/* MChat Official Website - Global Styles */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

:root {
    --primary: #00D4AA;
    --primary-dark: #00B894;
    --bg-dark: #0A0A0F;
    --bg-card: #111118;
    --bg-section: #0E0E16;
    --bg-footer: #08080D;
    --text-primary: #FFFFFF;
    --text-secondary: #B0B0C0;
    --text-muted: #70708A;
    --accent: #FF6B35;
    --border: #1E1E2E;
    --gradient-1: linear-gradient(135deg, #00D4AA 0%, #2B7FFF 100%);
    --gradient-2: linear-gradient(135deg, #1A1A2E 0%, #0A0A0F 100%);
    --shadow: 0 4px 24px rgba(0, 212, 170, 0.08);
    --radius: 12px;
    --radius-lg: 20px;
}

html { scroll-behavior: smooth; font-size: 16px; }

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-primary);
    line-height: 1.7;
    overflow-x: hidden;
}

a { color: var(--primary); text-decoration: none; transition: color 0.3s; }
a:hover { color: var(--primary-dark); }

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

/* ===== NAVIGATION ===== */
.navbar {
    position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
    background: rgba(10, 10, 15, 0.85);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    padding: 0 24px;
}
.navbar .container {
    display: flex; align-items: center; justify-content: space-between;
    height: 72px;
}
.nav-brand { display: flex; align-items: center; gap: 10px; }
.nav-brand .logo-icon {
    width: 36px; height: 36px; background: var(--gradient-1);
    border-radius: 10px; display: flex; align-items: center; justify-content: center;
    font-weight: 700; font-size: 18px; color: #fff;
}
.nav-brand span { font-size: 22px; font-weight: 700; color: var(--text-primary); }
.nav-links { display: flex; align-items: center; gap: 32px; list-style: none; }
.nav-links a {
    color: var(--text-secondary); font-size: 15px; font-weight: 500;
    transition: color 0.3s; padding: 8px 0;
}
.nav-links a:hover, .nav-links a.active { color: var(--primary); }
.nav-cta a {
    display: inline-block; padding: 10px 24px; background: var(--primary);
    color: #0A0A0F !important; font-weight: 600; border-radius: 8px;
    font-size: 14px; transition: all 0.3s;
}
.nav-cta a:hover { background: var(--primary-dark); transform: translateY(-1px); box-shadow: 0 4px 16px rgba(0,212,170,0.3); }

.mobile-toggle { display: none; background: none; border: none; cursor: pointer; padding: 8px; }
.mobile-toggle span { display: block; width: 24px; height: 2px; background: var(--text-primary); margin: 5px 0; transition: 0.3s; }

/* ===== HERO ===== */
.hero {
    min-height: 100vh; display: flex; align-items: center; justify-content: center;
    text-align: center; padding: 120px 24px 80px;
    background: radial-gradient(ellipse at 50% 0%, rgba(0,212,170,0.08) 0%, transparent 60%),
                radial-gradient(ellipse at 80% 50%, rgba(43,127,255,0.05) 0%, transparent 50%),
                var(--bg-dark);
    position: relative; overflow: hidden;
}
.hero::before {
    content: ''; position: absolute; top: -50%; left: -50%; width: 200%; height: 200%;
    background: radial-gradient(circle at 30% 40%, rgba(0,212,170,0.03) 0%, transparent 50%),
                radial-gradient(circle at 70% 60%, rgba(43,127,255,0.03) 0%, transparent 50%);
    animation: heroGlow 15s ease-in-out infinite alternate;
}
@keyframes heroGlow { 0% { transform: translate(0, 0); } 100% { transform: translate(-5%, -3%); } }

.hero-content { position: relative; z-index: 1; max-width: 800px; }
.hero-badge {
    display: inline-block; padding: 6px 16px; background: rgba(0,212,170,0.1);
    border: 1px solid rgba(0,212,170,0.2); border-radius: 20px;
    font-size: 13px; color: var(--primary); margin-bottom: 24px;
}
.hero h1 {
    font-size: clamp(36px, 6vw, 64px); font-weight: 800; line-height: 1.15;
    margin-bottom: 24px;
    background: linear-gradient(135deg, #FFFFFF 0%, #B0B0C0 100%);
    -webkit-background-clip: text; -webkit-text-fill-color: transparent;
    background-clip: text;
}
.hero h1 .highlight {
    background: var(--gradient-1);
    -webkit-background-clip: text; -webkit-text-fill-color: transparent;
    background-clip: text;
}
.hero p { font-size: clamp(16px, 2vw, 20px); color: var(--text-secondary); margin-bottom: 40px; max-width: 600px; margin-left: auto; margin-right: auto; }
.hero-buttons { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }
.btn-primary {
    display: inline-block; padding: 14px 36px; background: var(--primary);
    color: #0A0A0F !important; font-weight: 700; border-radius: 10px;
    font-size: 16px; transition: all 0.3s;
}
.btn-primary:hover { background: var(--primary-dark); transform: translateY(-2px); box-shadow: 0 8px 24px rgba(0,212,170,0.3); }
.btn-secondary {
    display: inline-block; padding: 14px 36px;
    border: 1px solid var(--border); color: var(--text-primary) !important;
    font-weight: 600; border-radius: 10px; font-size: 16px; transition: all 0.3s;
}
.btn-secondary:hover { border-color: var(--primary); color: var(--primary) !important; }

