/* ========================================
   Next-Gen CAPTCHAs - Modern Redesign CSS
   Vibrant gradients, glassmorphism, animations
   ======================================== */

:root {
    /* New Gradient Colors */
    --gradient-start: #667eea;
    --gradient-mid: #764ba2;
    --gradient-end: #f093fb;
    --gradient-accent: #a855f7;

    /* Accent Colors */
    --accent-cyan: #00d4ff;
    --accent-teal: #00f5d4;
    --accent-pink: #ff6b9d;
    --accent-orange: #ff9f43;

    /* Primary Colors */
    --color-primary: #6366f1;
    --color-primary-light: #818cf8;
    --color-primary-dark: #4f46e5;

    /* Semantic Colors */
    --color-human: #10b981;
    --color-human-light: #34d399;
    --color-human-glow: rgba(16, 185, 129, 0.4);
    --color-ai: #ef4444;
    --color-ai-light: #f87171;
    --color-ai-glow: rgba(239, 68, 68, 0.4);

    /* Neutrals */
    --color-bg: #0f0f1a;
    --color-bg-alt: #1a1a2e;
    --color-bg-card: #16162a;
    --color-text: #f1f5f9;
    --color-text-light: #94a3b8;
    --color-text-muted: #64748b;
    --color-border: rgba(255, 255, 255, 0.1);

    /* Glassmorphism */
    --glass-bg: rgba(255, 255, 255, 0.05);
    --glass-bg-hover: rgba(255, 255, 255, 0.1);
    --glass-border: rgba(255, 255, 255, 0.1);
    --glass-border-hover: rgba(255, 255, 255, 0.2);

    /* Typography */
    --font-heading: 'Space Grotesk', sans-serif;
    --font-body: 'Inter', sans-serif;

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

    /* Borders */
    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
    --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.6);
    --shadow-glow: 0 0 40px rgba(102, 126, 234, 0.3);
    --shadow-glow-pink: 0 0 40px rgba(240, 147, 251, 0.3);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    font-size: 16px;
    line-height: 1.7;
    color: var(--color-text);
    background-color: var(--color-bg);
    overflow-x: hidden;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 10px;
}

::-webkit-scrollbar-track {
    background: var(--color-bg);
}

::-webkit-scrollbar-thumb {
    background: linear-gradient(180deg, var(--gradient-start), var(--gradient-mid));
    border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
    background: linear-gradient(180deg, var(--gradient-mid), var(--gradient-end));
}

/* Selection */
::selection {
    background: var(--gradient-mid);
    color: white;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 600;
    line-height: 1.3;
}

h1 { font-size: 3.5rem; }
h2 { font-size: 2.25rem; margin-bottom: var(--spacing-lg); }
h3 { font-size: 1.25rem; }

p { margin-bottom: var(--spacing-md); }

a {
    color: var(--accent-cyan);
    text-decoration: none;
    transition: all 0.3s ease;
}

a:hover {
    color: var(--accent-teal);
    text-shadow: 0 0 20px var(--accent-cyan);
}

/* ========================================
   Keyframe Animations
   ======================================== */

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

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-20px); }
}

@keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.8; transform: scale(1.05); }
}

@keyframes glow {
    0%, 100% { box-shadow: 0 0 20px rgba(102, 126, 234, 0.4); }
    50% { box-shadow: 0 0 40px rgba(240, 147, 251, 0.6); }
}

@keyframes slideUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes slideIn {
    from { opacity: 0; transform: translateX(-20px); }
    to { opacity: 1; transform: translateX(0); }
}

@keyframes scaleIn {
    from { opacity: 0; transform: scale(0.9); }
    to { opacity: 1; transform: scale(1); }
}

@keyframes shimmer {
    0% { background-position: -200% 0; }
    100% { background-position: 200% 0; }
}

@keyframes rotateGradient {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

@keyframes barGrow {
    from { height: 0; }
    to { height: var(--target-height); }
}

@keyframes orbFloat1 {
    0%, 100% { transform: translate(0, 0) scale(1); }
    25% { transform: translate(50px, -30px) scale(1.1); }
    50% { transform: translate(20px, 40px) scale(0.9); }
    75% { transform: translate(-30px, 20px) scale(1.05); }
}

@keyframes orbFloat2 {
    0%, 100% { transform: translate(0, 0) scale(1); }
    25% { transform: translate(-40px, 30px) scale(0.95); }
    50% { transform: translate(30px, -50px) scale(1.1); }
    75% { transform: translate(50px, 10px) scale(1); }
}

