/* CSS Variables */
:root {
    --bg-deep: #0a0e14;
    --bg-primary: #1a1a2e;
    --bg-secondary: #121820;
    --bg-panel: rgba(18, 24, 32, 0.95);
    --accent-cyan: #00d4ff;
    --accent-purple: #8b5cf6;
    --accent-pink: #ec4899;
    --accent-green: #10b981;
    --accent-red: #ef4444;
    --accent-orange: #f97316;
    --text-primary: #e6edf3;
    --text-secondary: #8b949e;
    --border-subtle: rgba(255, 255, 255, 0.08);
    --border-glow: rgba(0, 212, 255, 0.3);
    --shadow-glow: 0 0 40px rgba(0, 212, 255, 0.15);
    --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

/* Base Styles */
html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: var(--bg-deep);
    color: var(--text-primary);
    min-height: 100vh;
    overflow-x: hidden;
    line-height: 1.6;
}

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

/* Header */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 32px;
    background: linear-gradient(180deg, rgba(10, 14, 20, 0.98) 0%, rgba(10, 14, 20, 0) 100%);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-subtle);
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 1.25rem;
    font-weight: 700;
    letter-spacing: 3px;
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-purple));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.logo svg {
    filter: drop-shadow(0 0 10px rgba(0, 212, 255, 0.5));
}

.nav {
    display: flex;
    gap: 32px;
}

.nav a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 500;
    transition: var(--transition-smooth);
    position: relative;
}

.nav a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--accent-cyan), var(--accent-purple));
    transition: var(--transition-smooth);
}

.nav a:hover {
    color: var(--text-primary);
}

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

.btn-upload {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 20px;
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-purple));
    border: none;
    border-radius: 10px;
    color: white;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-smooth);
    box-shadow: 0 4px 20px rgba(0, 212, 255, 0.3);
}

.btn-upload:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(0, 212, 255, 0.4);
}

/* 3D Brain Container */
#brain-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
}

#brain-container canvas {
    display: block;
}

/* Info Panel */
.info-panel {
    position: fixed;
    top: 50%;
    right: 32px;
    transform: translateY(-50%);
    z-index: 50;
    width: 360px;
    max-height: calc(100vh - 120px);
    overflow-y: auto;
    background: var(--bg-panel);
    border: 1px solid var(--border-subtle);
    border-radius: 20px;
    padding: 28px;
    box-shadow: var(--shadow-glow), 0 25px 50px rgba(0, 0, 0, 0.4);
    backdrop-filter: blur(20px);
}

.info-panel::-webkit-scrollbar {
    width: 6px;
}

.info-panel::-webkit-scrollbar-track {
    background: transparent;
}

.info-panel::-webkit-scrollbar-thumb {
    background: var(--accent-cyan);
    border-radius: 3px;
}

.close-btn {
    position: absolute;
    top: 16px;
    right: 16px;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-subtle);
    border-radius: 8px;
    color: var(--text-secondary);
    font-size: 1.25rem;
    cursor: pointer;
    transition: var(--transition-smooth);
}

.close-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-primary);
    border-color: var(--accent-cyan);
}

#region-name {
    font-size: 1.5rem;
    margin-bottom: 12px;
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-purple));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

#region-description {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
    margin-bottom: 20px;
}

.region-facts {
    list-style: none;
    margin-bottom: 24px;
}

.region-facts li {
    position: relative;
    padding-left: 24px;
    margin-bottom: 12px;
    font-size: 0.9rem;
    color: var(--text-primary);
}

.region-facts li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 8px;
    width: 8px;
    height: 8px;
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-purple));
    border-radius: 50%;
}

.btn-primary {
    width: 100%;
    padding: 14px 24px;
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-purple));
    border: none;
    border-radius: 12px;
    color: white;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-smooth);
    box-shadow: 0 4px 20px rgba(0, 212, 255, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(0, 212, 255, 0.4);
}

.external-tools {
    margin-top: 24px;
    padding-top: 24px;
    border-top: 1px solid var(--border-subtle);
}

.external-tools h3 {
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 1.5px;
    color: var(--text-secondary);
    margin-bottom: 16px;
}

#tool-links {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

#tool-links a {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 12px 16px;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--border-subtle);
    border-radius: 10px;
    color: var(--text-primary);
    text-decoration: none;
    font-size: 0.9rem;
    transition: var(--transition-smooth);
}

#tool-links a:hover {
    background: rgba(255, 255, 255, 0.06);
    border-color: var(--accent-cyan);
    transform: translateX(4px);
}

#tool-links a::before {
    content: '↗';
    font-size: 1rem;
    color: var(--accent-cyan);
}

/* Controls */
.controls {
    position: fixed;
    bottom: 100px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 50;
    display: flex;
    gap: 16px;
    padding: 12px;
    background: var(--bg-panel);
    border: 1px solid var(--border-subtle);
    border-radius: 16px;
    backdrop-filter: blur(20px);
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
}

.btn-nav {
    padding: 12px 24px;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-subtle);
    border-radius: 10px;
    color: var(--text-primary);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition-smooth);
}

.btn-nav:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: var(--accent-cyan);
}

.btn-study {
    padding: 12px 32px;
    background: linear-gradient(135deg, var(--accent-purple), var(--accent-pink));
    border: none;
    border-radius: 10px;
    color: white;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-smooth);
    box-shadow: 0 4px 20px rgba(139, 92, 246, 0.3);
}

.btn-study:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(139, 92, 246, 0.4);
}

