/* ===== Glass Mail Product Website — Styles ===== */
:root {
    --primary: #4F46E5;
    --primary-dark: #3730A3;
    --primary-light: #818CF8;
    --accent: #22C55E;
    --bg: #FFFFFF;
    --bg-alt: #F8FAFC;
    --bg-dark: #0F172A;
    --text: #1E293B;
    --text-muted: #64748B;
    --text-light: #94A3B8;
    --border: #E2E8F0;
    --shadow: 0 4px 24px rgba(0,0,0,0.08);
    --radius: 16px;
    --max-width: 1200px;
    --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { font-family: var(--font); color: var(--text); background: var(--bg); line-height: 1.6; -webkit-font-smoothing: antialiased; }
.container { max-width: var(--max-width); margin: 0 auto; padding: 0 24px; }

/* Header */
.header { position: fixed; top: 0; left: 0; right: 0; z-index: 100; background: rgba(255,255,255,0.92); backdrop-filter: blur(20px); border-bottom: 1px solid var(--border); }
.header-content { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.logo { display: flex; align-items: center; gap: 10px; text-decoration: none; }
.logo-icon { width: 36px; height: 36px; background: var(--primary); border-radius: 10px; display: flex; align-items: center; justify-content: center; font-size: 18px; color: #fff; }
.logo-text { font-size: 1.25rem; font-weight: 700; color: var(--text); }
.nav { display: flex; gap: 28px; }
.nav a { text-decoration: none; color: var(--text-muted); font-size: 0.9rem; font-weight: 500; transition: color 0.2s; }
.nav a:hover { color: var(--primary); }
.mobile-menu-btn { display: none; background: none; border: none; font-size: 1.5rem; cursor: pointer; color: var(--text); padding: 8px; }
@media (max-width: 768px) {
    .nav { display: none; position: absolute; top: 64px; left: 0; right: 0; background: #fff; flex-direction: column; padding: 16px 24px; border-bottom: 1px solid var(--border); gap: 12px; }
    .nav.active { display: flex; }
    .mobile-menu-btn { display: block; }
}

/* Hero */
.hero { padding: 140px 0 80px; background: linear-gradient(135deg, #EEF2FF 0%, #F0F9FF 50%, #ECFDF5 100%); text-align: center; }
.hero-badge { display: inline-block; background: var(--primary); color: #fff; padding: 6px 20px; border-radius: 24px; font-size: 0.85rem; font-weight: 600; margin-bottom: 24px; }
.hero-title { font-size: clamp(2.5rem, 5vw, 4rem); font-weight: 800; color: var(--bg-dark); margin-bottom: 16px; }
.hero-subtitle { font-size: clamp(1rem, 2vw, 1.25rem); color: var(--text-muted); max-width: 640px; margin: 0 auto 32px; }
.hero-actions { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; margin-bottom: 48px; }
.btn { display: inline-flex; align-items: center; justify-content: center; padding: 12px 28px; border-radius: 12px; font-size: 1rem; font-weight: 600; text-decoration: none; transition: all 0.2s; cursor: pointer; border: none; }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); transform: translateY(-1px); box-shadow: 0 4px 12px rgba(79,70,229,0.4); }
.btn-secondary { background: #fff; color: var(--primary); border: 2px solid var(--primary); }
.btn-secondary:hover { background: var(--primary); color: #fff; }
.hero-stats { display: flex; justify-content: center; gap: 48px; flex-wrap: wrap; }
.stat { text-align: center; }
.stat-number { font-size: 1.5rem; font-weight: 800; color: var(--primary); }
.stat-label { font-size: 0.85rem; color: var(--text-muted); }

/* Sections */
.section { padding: 80px 0; }
.section-title { font-size: clamp(1.5rem, 3vw, 2rem); font-weight: 700; text-align: center; margin-bottom: 12px; }
.section-subtitle { text-align: center; color: var(--text-muted); margin-bottom: 48px; font-size: 1.05rem; }

/* Features */
.features { background: var(--bg-alt); }
.features-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 24px; }
.feature-card { background: #fff; border-radius: var(--radius); padding: 28px; box-shadow: var(--shadow); transition: transform 0.2s, box-shadow 0.2s; }
.feature-card:hover { transform: translateY(-4px); box-shadow: 0 8px 32px rgba(0,0,0,0.12); }
.feature-icon { font-size: 2rem; margin-bottom: 12px; }
.feature-card h3 { font-size: 1.1rem; font-weight: 600; margin-bottom: 8px; }
.feature-card p { color: var(--text-muted); font-size: 0.9rem; line-height: 1.5; }