@keyframes orbFloat3 {
    0%, 100% { transform: translate(0, 0) scale(1.05); }
    33% { transform: translate(-60px, -40px) scale(0.9); }
    66% { transform: translate(40px, 60px) scale(1.15); }
}

/* Scroll reveal classes */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

.reveal.active {
    opacity: 1;
    transform: translateY(0);
}

.reveal-left {
    opacity: 0;
    transform: translateX(-30px);
    transition: all 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

.reveal-left.active {
    opacity: 1;
    transform: translateX(0);
}

.reveal-scale {
    opacity: 0;
    transform: scale(0.9);
    transition: all 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

.reveal-scale.active {
    opacity: 1;
    transform: scale(1);
}

/* ========================================
   Sticky Navigation
   ======================================== */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: var(--spacing-md) 0;
    background: rgba(15, 15, 26, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--glass-border);
    transform: translateY(-100%);
    transition: transform 0.3s ease;
}

.nav.visible {
    transform: translateY(0);
}

.nav .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    gap: var(--spacing-lg);
}

.nav-links a {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--color-text-light);
    transition: all 0.3s ease;
    position: relative;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--gradient-start), var(--gradient-end));
    transition: width 0.3s ease;
}

.nav-links a:hover {
    color: var(--color-text);
    text-shadow: none;
}

.nav-links a:hover::after {
    width: 100%;
}

/* ========================================
   Hero Section
   ======================================== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: var(--spacing-4xl) 0;
    text-align: center;
    overflow: hidden;
}

/* Animated gradient background */
.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(
        135deg,
        var(--gradient-start) 0%,
        var(--gradient-mid) 25%,
        var(--color-bg) 50%,
        var(--gradient-mid) 75%,
        var(--gradient-end) 100%
    );
    background-size: 400% 400%;
    animation: gradientShift 15s ease infinite;
    z-index: -2;
}

/* Floating orbs */
.hero-orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.5;
    z-index: -1;
}

.hero-orb-1 {
    width: 400px;
    height: 400px;
    background: var(--gradient-start);
    top: 10%;
    left: 10%;
    animation: orbFloat1 20s ease-in-out infinite;
}

.hero-orb-2 {
    width: 300px;
    height: 300px;
    background: var(--gradient-end);
    top: 60%;
    right: 10%;
    animation: orbFloat2 25s ease-in-out infinite;
}

.hero-orb-3 {
    width: 250px;
    height: 250px;
    background: var(--accent-cyan);
    bottom: 20%;
    left: 30%;
    animation: orbFloat3 18s ease-in-out infinite;
}

.hero .container {
    position: relative;
    z-index: 1;
}

.hero .title {
    font-size: 4rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    letter-spacing: -0.02em;
    background: linear-gradient(135deg, #fff 0%, var(--accent-cyan) 50%, var(--gradient-end) 100%);
    background-size: 200% 200%;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: gradientShift 5s ease infinite;
}

.hero .subtitle {
    font-size: 1.35rem;
    opacity: 0.9;
    max-width: 750px;
    margin: 0 auto var(--spacing-lg);
    font-weight: 400;
    color: var(--color-text-light);
}

/* Authors */
.authors {
    margin-bottom: var(--spacing-sm);
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--spacing-xs) var(--spacing-md);
}

.author {
    font-weight: 500;
    font-size: 1.05rem;
    color: var(--color-text);
}

.author sup {
    font-size: 0.7em;
    color: var(--accent-cyan);
}

.affiliations {
    margin-bottom: var(--spacing-xl);
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--spacing-xs) var(--spacing-lg);
}

.affiliation {
    font-size: 0.85rem;
    color: var(--color-text-light);
}

.affiliation sup {
    color: var(--accent-cyan);
}

.affiliation.note {
    font-style: italic;
    color: var(--color-text-muted);
}

/* Hero Stats - Glassmorphism */
.hero-stats {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: var(--spacing-xl);
    margin: var(--spacing-3xl) 0;
    flex-wrap: wrap;
}

.stat-card {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl) var(--spacing-2xl);
    min-width: 200px;
    border: 1px solid var(--glass-border);
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
}

.stat-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, transparent 0%, rgba(255,255,255,0.05) 100%);
    z-index: -1;
}

.stat-card:hover {
    transform: translateY(-8px) scale(1.02);
    border-color: var(--glass-border-hover);
}