/* Reset Container */
.reset-container {
    position: fixed;
    bottom: 32px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 50;
}

.btn-reset {
    padding: 10px 24px;
    background: transparent;
    border: 1px solid var(--border-subtle);
    border-radius: 10px;
    color: var(--text-secondary);
    font-size: 0.85rem;
    cursor: pointer;
    transition: var(--transition-smooth);
}

.btn-reset:hover {
    background: rgba(255, 255, 255, 0.05);
    border-color: var(--accent-cyan);
    color: var(--text-primary);
}

/* Study Mode Overlay */
.study-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 200;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(10, 14, 20, 0.9);
    backdrop-filter: blur(10px);
}

.study-card {
    position: relative;
    width: 90%;
    max-width: 560px;
    background: var(--bg-panel);
    border: 1px solid var(--border-subtle);
    border-radius: 24px;
    padding: 40px;
    box-shadow: var(--shadow-glow), 0 25px 50px rgba(0, 0, 0, 0.5);
}

.study-question {
    font-size: 1.4rem;
    font-weight: 600;
    text-align: center;
    margin-bottom: 32px;
    line-height: 1.5;
    color: var(--text-primary);
}

.study-options {
    display: grid;
    gap: 12px;
}

.study-option {
    padding: 16px 24px;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--border-subtle);
    border-radius: 12px;
    color: var(--text-primary);
    font-size: 1rem;
    text-align: left;
    cursor: pointer;
    transition: var(--transition-smooth);
}

.study-option:hover {
    background: rgba(255, 255, 255, 0.06);
    border-color: var(--accent-cyan);
    transform: translateX(4px);
}

.study-option.correct {
    background: rgba(16, 185, 129, 0.15);
    border-color: var(--accent-green);
}

.study-option.incorrect {
    background: rgba(239, 68, 68, 0.15);
    border-color: var(--accent-red);
}

.study-feedback {
    margin-top: 24px;
    padding: 20px;
    border-radius: 12px;
    text-align: center;
    font-size: 1rem;
    font-weight: 500;
}

.study-feedback.correct {
    background: rgba(16, 185, 129, 0.1);
    border: 1px solid var(--accent-green);
    color: var(--accent-green);
}

.study-feedback.incorrect {
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid #ef4444;
    color: #ef4444;
}

.study-progress {
    margin-top: 24px;
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Upload Overlay */
.upload-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 200;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(10, 14, 20, 0.9);
    backdrop-filter: blur(10px);
}

.upload-card {
    position: relative;
    width: 90%;
    max-width: 500px;
    background: var(--bg-panel);
    border: 1px solid var(--border-subtle);
    border-radius: 24px;
    padding: 48px 40px;
    text-align: center;
    box-shadow: var(--shadow-glow), 0 25px 50px rgba(0, 0, 0, 0.5);
}

.upload-card h2 {
    font-size: 1.5rem;
    margin-bottom: 12px;
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-purple));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.upload-card > p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin-bottom: 32px;
}

.drop-zone {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 16px;
    padding: 48px 32px;
    border: 2px dashed var(--border-subtle);
    border-radius: 16px;
    cursor: pointer;
    transition: var(--transition-smooth);
}

.drop-zone:hover {
    border-color: var(--accent-cyan);
    background: rgba(0, 212, 255, 0.03);
}

.drop-zone svg {
    color: var(--text-secondary);
}

.drop-zone p {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.upload-progress {
    margin-top: 24px;
}

.upload-progress-bar {
    width: 100%;
    height: 6px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 3px;
    overflow: hidden;
}

.upload-progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--accent-cyan), var(--accent-purple));
    border-radius: 3px;
    transition: width 0.3s ease;
}

.upload-progress-text {
    margin-top: 12px;
    color: var(--text-secondary);
    font-size: 0.85rem;
}

/* Hidden Utility Class */
.hidden {
    display: none !important;
}

/* Responsive */
@media (max-width: 768px) {
    .header {
        padding: 12px 16px;
    }

    .logo span {
        display: none;
    }

    .nav {
        gap: 16px;
    }

    .nav a {
        font-size: 0.85rem;
    }

    .btn-upload span {
        display: none;
    }

    .btn-upload {
        padding: 10px;
        border-radius: 10px;
    }

    .info-panel {
        top: auto;
        bottom: 0;
        right: 0;
        left: 0;
        width: 100%;
        max-height: 50vh;
        border-radius: 24px 24px 0 0;
        transform: none;
    }

    .controls {
        bottom: auto;
        top: 50%;
        transform: translate(-50%, -50%);
        gap: 8px;
        padding: 8px;
    }

    .btn-nav {
        padding: 10px 16px;
        font-size: 0.8rem;
    }

    .btn-study {
        padding: 10px 20px;
        font-size: 0.8rem;
    }

    .reset-container {
        bottom: auto;
        top: calc(50% + 60px);
    }

    .study-card,
    .upload-card {
        padding: 32px 24px;
    }

    .study-question {
        font-size: 1.2rem;
    }
}

@media (max-width: 480px) {
    .nav {
        display: none;
    }

    .controls {
        flex-wrap: wrap;
        justify-content: center;
        max-width: 280px;
    }
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

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

.animate-fadeIn {
    animation: fadeIn 0.5s ease forwards;
}

.animate-pulse {
    animation: pulse 2s ease-in-out infinite;
}

/* Loading State */
.loading {
    position: relative;
    pointer-events: none;
}

.loading::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.1), transparent);
    background-size: 200% 100%;
    animation: shimmer 1.5s infinite;
}