/* Screenshots */
.screenshots-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 24px; }
.screenshot-card { border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); }
.screenshot-placeholder { background: linear-gradient(135deg, #EEF2FF, #F0F9FF); height: 220px; display: flex; flex-direction: column; align-items: center; justify-content: center; text-align: center; }
.placeholder-icon { font-size: 3rem; margin-bottom: 8px; }
.placeholder-text { font-size: 1rem; font-weight: 600; color: var(--text); }
.placeholder-hint { font-size: 0.75rem; color: var(--text-light); margin-top: 4px; }
.screenshot-caption { padding: 16px; background: #fff; font-size: 0.9rem; color: var(--text-muted); text-align: center; }

/* Requirements */
.requirements { background: var(--bg-alt); }
.requirements-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 24px; }
.req-card { background: #fff; border-radius: var(--radius); padding: 28px; box-shadow: var(--shadow); }
.req-card h3 { font-size: 1.1rem; font-weight: 600; margin-bottom: 16px; color: var(--primary); }
.req-table { width: 100%; border-collapse: collapse; }
.req-table td { padding: 8px 0; font-size: 0.9rem; border-bottom: 1px solid var(--border); }
.req-table td:first-child { font-weight: 500; color: var(--text); width: 40%; }
.req-table td:last-child { color: var(--text-muted); }
.os-list { list-style: none; padding: 0; }
.os-list li { padding: 8px 0; font-size: 0.9rem; color: var(--text-muted); border-bottom: 1px solid var(--border); }

/* Registry */
.registry-section { background: linear-gradient(135deg, #EEF2FF, #F0F9FF); }
.registry-card { background: #fff; border-radius: var(--radius); padding: 40px; box-shadow: var(--shadow); max-width: 800px; margin: 0 auto; }
.registry-badge { display: inline-block; background: var(--accent); color: #fff; padding: 8px 24px; border-radius: 24px; font-weight: 600; font-size: 0.95rem; margin-bottom: 24px; }
.registry-info { margin-bottom: 32px; }
.registry-row { display: flex; padding: 12px 0; border-bottom: 1px solid var(--border); }
.registry-row:last-child { border-bottom: none; }
.registry-label { font-weight: 500; width: 200px; flex-shrink: 0; color: var(--text-muted); }
.registry-value { font-weight: 600; color: var(--text); }
.registry-advantages h3 { font-size: 1.1rem; font-weight: 600; margin-bottom: 16px; }
.registry-advantages ul { list-style: none; padding: 0; }
.registry-advantages li { padding: 8px 0; font-size: 0.95rem; color: var(--text-muted); }
@media (max-width: 600px) { .registry-label { width: 120px; font-size: 0.85rem; } .registry-value { font-size: 0.9rem; } }

/* Substitution */
.substitution { background: var(--bg); }
.substitution-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; align-items: center; }
.sub-card { text-align: center; padding: 20px; border-radius: var(--radius); }
.sub-card.replaced { background: #FEF2F2; border: 1px solid #FECACA; }
.sub-card.replacement { background: #F0FDF4; border: 1px solid #BBF7D0; }
.sub-card h4 { font-size: 1rem; margin: 8px 0 4px; }
.sub-card p { font-size: 0.85rem; color: var(--text-muted); }
.sub-icon { font-size: 1.5rem; }
.sub-arrow { text-align: center; font-size: 1.5rem; color: var(--text-light); }
@media (max-width: 768px) { .substitution-grid { grid-template-columns: 1fr; } .sub-arrow { transform: rotate(90deg); } }

/* Contacts */
.contacts { background: var(--bg-alt); }
.contacts-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 24px; }
.contact-card { background: #fff; border-radius: var(--radius); padding: 28px; box-shadow: var(--shadow); }
.contact-card h3 { font-size: 1.1rem; font-weight: 600; margin-bottom: 16px; color: var(--primary); }
.contact-row { display: flex; padding: 8px 0; border-bottom: 1px solid var(--border); }
.contact-row:last-child { border-bottom: none; }
.contact-label { font-weight: 500; width: 100px; color: var(--text-muted); flex-shrink: 0; }
.contact-value { color: var(--text); font-weight: 500; }

/* Footer */
.footer { background: var(--bg-dark); color: #CBD5E1; padding: 48px 0 24px; }
.footer-content { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 40px; margin-bottom: 32px; }
.footer-desc { color: #94A3B8; font-size: 0.9rem; margin-top: 12px; line-height: 1.6; }
.footer-links h4 { color: #fff; font-size: 0.95rem; margin-bottom: 12px; }
.footer-links ul { list-style: none; padding: 0; }
.footer-links li { font-size: 0.85rem; margin-bottom: 8px; color: #94A3B8; }
.footer-links a { color: #94A3B8; text-decoration: none; transition: color 0.2s; }
.footer-links a:hover { color: var(--primary-light); }
.footer-bottom { border-top: 1px solid #1E293B; padding-top: 20px; text-align: center; }
.footer-bottom p { font-size: 0.85rem; color: #64748B; margin-bottom: 4px; }
@media (max-width: 768px) { .footer-content { grid-template-columns: 1fr; gap: 24px; } .hero-stats { gap: 24px; } }