.stat-card.human {
    background: linear-gradient(135deg, rgba(16, 185, 129, 0.15), rgba(16, 185, 129, 0.05));
    border-color: rgba(16, 185, 129, 0.3);
    box-shadow: 0 8px 32px rgba(16, 185, 129, 0.2);
}

.stat-card.human:hover {
    box-shadow: 0 16px 48px rgba(16, 185, 129, 0.3);
}

.stat-card.ai {
    background: linear-gradient(135deg, rgba(239, 68, 68, 0.15), rgba(239, 68, 68, 0.05));
    border-color: rgba(239, 68, 68, 0.3);
    box-shadow: 0 8px 32px rgba(239, 68, 68, 0.2);
}

.stat-card.ai:hover {
    box-shadow: 0 16px 48px rgba(239, 68, 68, 0.3);
}

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

.stat-value {
    font-family: var(--font-heading);
    font-size: 3rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--color-text), var(--color-text-light));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-card.human .stat-value {
    background: linear-gradient(135deg, var(--color-human), var(--color-human-light));
    -webkit-background-clip: text;
    background-clip: text;
}

.stat-card.ai .stat-value {
    background: linear-gradient(135deg, var(--color-ai), var(--color-ai-light));
    -webkit-background-clip: text;
    background-clip: text;
}

.stat-label {
    font-size: 0.9rem;
    color: var(--color-text-light);
    margin-top: var(--spacing-xs);
}

.stat-detail {
    font-size: 0.8rem;
    color: var(--color-text-muted);
    margin-top: var(--spacing-xs);
}

/* Gap indicator */
.stat-vs {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.gap-arrow {
    font-size: 0.9rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    color: white;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-full);
    animation: pulse 2s ease-in-out infinite;
    box-shadow: 0 4px 20px rgba(102, 126, 234, 0.4);
}

/* Hero Links */
.hero-links {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-xl);
    border-radius: var(--radius-full);
    font-weight: 600;
    font-size: 0.95rem;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border: 2px solid transparent;
    cursor: pointer;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
    transition: left 0.5s ease;
}

.btn:hover::before {
    left: 100%;
}

.btn-primary {
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-mid));
    color: white;
    box-shadow: 0 4px 20px rgba(102, 126, 234, 0.4);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 30px rgba(102, 126, 234, 0.6);
    color: white;
}

.btn-secondary {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    color: white;
    border-color: var(--glass-border);
}

.btn-secondary:hover {
    background: var(--glass-bg-hover);
    border-color: var(--glass-border-hover);
    transform: translateY(-3px);
    color: white;
}

.btn-large {
    padding: var(--spacing-lg) var(--spacing-3xl);
    font-size: 1.1rem;
}

/* ========================================
   Abstract Section
   ======================================== */
.abstract {
    background: var(--color-bg-alt);
    padding: var(--spacing-4xl) 0;
    position: relative;
}

.abstract::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: linear-gradient(180deg, var(--gradient-start), var(--gradient-end));
}

.abstract h2 {
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-align: left;
}

.abstract p {
    max-width: 900px;
    font-size: 1.15rem;
    color: var(--color-text-light);
    line-height: 1.8;
}

.abstract strong {
    color: var(--accent-cyan);
    font-weight: 600;
}

.abstract em {
    color: var(--gradient-end);
    font-style: italic;
}

/* ========================================
   Section Common Styles
   ======================================== */
section {
    padding: var(--spacing-4xl) 0;
    position: relative;
}

section h2 {
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-align: center;
}

.section-desc {
    text-align: center;
    color: var(--color-text-muted);
    max-width: 600px;
    margin: 0 auto var(--spacing-3xl);
    font-size: 1.1rem;
}

/* ========================================
   Results Section
   ======================================== */
.results {
    background: var(--color-bg);
}

.results h2,
.results .section-desc {
    padding-left: var(--spacing-xl);
}

.results-chart {
    margin: var(--spacing-3xl) 0;
}

.bar-chart {
    display: flex;
    justify-content: center;
    align-items: flex-end;
    gap: var(--spacing-xl);
    height: 350px;
    padding: var(--spacing-2xl);
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-xl);
    border: 1px solid var(--glass-border);
    position: relative;
}

