/* ==========================================
   SuperBirder - Official Website
   Based on SuperPicky Design System
   Color: #C8FF00 (Yellow-Green)
   ========================================== */

/* === CSS Variables === */
:root {
    /* Backgrounds - dark theme */
    --bg-void: #0a0a0a;
    --bg-primary: #111111;
    --bg-elevated: #1a1a1a;
    --bg-card: #1f1f1f;
    --bg-input: #262626;

    /* Text hierarchy */
    --text-primary: #fafafa;
    --text-secondary: #a1a1a1;
    --text-tertiary: #666666;
    --text-muted: #404040;

    /* Accent - SuperBirder Yellow-Green */
    --accent: #C8FF00;
    --accent-dim: rgba(200, 255, 0, 0.15);
    --accent-glow: rgba(200, 255, 0, 0.25);
    --accent-hover: #D4FF33;

    /* Status colors */
    --star-gold: #E6B34D;
    --success: #22c55e;
    --crown-gold: #FFD700;

    /* Borders */
    --border: #2a2a2a;
    --border-subtle: #1e1e1e;

    /* Spacing */
    --space-xs: 4px;
    --space-sm: 8px;
    --space-md: 16px;
    --space-lg: 24px;
    --space-xl: 48px;
    --space-2xl: 80px;

    /* Border radius */
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --radius-xl: 24px;

    /* Fonts */
    --font-sans: "PingFang SC", "Microsoft YaHei", "Noto Sans CJK SC", -apple-system, sans-serif;
    --font-mono: "Space Mono", "Menlo", "Monaco", monospace;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* === Grain Texture Overlay === */
.grain {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 9999;
    opacity: 0.03;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%' height='100%' filter='url(%23noise)'/%3E%3C/svg%3E");
}

/* === Container === */
.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

/* === Header === */
header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(17, 17, 17, 0.85);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-subtle);
}

.header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-md) var(--space-lg);
    max-width: 1000px;
    margin: 0 auto;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    text-decoration: none;
    color: var(--text-primary);
    transition: opacity 0.2s;
}

.logo:hover {
    opacity: 0.8;
}

.logo img {
    width: 32px;
    height: 32px;
    border-radius: 8px;
}

.logo span {
    font-size: 15px;
    font-weight: 600;
    letter-spacing: -0.3px;
}

.lang-switch {
    display: flex;
    gap: 2px;
    background: var(--bg-elevated);
    border-radius: var(--radius-sm);
    padding: 2px;
}

.lang-btn {
    padding: 6px 12px;
    background: transparent;
    border: none;
    color: var(--text-tertiary);
    font-size: 12px;
    font-weight: 500;
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.2s;
}

.lang-btn.active {
    background: var(--accent);
    color: var(--bg-void);
}

.lang-btn:hover:not(.active) {
    color: var(--text-secondary);
}

/* === Language Toggle === */
[data-lang="cn"] .lang-en {
    display: none !important;
}

[data-lang="en"] .lang-cn {
    display: none !important;
}

/* === Hero Section === */
.hero {
    padding: 140px 0 var(--space-xl);
    text-align: center;
}

.hero-badge {
    display: inline-block;
    padding: 6px 14px;
    background: var(--accent-dim);
    border: 1px solid rgba(200, 255, 0, 0.2);
    border-radius: 20px;
    font-size: 12px;
    color: var(--accent);
    margin-bottom: var(--space-lg);
    letter-spacing: 0.5px;
}

/* App Icon + Title */
.hero-brand {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-md);
    margin-bottom: var(--space-md);
}

.hero-icon {
    width: 80px;
    height: 80px;
    border-radius: var(--radius-lg);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
}

.hero h1 {
    font-size: clamp(40px, 8vw, 64px);
    font-weight: 700;
    letter-spacing: -2px;
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--text-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.tagline {
    font-size: 18px;
    color: var(--text-secondary);
    margin-bottom: var(--space-xl);
    font-weight: 400;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: var(--space-xl);
    margin-bottom: var(--space-xl);
}

