:root {
    --bg: #f4f7fb;
    --surface: rgba(255,255,255,0.9);
    --text: #1f2937;
    --muted: #5f6c7b;
    --primary: #5865f2;
    --primary-soft: #e8ebff;
    --accent: #14b8a6;
    --border: #dfe6f0;
    --shadow: 0 18px 40px rgba(43, 57, 84, 0.12);
}
body.dark {
    --bg: #0f172a;
    --surface: rgba(15, 23, 42, 0.88);
    --text: #e5eefc;
    --muted: #a7b4c9;
    --primary: #8b9cff;
    --primary-soft: #18213d;
    --accent: #34d399;
    --border: #22314d;
    --shadow: 0 18px 40px rgba(0, 0, 0, 0.35);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
    margin: 0;
    font-family: Inter, Arial, sans-serif;
    background: linear-gradient(180deg, var(--bg), #eef3fb);
    color: var(--text);
}
body.dark { background: linear-gradient(180deg, #0f172a, #111827); }
a { color: inherit; text-decoration: none; }
.topbar {
    position: sticky; top: 0; z-index: 50;
    display: flex; justify-content: space-between; align-items: center;
    padding: 18px 5vw; background: rgba(255,255,255,0.75); backdrop-filter: blur(14px);
    border-bottom: 1px solid var(--border);
}
body.dark .topbar { background: rgba(15,23,42,0.75); }
.logo { font-size: 1.4rem; font-weight: 800; }
.logo span { color: var(--primary); }
nav { display: flex; gap: 18px; flex-wrap: wrap; }
nav a { color: var(--muted); font-weight: 600; }
.hero {
    display: grid; grid-template-columns: 1.3fr 0.9fr; gap: 28px;
    padding: 52px 5vw 22px;
}
.hero h1 { font-size: clamp(2rem, 4vw, 4rem); margin: 10px 0 14px; line-height: 1.05; }
.hero p { color: var(--muted); font-size: 1.05rem; max-width: 800px; }
.tag {
    display: inline-block; padding: 8px 14px; border-radius: 999px; background: var(--primary-soft);
    color: var(--primary); font-weight: 700; font-size: 0.9rem;
}
.hero-actions { display: flex; gap: 14px; flex-wrap: wrap; margin: 26px 0; }
.primary-btn, .secondary-btn, .ghost-btn, .answer-btn, .style-btn {
    border: none; border-radius: 16px; cursor: pointer; font-weight: 700;
}
.primary-btn { background: var(--primary); color: white; padding: 14px 18px; box-shadow: var(--shadow); }
.primary-btn.small { padding: 10px 14px; margin-top: 10px; }
.secondary-btn, .ghost-btn, .answer-btn, .style-btn {
    background: var(--surface); color: var(--text); padding: 14px 18px; border: 1px solid var(--border);
}
.stats { display: flex; gap: 18px; flex-wrap: wrap; margin-top: 16px; }
.stats div {
    background: var(--surface); border: 1px solid var(--border); border-radius: 20px; padding: 14px 18px; min-width: 140px;
}
.stats strong { display: block; font-size: 1.4rem; }
.stats span { color: var(--muted); font-size: 0.9rem; }
.section { padding: 28px 5vw; }
.section-head { text-align: center; margin-bottom: 18px; }
.section-head.left { text-align: left; }
.section-head h2 { font-size: clamp(1.7rem, 3vw, 2.6rem); margin-bottom: 10px; }
.section-head p { color: var(--muted); max-width: 850px; margin: 0 auto; }
.left p { margin-left: 0; }
.card {
    background: var(--surface); border: 1px solid var(--border); border-radius: 28px;
    padding: 22px; box-shadow: var(--shadow);
}
.grid { display: grid; gap: 18px; }
.cards-grid { grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); }
.feature-card ul { padding-left: 18px; color: var(--muted); }
.feature-icon { font-size: 2rem; margin-bottom: 6px; }
.switcher { display: flex; justify-content: center; gap: 12px; }
.switch-btn {
    border: 1px solid var(--border); background: var(--surface); color: var(--text);
    padding: 12px 18px; border-radius: 999px; font-weight: 700; cursor: pointer;
}
.switch-btn.active { background: var(--primary); color: white; }
.hidden { display: none; }
.two-col, .lab-grid, .cabinet-grid { display: grid; gap: 18px; }
.two-col { grid-template-columns: 1.15fr 0.85fr; align-items: start; }
.lab-grid { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.cabinet-grid { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.tool-list { display: grid; gap: 14px; }
.tool-card { display: flex; justify-content: space-between; gap: 12px; align-items: center; }
.tool-card span { color: var(--muted); text-align: right; }
.quiz-buttons { display: flex; gap: 10px; flex-wrap: wrap; margin: 16px 0; }
.result { color: var(--primary); font-weight: 700; min-height: 24px; }
.timeline { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 16px; }
.timeline-item span {
    width: 40px; height: 40px; border-radius: 50%; display: grid; place-items: center; background: var(--primary-soft); color: var(--primary); font-weight: 800;
}
.hero-panel .micro-cards { display: grid; gap: 10px; margin-top: 14px; }
.mini { padding: 12px 14px; border-radius: 16px; background: var(--primary-soft); color: var(--text); font-weight: 700; }
textarea {
    width: 100%; min-height: 120px; padding: 12px 14px; border-radius: 16px; border: 1px solid var(--border);
    background: transparent; color: var(--text); resize: vertical;
}
.forum-posts { display: grid; gap: 12px; margin-top: 14px; }
.forum-post { padding: 12px 14px; border-radius: 16px; background: var(--primary-soft); }
.progress-row { margin: 14px 0; }
.progress-row span { display: inline-block; margin-bottom: 8px; }
.bar { height: 12px; background: #d8deea; border-radius: 999px; overflow: hidden; }
body.dark .bar { background: #22314d; }
.bar div { height: 100%; width: 20%; background: linear-gradient(90deg, var(--primary), var(--accent)); }
.badges { display: flex; gap: 10px; flex-wrap: wrap; }
.badge {
    padding: 10px 12px; border-radius: 999px; background: var(--primary-soft); color: var(--primary); font-weight: 800;
}
.toggle-line { display: flex; gap: 10px; align-items: center; margin-top: 10px; }
.footer { padding: 24px 5vw 50px; color: var(--muted); text-align: center; }
blockquote {
    margin: 14px 0; padding: 12px 16px; border-left: 4px solid var(--primary);
    background: var(--primary-soft); border-radius: 12px;
}
@media (max-width: 920px) {
    .hero, .two-col { grid-template-columns: 1fr; }
    .topbar { flex-direction: column; gap: 12px; }
}