/* Chart grid lines */
.bar-chart::before {
    content: '';
    position: absolute;
    top: var(--spacing-2xl);
    left: var(--spacing-2xl);
    right: var(--spacing-2xl);
    bottom: 60px;
    background: repeating-linear-gradient(
        0deg,
        transparent,
        transparent calc(20% - 1px),
        rgba(255,255,255,0.05) calc(20% - 1px),
        rgba(255,255,255,0.05) 20%
    );
    pointer-events: none;
}

.bar {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: flex-end;
    width: 70px;
    border-radius: var(--radius-md) var(--radius-md) 0 0;
    position: relative;
    transition: all 0.3s ease;
    cursor: pointer;
}

.bar.animated {
    animation: barGrow 1s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

.bar:hover {
    filter: brightness(1.2);
    transform: scaleX(1.1);
}

/* Individual model colors */
.bar-human {
    background: linear-gradient(180deg, #34d399, #10b981);
    box-shadow: 0 0 20px rgba(16, 185, 129, 0.5);
}

.bar-openai {
    background: linear-gradient(180deg, #74aa9c, #10a37f);
    box-shadow: 0 0 15px rgba(16, 163, 127, 0.4);
}

.bar-gemini {
    background: linear-gradient(180deg, #8ab4f8, #4285f4);
    box-shadow: 0 0 15px rgba(66, 133, 244, 0.4);
}

.bar-claude {
    background: linear-gradient(180deg, #d4a574, #cc785c);
    box-shadow: 0 0 15px rgba(204, 120, 92, 0.4);
}

.bar-doubao {
    background: linear-gradient(180deg, #6ee7b7, #14b8a6);
    box-shadow: 0 0 15px rgba(20, 184, 166, 0.4);
}

.bar-qwen {
    background: linear-gradient(180deg, #c084fc, #a855f7);
    box-shadow: 0 0 15px rgba(168, 85, 247, 0.4);
}

/* Logo on top of bar */
.bar-logo {
    position: absolute;
    top: -55px;
    width: 36px;
    height: 36px;
    object-fit: contain;
    border-radius: 50%;
    background: var(--glass-bg);
    padding: 4px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.3);
    transition: transform 0.3s ease;
}

.bar:hover .bar-logo {
    transform: scale(1.15);
}

.bar-value {
    position: absolute;
    top: -85px;
    font-weight: 700;
    font-size: 0.95rem;
    color: var(--color-text);
    text-shadow: 0 2px 10px rgba(0,0,0,0.5);
}

.bar-label {
    position: absolute;
    bottom: -50px;
    font-size: 0.75rem;
    color: var(--color-text-muted);
    text-align: center;
    width: 90px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

/* Chart Legend */
.chart-legend {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: var(--spacing-lg);
    margin-top: var(--spacing-3xl);
    padding: var(--spacing-lg);
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    border-radius: var(--radius-lg);
    border: 1px solid var(--glass-border);
}

.legend-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.legend-color {
    width: 16px;
    height: 16px;
    border-radius: var(--radius-sm);
}

.legend-human {
    background: linear-gradient(135deg, #34d399, #10b981);
}

.legend-openai {
    background: linear-gradient(135deg, #74aa9c, #10a37f);
}

.legend-gemini {
    background: linear-gradient(135deg, #8ab4f8, #4285f4);
}

.legend-claude {
    background: linear-gradient(135deg, #d4a574, #cc785c);
}

.legend-doubao {
    background: linear-gradient(135deg, #6ee7b7, #14b8a6);
}

.legend-qwen {
    background: linear-gradient(135deg, #c084fc, #a855f7);
}

.legend-label {
    font-size: 0.85rem;
    color: var(--color-text-muted);
}

/* Cost Insights */
.cost-insight {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--spacing-xl);
    margin-top: var(--spacing-3xl);
}

.insight-card {
    display: flex;
    gap: var(--spacing-lg);
    padding: var(--spacing-xl);
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-xl);
    border: 1px solid var(--glass-border);
    position: relative;
    overflow: hidden;
    transition: all 0.4s ease;
}

.insight-card::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 4px;
    background: linear-gradient(180deg, var(--gradient-start), var(--gradient-end));
}

.insight-card:hover {
    transform: translateY(-4px);
    border-color: var(--glass-border-hover);
    box-shadow: var(--shadow-glow);
}

.insight-icon {
    font-size: 2.5rem;
    animation: float 3s ease-in-out infinite;
}

.insight-title {
    font-weight: 700;
    font-size: 1.1rem;
    background: linear-gradient(135deg, var(--color-text), var(--accent-cyan));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--spacing-xs);
}