/* ===== SECTIONS ===== */
.section { padding: 100px 24px; }
.section-alt { background: var(--bg-section); }
.section-header { text-align: center; margin-bottom: 64px; }
.section-header .tag {
    display: inline-block; padding: 4px 14px; background: rgba(0,212,170,0.1);
    border-radius: 16px; font-size: 13px; color: var(--primary); margin-bottom: 16px;
}
.section-header h2 { font-size: clamp(28px, 4vw, 42px); font-weight: 700; margin-bottom: 16px; }
.section-header p { font-size: 18px; color: var(--text-secondary); max-width: 600px; margin: 0 auto; }

/* ===== VALUE CARDS ===== */
.value-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.value-card {
    background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius-lg);
    padding: 36px 28px; text-align: center; transition: all 0.3s;
}
.value-card:hover { transform: translateY(-4px); border-color: rgba(0,212,170,0.3); box-shadow: var(--shadow); }
.value-card .icon { font-size: 40px; margin-bottom: 20px; display: block; }
.value-card h3 { font-size: 18px; font-weight: 600; margin-bottom: 12px; }
.value-card p { font-size: 14px; color: var(--text-secondary); line-height: 1.7; }

/* ===== FEATURE BLOCKS ===== */
.feature-block { display: flex; align-items: center; gap: 64px; margin-bottom: 80px; }
.feature-block:nth-child(even) { flex-direction: row-reverse; }
.feature-block:last-child { margin-bottom: 0; }
.feature-text { flex: 1; }
.feature-text .tag { display: inline-block; padding: 4px 12px; background: rgba(0,212,170,0.1); border-radius: 12px; font-size: 12px; color: var(--primary); margin-bottom: 16px; }
.feature-text h3 { font-size: 28px; font-weight: 700; margin-bottom: 16px; }
.feature-text p { font-size: 16px; color: var(--text-secondary); margin-bottom: 20px; }
.feature-text ul { list-style: none; }
.feature-text ul li { padding: 6px 0; color: var(--text-secondary); font-size: 15px; }
.feature-text ul li::before { content: "✓"; color: var(--primary); font-weight: 700; margin-right: 10px; }
.feature-visual {
    flex: 1; background: var(--bg-card); border: 1px solid var(--border);
    border-radius: var(--radius-lg); padding: 40px; min-height: 300px;
    display: flex; align-items: center; justify-content: center;
    position: relative; overflow: hidden;
}
.feature-visual::before {
    content: ''; position: absolute; inset: 0;
    background: radial-gradient(circle at 50% 50%, rgba(0,212,170,0.05) 0%, transparent 70%);
}
.feature-visual .visual-icon { font-size: 80px; position: relative; z-index: 1; }

/* ===== SECURITY SECTION ===== */
.security-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.security-card {
    background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius-lg);
    padding: 36px; transition: all 0.3s;
}
.security-card:hover { border-color: rgba(0,212,170,0.3); }
.security-card .icon { font-size: 32px; margin-bottom: 16px; display: block; }
.security-card h3 { font-size: 20px; font-weight: 600; margin-bottom: 12px; }
.security-card p { font-size: 15px; color: var(--text-secondary); line-height: 1.7; }

/* ===== STATS ===== */
.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.stat-item { text-align: center; padding: 32px 16px; }
.stat-number {
    font-size: clamp(36px, 5vw, 52px); font-weight: 800;
    background: var(--gradient-1); -webkit-background-clip: text;
    -webkit-text-fill-color: transparent; background-clip: text;
    margin-bottom: 8px;
}
.stat-label { font-size: 15px; color: var(--text-secondary); }

