        font-size: 0.9rem;
        width: 100%;
        justify-content: center;
    }

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

    .hero-btn { width: 100%; max-width: 280px; justify-content: center; }
}

/* ========== Scroll Animations ========== */
.class-card,
.step-card,
.tips-box {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

.class-card.visible,
.step-card.visible,
.tips-box.visible {
    opacity: 1;
    transform: translateY(0);
}

.class-card:nth-child(1) { transition-delay: 0s; }
.class-card:nth-child(2) { transition-delay: 0.1s; }
.class-card:nth-child(3) { transition-delay: 0.2s; }
.class-card:nth-child(4) { transition-delay: 0.3s; }
.class-card:nth-child(5) { transition-delay: 0.4s; }
.class-card:nth-child(6) { transition-delay: 0.5s; }

.step-card:nth-child(2) { transition-delay: 0.15s; }
.step-card:nth-child(3) { transition-delay: 0.3s; }
.step-card:nth-child(4) { transition-delay: 0.45s; }

/* ========== Toast 通知 ========== */
.toast {
    position: fixed;
    bottom: 32px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    z-index: 3000;
    background: var(--text);
    color: white;
    border-radius: var(--radius-md);
    padding: 16px 24px;
    display: flex;
    align-items: center;
    gap: 14px;
    box-shadow: 0 16px 48px rgba(0, 0, 0, 0.2);
    opacity: 0;
    visibility: hidden;
    transition: all 0.4s var(--ease-bounce);
    max-width: 420px;
    width: calc(100% - 48px);
}

.toast.visible {
    opacity: 1;
    visibility: visible;
    transform: translateX(-50%) translateY(0);
}

.toast-icon {
    flex-shrink: 0;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: var(--success);
    display: flex;
    align-items: center;
    justify-content: center;
}

.toast-icon svg {
    color: white;
}

.toast-text {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.toast-text strong {
    font-size: 0.92rem;
    font-weight: 700;
}

.toast-text span {
    font-size: 0.8rem;
    opacity: 0.7;
}

/* ========== QR Code Button ========== */
.qr-btn {
    position: absolute;
    bottom: 28px;
    right: 28px;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    border: 2px solid var(--border);
    background: var(--bg);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
    transition: all var(--duration-normal) var(--ease-bounce);
    z-index: 3;
    opacity: 0;
}

.class-card:hover .qr-btn {
    opacity: 1;
}

.qr-btn:hover {
    border-color: var(--primary);
    color: var(--primary);
    background: var(--primary-bg);
    transform: scale(1.15);
}

/* ========== QR Code Modal ========== */
.qr-modal-content {
    max-width: 400px;
    padding: 40px 32px;
}

.qr-close {
    position: absolute;
    top: 12px;
    right: 16px;
    width: 36px;
    height: 36px;
    border: none;
    background: none;
    font-size: 1.5rem;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: all var(--duration-fast);
}

.qr-close:hover {
    background: var(--bg-section);
    color: var(--text);
}

.qr-modal-title {
    font-size: 1.2rem;
    margin-bottom: 4px;
}

.qr-modal-desc {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-bottom: 24px;
}

.qr-canvas {
    display: flex;
    justify-content: center;
    padding: 20px;
    background: white;
    border-radius: var(--radius-md);
    border: 1px solid var(--border);
    margin-bottom: 12px;
}

.qr-class-name {
    font-family: var(--font-heading);
    font-weight: 700;
    font-size: 1.1rem;
    color: var(--primary);
    margin-bottom: 20px;
}

.qr-actions {
    display: flex;
    gap: 10px;
    justify-content: center;
}

.qr-action-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 10px 20px;
    border-radius: var(--radius-full);
    border: none;
    font-size: 0.85rem;
    font-weight: 600;
    font-family: var(--font-heading);
    transition: all var(--duration-normal) var(--ease-bounce);
    background: var(--primary);
    color: white;
    min-height: 40px;
}

.qr-action-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
}

.qr-action-btn.secondary {
    background: var(--bg-section);
    color: var(--text-secondary);
}

.qr-action-btn.secondary:hover {
    background: var(--border);
}

/* ========== Print Styles ========== */
@media print {
    .navbar, .hero-bg, .floating-crafts, .back-to-top,
    .card-shimmer, .card-glow, .scroll-indicator, .loader,
    .toast, .qr-btn, #qrModal { display: none; }
    .hero { min-height: auto; padding: 40px 0; }
    .class-card { break-inside: avoid; }
}