.insight-desc {
    font-size: 0.95rem;
    color: var(--color-text-light);
    line-height: 1.6;
}

.insight-desc strong {
    color: var(--accent-cyan);
}

/* ========================================
   Categories Section
   ======================================== */
.categories {
    background: var(--color-bg-alt);
}

.category-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
}

.category-card {
    background: var(--color-bg-card);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    border: 1px solid var(--glass-border);
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
}

/* Gradient border effect on hover */
.category-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    border-radius: var(--radius-xl);
    padding: 2px;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
    -webkit-mask-composite: xor;
    mask-composite: exclude;
    opacity: 0;
    transition: opacity 0.4s ease;
}

.category-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-glow);
}

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

.category-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.category-tag {
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-full);
    font-size: 0.8rem;
    font-weight: 700;
    color: white;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.category-card[data-category="G1"] .category-tag {
    background: linear-gradient(135deg, #3b82f6, #60a5fa);
    box-shadow: 0 4px 15px rgba(59, 130, 246, 0.4);
}
.category-card[data-category="G2"] .category-tag {
    background: linear-gradient(135deg, #8b5cf6, #a78bfa);
    box-shadow: 0 4px 15px rgba(139, 92, 246, 0.4);
}
.category-card[data-category="G3"] .category-tag {
    background: linear-gradient(135deg, #ec4899, #f472b6);
    box-shadow: 0 4px 15px rgba(236, 72, 153, 0.4);
}
.category-card[data-category="G4"] .category-tag {
    background: linear-gradient(135deg, #f59e0b, #fbbf24);
    box-shadow: 0 4px 15px rgba(245, 158, 11, 0.4);
}
.category-card[data-category="G5"] .category-tag {
    background: linear-gradient(135deg, #10b981, #34d399);
    box-shadow: 0 4px 15px rgba(16, 185, 129, 0.4);
}

.category-card h3 {
    color: var(--color-text);
    font-size: 1.15rem;
}

.category-card p {
    color: var(--color-text-light);
    font-size: 0.95rem;
    margin-bottom: var(--spacing-md);
    line-height: 1.6;
}

.category-examples {
    font-size: 0.85rem;
    color: var(--accent-cyan);
    font-weight: 500;
    padding-top: var(--spacing-sm);
    border-top: 1px solid var(--glass-border);
}

/* ========================================
   Gallery Section
   ======================================== */
.gallery {
    background: var(--color-bg);
}

.gallery-filters {
    display: flex;
    justify-content: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-3xl);
    flex-wrap: wrap;
}

.filter-btn {
    padding: var(--spacing-sm) var(--spacing-lg);
    border: 1px solid var(--glass-border);
    background: var(--glass-bg);
    border-radius: var(--radius-full);
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--color-text-light);
    cursor: pointer;
    transition: all 0.3s ease;
}

.filter-btn:hover {
    border-color: var(--gradient-start);
    color: var(--color-text);
    background: var(--glass-bg-hover);
}

.filter-btn.active {
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-mid));
    color: white;
    border-color: transparent;
    box-shadow: 0 4px 20px rgba(102, 126, 234, 0.4);
}

.captcha-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: var(--spacing-xl);
}

.captcha-card {
    background: var(--color-bg-card);
    border-radius: var(--radius-xl);
    overflow: hidden;
    border: 1px solid var(--glass-border);
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.captcha-card:hover {
    transform: translateY(-8px);
    border-color: var(--glass-border-hover);
    box-shadow: var(--shadow-glow);
}

.captcha-card.hidden {
    display: none;
}

.captcha-preview {
    position: relative;
    background: linear-gradient(135deg, #1a1a2e 0%, #0f0f1a 100%);
    aspect-ratio: 4/3;
    overflow: hidden;
}

.captcha-preview img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    transition: transform 0.5s ease;
}

.captcha-card:hover .captcha-preview img {
    transform: scale(1.08);
}

/* Glassmorphism overlay on hover */
.captcha-preview::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(180deg, transparent 50%, rgba(15, 15, 26, 0.8) 100%);
    opacity: 0;
    transition: opacity 0.4s ease;
}

.captcha-card:hover .captcha-preview::after {
    opacity: 1;
}

.captcha-info {
    padding: var(--spacing-lg);
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
}

.captcha-name {
    font-weight: 700;
    font-size: 1.05rem;
    color: var(--color-text);
    margin-bottom: var(--spacing-xs);
}