/* ===== DOWNLOAD SECTION ===== */
.download-section {
    background: radial-gradient(ellipse at 50% 50%, rgba(0,212,170,0.06) 0%, transparent 70%),
                var(--bg-section);
}
.download-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; margin-top: 48px; }
.download-card {
    background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius-lg);
    padding: 32px 24px; text-align: center; transition: all 0.3s;
}
.download-card:hover { border-color: var(--primary); transform: translateY(-4px); box-shadow: var(--shadow); }
.download-card .platform-icon { font-size: 40px; margin-bottom: 16px; display: block; }
.download-card h3 { font-size: 18px; font-weight: 600; margin-bottom: 8px; }
.download-card p { font-size: 13px; color: var(--text-muted); margin-bottom: 20px; }
.download-card a {
    display: inline-block; padding: 10px 28px; background: var(--primary);
    color: #0A0A0F !important; font-weight: 600; border-radius: 8px;
    font-size: 14px; transition: all 0.3s;
}
.download-card a:hover { background: var(--primary-dark); }

/* ===== FAQ ===== */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
    background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius);
    padding: 32px; margin-bottom: 20px;
}
.faq-item h3 { font-size: 18px; font-weight: 600; margin-bottom: 16px; color: var(--primary); }
.faq-item .answer p { font-size: 15px; color: var(--text-secondary); margin-bottom: 12px; }
.faq-item .steps { list-style: none; counter-reset: step; }
.faq-item .steps li {
    counter-increment: step; padding: 8px 0; font-size: 15px; color: var(--text-secondary);
    padding-left: 36px; position: relative;
}
.faq-item .steps li::before {
    content: counter(step); position: absolute; left: 0; top: 8px;
    width: 24px; height: 24px; background: rgba(0,212,170,0.1);
    border-radius: 50%; display: flex; align-items: center; justify-content: center;
    font-size: 12px; font-weight: 700; color: var(--primary);
}

/* ===== FOOTER ===== */
.footer {
    background: var(--bg-footer); border-top: 1px solid var(--border);
    padding: 64px 24px 32px;
}
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr 1fr; gap: 40px; margin-bottom: 48px; }
.footer-brand .logo { display: flex; align-items: center; gap: 10px; margin-bottom: 16px; }
.footer-brand .logo .logo-icon {
    width: 32px; height: 32px; background: var(--gradient-1);
    border-radius: 8px; display: flex; align-items: center; justify-content: center;
    font-weight: 700; font-size: 16px; color: #fff;
}
.footer-brand .logo span { font-size: 20px; font-weight: 700; }
.footer-brand p { font-size: 14px; color: var(--text-muted); line-height: 1.7; }
.footer-col h4 { font-size: 14px; font-weight: 600; margin-bottom: 16px; color: var(--text-primary); }
.footer-col ul { list-style: none; }
.footer-col ul li { margin-bottom: 10px; }
.footer-col ul li a { font-size: 14px; color: var(--text-muted); transition: color 0.3s; }
.footer-col ul li a:hover { color: var(--primary); }
.footer-bottom {
    border-top: 1px solid var(--border); padding-top: 24px;
    display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 16px;
}
.footer-bottom p { font-size: 13px; color: var(--text-muted); }
.footer-social { display: flex; gap: 16px; }
.footer-social a {
    width: 36px; height: 36px; border: 1px solid var(--border); border-radius: 8px;
    display: flex; align-items: center; justify-content: center;
    color: var(--text-muted); font-size: 14px; transition: all 0.3s;
}
.footer-social a:hover { border-color: var(--primary); color: var(--primary); }

/* ===== PAGE HERO (sub pages) ===== */
.page-hero {
    padding: 140px 24px 60px; text-align: center;
    background: radial-gradient(ellipse at 50% 0%, rgba(0,212,170,0.06) 0%, transparent 60%), var(--bg-dark);
}
.page-hero h1 { font-size: clamp(32px, 5vw, 48px); font-weight: 700; margin-bottom: 16px; }
.page-hero p { font-size: 18px; color: var(--text-secondary); max-width: 600px; margin: 0 auto; }

/* ===== FEATURES PAGE ===== */
.features-detail { padding: 80px 24px; }
.feature-detail-card {
    background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius-lg);
    padding: 48px; margin-bottom: 32px; display: flex; gap: 40px; align-items: flex-start;
}
.feature-detail-card .icon-wrap {
    width: 64px; height: 64px; min-width: 64px; background: rgba(0,212,170,0.1);
    border-radius: 16px; display: flex; align-items: center; justify-content: center;
    font-size: 28px;
}
.feature-detail-card h3 { font-size: 22px; font-weight: 600; margin-bottom: 12px; }
.feature-detail-card p { font-size: 15px; color: var(--text-secondary); line-height: 1.8; }