.stat-item {
    text-align: center;
}

.stat-number {
    font-size: 28px;
    font-weight: 700;
    color: var(--accent);
    font-family: var(--font-mono);
}

.stat-label {
    font-size: 12px;
    color: var(--text-tertiary);
    margin-top: 4px;
}

.hero-cta {
    display: flex;
    gap: var(--space-md);
    justify-content: center;
    flex-wrap: wrap;
}

/* === Buttons === */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    padding: 14px 28px;
    border-radius: var(--radius-sm);
    font-size: 14px;
    font-weight: 500;
    text-decoration: none;
    transition: all 0.2s ease;
    border: none;
    cursor: pointer;
}

.btn-primary {
    background: var(--accent);
    color: var(--bg-void);
}

.btn-primary:hover {
    background: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 8px 24px var(--accent-glow);
}

.btn-appstore {
    background: #000;
    color: #fff;
    border: 1px solid #333;
    padding: 10px 24px;
}

.btn-appstore:hover {
    background: #1a1a1a;
    border-color: #444;
}

.btn-appstore img {
    height: 24px;
}

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

.btn-ghost:hover {
    color: var(--text-primary);
    border-color: var(--text-tertiary);
}

/* === Hero Preview (Phone Mockup) === */
.hero-preview {
    margin-top: var(--space-xl);
    padding-bottom: var(--space-lg);
}

.phone-mockup {
    position: relative;
    max-width: 280px;
    margin: 0 auto;
}

.phone-frame {
    position: relative;
    border-radius: 40px;
    overflow: hidden;
    border: 8px solid #2a2a2a;
    background: var(--bg-card);
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5);
}

.phone-screen {
    width: 100%;
    aspect-ratio: 1206 / 2622; /* iPhone 16 Pro ratio */
    object-fit: cover;
    display: block;
}

.phone-placeholder {
    width: 100%;
    aspect-ratio: 1206 / 2622; /* iPhone 16 Pro ratio */
    background: linear-gradient(135deg, var(--bg-elevated) 0%, var(--bg-card) 100%);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    color: var(--text-tertiary);
    font-size: 14px;
    gap: var(--space-sm);
}

.phone-placeholder-icon {
    font-size: 48px;
    opacity: 0.5;
}

.phone-placeholder-text {
    text-align: center;
    line-height: 1.4;
}

.phone-placeholder-size {
    font-size: 11px;
    font-family: var(--font-mono);
    color: var(--text-muted);
}

.phone-glow {
    position: absolute;
    inset: -50px;
    background: radial-gradient(ellipse at center, var(--accent-glow) 0%, transparent 70%);
    pointer-events: none;
    z-index: -1;
}

/* === Features Section === */
.features {
    padding: var(--space-2xl) 0;
}

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

@media (max-width: 900px) {
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 600px) {
    .features-grid {
        grid-template-columns: 1fr;
    }
}

.feature-card {
    background: var(--bg-elevated);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    padding: var(--space-lg);
    transition: all 0.3s ease;
    position: relative;
}

.feature-card:hover {
    border-color: var(--border);
    transform: translateY(-2px);
}

.feature-number {
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--accent);
    margin-bottom: var(--space-md);
    opacity: 0.7;
}

.feature-icon {
    font-size: 28px;
    margin-bottom: var(--space-sm);
}

.feature-card h3 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: var(--space-sm);
    color: var(--text-primary);
}

.feature-card p {
    font-size: 13px;
    color: var(--text-secondary);
    line-height: 1.5;
}

/* === Section Header === */
.section-header {
    margin-bottom: var(--space-xl);
}

.section-label {
    display: inline-block;
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 2px;
    color: var(--text-tertiary);
    padding: 8px 16px;
    background: var(--bg-elevated);
    border-radius: var(--radius-sm);
}

/* === Version Section === */
.version-section {
    padding: var(--space-2xl) 0;
    background: var(--bg-void);
}

.version-card {
    background: var(--bg-elevated);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    padding: var(--space-lg);
}

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

.version-badge {
    padding: 6px 12px;
    background: var(--accent);
    color: var(--bg-void);
    border-radius: var(--radius-sm);
    font-size: 14px;
    font-weight: 600;
    font-family: var(--font-mono);
}