.captcha-desc {
    font-size: 0.9rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-md);
    line-height: 1.5;
}

.captcha-tags {
    display: flex;
    gap: var(--spacing-xs);
    flex-wrap: wrap;
}

.captcha-tag {
    font-size: 0.75rem;
    font-weight: 500;
    padding: 4px 10px;
    border-radius: var(--radius-full);
    background: var(--glass-bg-hover);
    color: var(--color-text-muted);
    border: 1px solid var(--glass-border);
}

.captcha-tag.gap-tag {
    color: white;
    border: none;
}

/* ========================================
   Demo Section
   ======================================== */
.demo {
    position: relative;
    text-align: center;
    overflow: hidden;
    padding: var(--spacing-4xl) 0;
}

.demo::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(
        135deg,
        var(--gradient-start) 0%,
        var(--gradient-mid) 50%,
        var(--gradient-end) 100%
    );
    background-size: 200% 200%;
    animation: gradientShift 10s ease infinite;
    z-index: -1;
}

/* Geometric pattern overlay */
.demo::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: radial-gradient(circle at 2px 2px, rgba(255,255,255,0.1) 1px, transparent 0);
    background-size: 40px 40px;
    z-index: 0;
}

.demo .container {
    position: relative;
    z-index: 1;
}

.demo h2 {
    color: white;
    -webkit-text-fill-color: white;
    background: none;
    font-size: 2.5rem;
}

.demo .section-desc {
    color: rgba(255,255,255,0.9);
    font-size: 1.15rem;
}

.demo-cta {
    margin-top: var(--spacing-2xl);
}

.demo-cta .btn {
    background: white;
    color: var(--gradient-mid);
    font-size: 1.1rem;
    padding: var(--spacing-lg) var(--spacing-3xl);
    box-shadow: 0 8px 30px rgba(0,0,0,0.3);
}

.demo-cta .btn:hover {
    transform: translateY(-4px) scale(1.02);
    box-shadow: 0 12px 40px rgba(0,0,0,0.4);
    color: var(--gradient-mid);
}

.demo-note {
    margin-top: var(--spacing-lg);
    font-size: 0.9rem;
    color: rgba(255,255,255,0.7);
}

/* ========================================
   Leaderboard Section
   ======================================== */
.leaderboard {
    background: var(--color-bg-alt);
}

.leaderboard-header {
    text-align: center;
    margin-bottom: var(--spacing-2xl);
}

.leaderboard-header h2 {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.leaderboard-header h2::before {
    content: '';
    display: inline-block;
    width: 24px;
    height: 24px;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    border-radius: var(--radius-sm);
}

/* Filter Buttons */
.leaderboard-filters {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-2xl);
}

.filter-group {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs);
    background: var(--glass-bg);
    border-radius: var(--radius-full);
    border: 1px solid var(--glass-border);
}

.org-filter,
.mode-filter {
    padding: var(--spacing-sm) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-full);
    background: transparent;
    color: var(--color-text-muted);
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
}

.org-filter:hover,
.mode-filter:hover {
    color: var(--color-text);
    background: rgba(255,255,255,0.05);
}

.org-filter.active,
.mode-filter.active {
    background: var(--gradient-start);
    color: white;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
}

/* Table Header */
.leaderboard-table-header {
    display: grid;
    grid-template-columns: 80px 1fr 200px 300px 50px;
    gap: var(--spacing-md);
    padding: var(--spacing-md) var(--spacing-xl);
    background: var(--glass-bg);
    border-radius: var(--radius-lg) var(--radius-lg) 0 0;
    border: 1px solid var(--glass-border);
    border-bottom: none;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.leaderboard-list {
    background: white;
    border-radius: 0 0 var(--radius-lg) var(--radius-lg);
    overflow: hidden;
    box-shadow: 0 10px 40px rgba(0,0,0,0.2);
}

/* Leaderboard Row */
.leaderboard-row {
    display: grid;
    grid-template-columns: 80px 1fr 200px 300px 50px;
    gap: var(--spacing-md);
    padding: var(--spacing-lg) var(--spacing-xl);
    align-items: center;
    background: white;
    border-bottom: 1px solid #f0f0f0;
    transition: all 0.3s ease;
    cursor: pointer;
}

.leaderboard-row:hover {
    background: #f8fafc;
}

.leaderboard-row:last-child {
    border-bottom: none;
}

/* Rank */
.row-rank {
    font-size: 1.1rem;
    font-weight: 700;
    color: #64748b;
}