/* ===== SECURITY PAGE ===== */
.security-detail { padding: 80px 24px; }
.security-detail-card {
    background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius-lg);
    padding: 48px; margin-bottom: 32px;
}
.security-detail-card h3 { font-size: 22px; font-weight: 600; margin-bottom: 16px; display: flex; align-items: center; gap: 12px; }
.security-detail-card p { font-size: 15px; color: var(--text-secondary); line-height: 1.8; }

/* ===== HELP PAGE ===== */
.help-content { padding: 80px 24px; }
.help-categories { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; margin-bottom: 64px; }
.help-cat-card {
    background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius-lg);
    padding: 32px; text-align: center; transition: all 0.3s;
}
.help-cat-card:hover { border-color: rgba(0,212,170,0.3); }
.help-cat-card .icon { font-size: 36px; margin-bottom: 16px; display: block; }
.help-cat-card h3 { font-size: 18px; font-weight: 600; margin-bottom: 8px; }
.help-cat-card p { font-size: 14px; color: var(--text-secondary); }

/* ===== ABOUT PAGE ===== */
.about-content { padding: 80px 24px; }
.about-story { max-width: 800px; margin: 0 auto 64px; }
.about-story p { font-size: 16px; color: var(--text-secondary); line-height: 1.9; margin-bottom: 20px; }
.team-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.team-card {
    background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius-lg);
    padding: 32px; text-align: center;
}
.team-card .avatar {
    width: 80px; height: 80px; background: var(--gradient-1); border-radius: 50%;
    margin: 0 auto 16px; display: flex; align-items: center; justify-content: center;
    font-size: 32px;
}
.team-card h3 { font-size: 18px; font-weight: 600; margin-bottom: 4px; }
.team-card p { font-size: 14px; color: var(--text-muted); }

/* ===== DOWNLOAD PAGE ===== */
.download-content { padding: 80px 24px; }
.download-main { display: grid; grid-template-columns: repeat(2, 1fr); gap: 32px; max-width: 800px; margin: 0 auto; }
.download-main-card {
    background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius-lg);
    padding: 40px; text-align: center; transition: all 0.3s;
}
.download-main-card:hover { border-color: var(--primary); transform: translateY(-4px); }
.download-main-card .platform-icon { font-size: 48px; margin-bottom: 16px; display: block; }
.download-main-card h3 { font-size: 22px; font-weight: 600; margin-bottom: 8px; }
.download-main-card p { font-size: 14px; color: var(--text-muted); margin-bottom: 24px; }
.download-main-card a {
    display: inline-block; padding: 12px 32px; background: var(--primary);
    color: #0A0A0F !important; font-weight: 600; border-radius: 8px;
    font-size: 15px; transition: all 0.3s;
}
.download-main-card a:hover { background: var(--primary-dark); }

/* ===== LEGAL PAGES ===== */
.legal-content { padding: 80px 24px; }
.legal-body { max-width: 800px; margin: 0 auto; }
.legal-body h3 { font-size: 20px; font-weight: 600; margin: 32px 0 16px; color: var(--primary); }
.legal-body p { font-size: 15px; color: var(--text-secondary); line-height: 1.8; margin-bottom: 16px; }
.legal-body ul { margin: 12px 0 16px 24px; }
.legal-body ul li { font-size: 15px; color: var(--text-secondary); line-height: 1.8; margin-bottom: 8px; }

/* ===== RESPONSIVE ===== */
@media (max-width: 1024px) {
    .value-grid { grid-template-columns: repeat(2, 1fr); }
    .stats-grid { grid-template-columns: repeat(2, 1fr); }
    .download-grid { grid-template-columns: repeat(2, 1fr); }
    .footer-grid { grid-template-columns: repeat(3, 1fr); }
    .feature-block { flex-direction: column !important; gap: 32px; }
    .security-grid { grid-template-columns: 1fr; }
    .help-categories { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
    .nav-links { display: none; }
    .mobile-toggle { display: block; }
    .value-grid { grid-template-columns: 1fr; }
    .stats-grid { grid-template-columns: repeat(2, 1fr); }
    .download-grid { grid-template-columns: 1fr; }
    .footer-grid { grid-template-columns: 1fr 1fr; }
    .footer-bottom { flex-direction: column; text-align: center; }
    .feature-detail-card { flex-direction: column; }
    .help-categories { grid-template-columns: 1fr; }
    .team-grid { grid-template-columns: 1fr; }
    .download-main { grid-template-columns: 1fr; }
    .hero-buttons { flex-direction: column; align-items: center; }
}