.version-date {
    font-size: 13px;
    color: var(--text-tertiary);
}

.version-list {
    list-style: none;
}

.version-list li {
    padding: 8px 0;
    border-bottom: 1px solid var(--border-subtle);
    font-size: 14px;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.version-list li:last-child {
    border-bottom: none;
}

.version-list li::before {
    content: "✓";
    color: var(--accent);
    font-weight: bold;
}

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

.download-card {
    background: var(--bg-elevated);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
    padding: var(--space-xl);
    text-align: center;
}

.download-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto var(--space-md);
    border-radius: var(--radius-lg);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

.download-title {
    font-size: 24px;
    font-weight: 600;
    margin-bottom: var(--space-sm);
}

.download-subtitle {
    font-size: 14px;
    color: var(--text-tertiary);
    margin-bottom: var(--space-lg);
}

.download-badges {
    display: flex;
    justify-content: center;
    gap: var(--space-md);
    flex-wrap: wrap;
}

.app-store-badge {
    height: 50px;
    transition: transform 0.2s;
}

.app-store-badge:hover {
    transform: scale(1.05);
}

.download-requirements {
    margin-top: var(--space-lg);
    font-size: 12px;
    color: var(--text-muted);
}

/* === Help Section (FAQ/Tutorial Link) === */
.help-section {
    padding: var(--space-xl) 0;
}

.help-card {
    display: flex;
    align-items: center;
    gap: var(--space-lg);
    background: var(--bg-elevated);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    padding: var(--space-lg);
}

.help-icon {
    font-size: 32px;
}

.help-content {
    flex: 1;
}

.help-content h3 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 4px;
}

.help-content p {
    font-size: 13px;
    color: var(--text-tertiary);
}

.help-buttons {
    display: flex;
    gap: var(--space-sm);
}

.btn-coming-soon {
    opacity: 0.5;
    cursor: not-allowed;
}

/* === Tools Section === */
.tools-section {
    padding: var(--space-2xl) 0;
    background: var(--bg-void);
}

.tools-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-md);
}

@media (max-width: 800px) {
    .tools-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

.tool-item {
    display: flex;
    flex-direction: column;
    padding: var(--space-md);
    background: var(--bg-elevated);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    text-decoration: none;
    transition: all 0.2s;
}

.tool-item:hover {
    border-color: var(--border);
    transform: translateY(-2px);
}

.tool-name {
    font-size: 14px;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.tool-desc {
    font-size: 12px;
    color: var(--text-tertiary);
}

/* === Footer === */
footer {
    padding: var(--space-xl) 0;
    border-top: 1px solid var(--border-subtle);
}

.footer-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--space-md);
}

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

.footer-brand img {
    width: 28px;
    height: 28px;
    border-radius: 6px;
}

.footer-brand-text {
    display: flex;
    flex-direction: column;
}

.footer-brand-text span:first-child {
    font-weight: 600;
    font-size: 14px;
}

.footer-author {
    font-size: 11px;
    color: var(--text-tertiary);
}

.footer-links {
    display: flex;
    gap: var(--space-lg);
}

.footer-links a {
    color: var(--text-tertiary);
    text-decoration: none;
    font-size: 13px;
    transition: color 0.2s;
}

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

.footer-bottom {
    margin-top: var(--space-lg);
    padding-top: var(--space-lg);
    border-top: 1px solid var(--border-subtle);
    text-align: center;
}

.copyright {
    font-size: 12px;
    color: var(--text-muted);
}

/* === Responsive === */
@media (max-width: 768px) {
    .hero-brand {
        flex-direction: column;
    }
    
    .hero-stats {
        flex-direction: column;
        gap: var(--space-md);
    }
    
    .help-card {
        flex-direction: column;
        text-align: center;
    }
    
    .help-buttons {
        justify-content: center;
    }
    
    .footer-inner {
        flex-direction: column;
        text-align: center;
    }
    
    .footer-links {
        justify-content: center;
    }
}