.row-rank.top-3 {
    color: var(--gradient-start);
}

/* Model Info */
.row-model {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.model-logo {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    object-fit: contain;
    background: #f1f5f9;
    padding: 4px;
}

.model-name {
    font-weight: 600;
    color: #1e293b;
    font-size: 0.95rem;
}

.model-badge {
    display: inline-block;
    padding: 2px 8px;
    font-size: 0.7rem;
    font-weight: 500;
    border-radius: var(--radius-full);
    margin-left: var(--spacing-xs);
}

.badge-reasoning {
    background: rgba(139, 92, 246, 0.1);
    color: #8b5cf6;
}

.badge-standard {
    background: rgba(100, 116, 139, 0.1);
    color: #64748b;
}

/* Organization */
.row-org {
    color: #64748b;
    font-size: 0.9rem;
}

/* Score with Progress Bar */
.row-score {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.score-value {
    font-size: 0.95rem;
    font-weight: 700;
    color: #1e293b;
}

.score-value .std {
    font-weight: 400;
    font-size: 0.8rem;
    color: #94a3b8;
}

.score-bar-container {
    width: 100%;
    height: 8px;
    background: #e2e8f0;
    border-radius: var(--radius-full);
    overflow: hidden;
    position: relative;
}

.score-bar {
    height: 100%;
    border-radius: var(--radius-full);
    transition: width 1s ease-out;
    position: relative;
}

.score-bar::after {
    content: '';
    position: absolute;
    right: 0;
    top: 0;
    bottom: 0;
    width: 4px;
    background: rgba(255,255,255,0.5);
    border-radius: var(--radius-full);
}

/* Organization-specific bar colors */
.score-bar.bar-human {
    background: linear-gradient(90deg, #34d399, #10b981);
}

.score-bar.bar-openai {
    background: linear-gradient(90deg, #74aa9c, #10a37f);
}

.score-bar.bar-anthropic {
    background: linear-gradient(90deg, #d4a574, #cc785c);
}

.score-bar.bar-google {
    background: linear-gradient(90deg, #8ab4f8, #4285f4);
}

.score-bar.bar-bytedance {
    background: linear-gradient(90deg, #6ee7b7, #14b8a6);
}

.score-bar.bar-alibaba {
    background: linear-gradient(90deg, #c084fc, #a855f7);
}

/* Expand Button */
.row-expand {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: none;
    background: #f1f5f9;
    border-radius: 50%;
    color: #64748b;
    cursor: pointer;
    transition: all 0.3s ease;
}

.row-expand:hover {
    background: #e2e8f0;
    color: #1e293b;
}

.row-expand svg {
    transition: transform 0.3s ease;
}

.leaderboard-row.expanded .row-expand svg {
    transform: rotate(180deg);
}

/* Expanded Details */
.row-details {
    display: none;
    grid-column: 1 / -1;
    padding: var(--spacing-lg);
    background: #f8fafc;
    border-top: 1px solid #e2e8f0;
    margin-top: var(--spacing-md);
}

.leaderboard-row.expanded + .row-details,
.row-details.show {
    display: block;
}

.details-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: var(--spacing-md);
}

.detail-item {
    display: flex;
    justify-content: space-between;
    padding: var(--spacing-sm);
    background: white;
    border-radius: var(--radius-md);
    font-size: 0.85rem;
}

.detail-label {
    color: #64748b;
}

.detail-value {
    font-weight: 600;
    color: #1e293b;
}

/* Human Row Special Styling */
.leaderboard-row.human-row {
    background: linear-gradient(90deg, rgba(16, 185, 129, 0.05), transparent);
    border-left: 4px solid #10b981;
}

.leaderboard-row.human-row .row-rank {
    color: #10b981;
}

/* Responsive */
@media (max-width: 900px) {
    .leaderboard-table-header,
    .leaderboard-row {
        grid-template-columns: 50px 1fr 120px 40px;
    }

    .col-org,
    .row-org {
        display: none;
    }

    .leaderboard-filters {
        flex-direction: column;
        align-items: center;
    }
}

/* ========================================
   Citation Section
   ======================================== */
.citation {
    background: var(--color-bg);
}

.citation-box {
    position: relative;
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.1), rgba(118, 75, 162, 0.1));
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    max-width: 850px;
    margin: 0 auto;
    overflow: hidden;
}

.citation-box::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--color-bg-card);
    z-index: -1;
}

.citation-box pre {
    margin: 0;
    overflow-x: auto;
}

.citation-box code {
    font-family: 'JetBrains Mono', 'Monaco', 'Menlo', monospace;
    font-size: 0.9rem;
    color: var(--accent-cyan);
    white-space: pre-wrap;
    line-height: 1.6;
}

.copy-btn {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-full);
    color: var(--color-text-light);
    font-size: 0.8rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
}

.copy-btn:hover {
    background: var(--glass-bg-hover);
    border-color: var(--gradient-start);
    color: var(--color-text);
}

.copy-btn.copied {
    background: var(--color-human);
    border-color: var(--color-human);
    color: white;
}

/* ========================================
   Footer
   ======================================== */
.footer {
    position: relative;
    padding: var(--spacing-3xl) 0;
    text-align: center;
    overflow: hidden;
}

.footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, var(--color-bg-alt) 0%, var(--color-bg) 100%);
    z-index: -1;
}

.footer::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--gradient-start), var(--gradient-end), transparent);
}

.footer p {
    margin-bottom: var(--spacing-sm);
    font-size: 0.95rem;
    color: var(--color-text-light);
}

.footer-note {
    color: var(--color-text-muted);
    font-size: 0.85rem;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: var(--spacing-lg);
    margin-top: var(--spacing-lg);
}

.footer-links a {
    color: var(--color-text-muted);
    transition: all 0.3s ease;
}

.footer-links a:hover {
    color: var(--accent-cyan);
}

/* ========================================
   Responsive Design
   ======================================== */
@media (max-width: 768px) {
    .hero .title {
        font-size: 2.5rem;
    }

    .hero .subtitle {
        font-size: 1.1rem;
    }

    .hero-stats {
        flex-direction: column;
        gap: var(--spacing-lg);
    }

    .stat-card {
        width: 100%;
        max-width: 280px;
    }

    .stat-vs {
        transform: rotate(90deg);
    }

    .bar-chart {
        flex-wrap: wrap;
        height: auto;
        min-height: 300px;
        gap: var(--spacing-md);
        padding: var(--spacing-lg);
    }

    .bar {
        width: 50px;
    }

    .bar-label {
        font-size: 0.65rem;
        width: 60px;
    }

    h1 { font-size: 2rem; }
    h2 { font-size: 1.75rem; }

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

    .gallery-filters {
        gap: var(--spacing-xs);
    }

    .filter-btn {
        font-size: 0.8rem;
        padding: var(--spacing-xs) var(--spacing-md);
    }

    .nav-links {
        display: none;
    }

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

    .cost-insight {
        grid-template-columns: 1fr;
    }

    .hero-orb {
        opacity: 0.3;
    }

    .hero-orb-1 {
        width: 200px;
        height: 200px;
    }

    .hero-orb-2 {
        width: 150px;
        height: 150px;
    }

    .hero-orb-3 {
        width: 100px;
        height: 100px;
    }
}

/* ========================================
   Card Entrance Animations
   ======================================== */
.captcha-card,
.category-card,
.insight-card {
    opacity: 0;
    transform: translateY(30px);
}

.captcha-card.visible,
.category-card.visible,
.insight-card.visible {
    animation: slideUp 0.6s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

/* Stagger delays for cards */
.captcha-card:nth-child(1), .category-card:nth-child(1) { animation-delay: 0.05s; }
.captcha-card:nth-child(2), .category-card:nth-child(2) { animation-delay: 0.1s; }
.captcha-card:nth-child(3), .category-card:nth-child(3) { animation-delay: 0.15s; }
.captcha-card:nth-child(4), .category-card:nth-child(4) { animation-delay: 0.2s; }
.captcha-card:nth-child(5), .category-card:nth-child(5) { animation-delay: 0.25s; }
.captcha-card:nth-child(6) { animation-delay: 0.3s; }
.captcha-card:nth-child(7) { animation-delay: 0.35s; }
.captcha-card:nth-child(8) { animation-delay: 0.4s; }
.captcha-card:nth-child(9) { animation-delay: 0.45s; }

/* Loading shimmer for images */
.captcha-preview.loading {
    background: linear-gradient(
        90deg,
        var(--color-bg-card) 0%,
        var(--glass-bg-hover) 50%,
        var(--color-bg-card) 100%
    );
    background-size: 200% 100%;
    animation: shimmer 1.5s infinite;
}