:root {
  color-scheme: light dark;
  --bg: #f5f7fa;
  --surface: #ffffff;
  --line: #e2e8f0;
  --line-strong: #cbd5e1;
  --text: #0f1b2d;
  --muted: #5a6779;
  --accent: #12355b;
  --accent-hover: #0c2742;
  --accent-text: #12355b;
  --on-accent: #ffffff;
  --tint: #edf2f8;
  --warn-bg: #fff8e8;
  --warn-line: #f0dba6;
  --warn-text: #6a4a00;
  --radius: 12px;
  --font: Inter, system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b1220;
    --surface: #111a2b;
    --line: #1f2c42;
    --line-strong: #2d3d58;
    --text: #e8edf5;
    --muted: #93a1b5;
    --accent: #2f6db3;
    --accent-hover: #285f9f;
    --accent-text: #cfe0f5;
    --tint: #10203a;
    --warn-bg: #2a2210;
    --warn-line: #5a4a1c;
    --warn-text: #f3d98b;
  }
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; font-size: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 400 0.9375rem/1.6 var(--font);
  -webkit-font-smoothing: antialiased;
}
h1, h2, h3, p, dl, dd, ul { margin: 0; padding: 0; }
a { color: inherit; }
img, svg { max-width: 100%; }
.app-card, .hero-item, .info > *, .step-content, .build { min-width: 0; }
.app-card__name, .app-card__tagline, .build-meta, .build-note, .download-btn, .step-content, .support-card a, .qr-hint, .hero-title, .hero-hint, .section-title { overflow-wrap: anywhere; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

.container { max-width: 1080px; margin: 0 auto; padding: 48px 24px 64px; }

/* ---------- Header ---------- */
.header {
  display: flex; flex-wrap: wrap; align-items: flex-end; justify-content: space-between;
  gap: 12px 24px; padding-bottom: 28px; border-bottom: 1px solid var(--line);
}
.app-title { font-size: clamp(28px, 4vw, 38px); line-height: 1.15; font-weight: 650; letter-spacing: -0.02em; }
.app-subtitle { margin-top: 10px; color: var(--muted); font-size: 1rem; }
.updated { color: var(--muted); font-size: 0.8125rem; font-variant-numeric: tabular-nums; }
.updated:empty { display: none; }

.section-title { font-size: 1.25rem; font-weight: 600; letter-spacing: -0.01em; margin: 48px 0 16px; }

/* ---------- Gợi ý theo thiết bị ---------- */
.hero { margin-top: 28px; }
.hero[hidden] { display: none; }
.hero-card { background: var(--tint); border: 1px solid var(--line); border-radius: var(--radius); padding: 24px; }
.hero-eyebrow { font-size: 0.75rem; font-weight: 600; letter-spacing: 0.08em; text-transform: uppercase; color: var(--accent-text); }
.hero-title { font-size: 1.25rem; font-weight: 600; margin-top: 4px; }
.hero-hint { color: var(--muted); margin-top: 2px; }
.hero-items { display: grid; gap: 20px; grid-template-columns: repeat(auto-fit, minmax(min(100%, 260px), 1fr)); margin-top: 20px; }
.hero-item { display: grid; grid-template-columns: minmax(0, 1fr); gap: 8px; align-content: start; }

/* ---------- Lưới app ---------- */
.app-grid {
  display: grid; gap: 16px;
  grid-template-columns: repeat(auto-fill, minmax(min(100%, 340px), 1fr));
}
.app-card {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 20px; display: flex; flex-direction: column; gap: 16px;
  scroll-margin-top: 24px; transition: border-color 0.15s, box-shadow 0.15s;
}
.app-card:target,
.app-card.is-target {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 18%, transparent);
}
.app-card__head { display: flex; align-items: center; gap: 12px; }
.app-card__icon { width: 44px; height: 44px; border-radius: 11px; object-fit: cover; flex: none; border: 1px solid var(--line); }
.app-card__name { font-size: 1rem; font-weight: 600; line-height: 1.3; }
.app-card__tagline { color: var(--muted); font-size: 0.8125rem; line-height: 1.4; margin-top: 2px; }

.build { display: grid; grid-template-columns: minmax(0, 1fr); gap: 8px; border-top: 1px solid var(--line); padding-top: 16px; }
.build-meta { color: var(--muted); font-size: 0.7812rem; line-height: 1.5; font-variant-numeric: tabular-nums; }
.build-note { color: var(--muted); font-size: 0.7812rem; line-height: 1.5; }

/* ---------- Nút tải ---------- */
.download-btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  min-height: 44px; padding: 10px 16px; border-radius: 10px;
  border: 1px solid var(--accent); background: var(--accent); color: var(--on-accent);
  font: 500 0.875rem/1.25 var(--font); text-align: center; text-decoration: none;
  transition: background-color 0.15s, border-color 0.15s;
}
.download-btn:hover { background: var(--accent-hover); border-color: var(--accent-hover); }
.download-btn svg { width: 18px; height: 18px; flex: none; }
.download-btn--secondary { background: transparent; color: var(--accent-text); }
.download-btn--secondary:hover { background: var(--tint); border-color: var(--accent); }
.download-btn--lg { min-height: 48px; font-size: 0.9375rem; }

/* ---------- Hướng dẫn ---------- */
.guide-list { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; }
.guide-card + .guide-card { border-top: 1px solid var(--line); }
.guide-card summary {
  display: flex; align-items: center; gap: 12px; padding: 16px 20px;
  cursor: pointer; list-style: none; font-weight: 500;
}
.guide-card summary::-webkit-details-marker { display: none; }
.guide-card summary:hover { background: var(--tint); }
.guide-card summary::after {
  content: ''; margin-left: auto; width: 7px; height: 7px; flex: none;
  border-right: 1.5px solid var(--muted); border-bottom: 1.5px solid var(--muted);
  transform: rotate(45deg) translateY(-2px); transition: transform 0.15s;
}
.guide-card[open] summary::after { transform: rotate(-135deg) translateY(-2px); }
.guide-icon { display: inline-flex; color: var(--muted); }
.guide-icon svg { width: 20px; height: 20px; }
.guide-body { padding: 4px 20px 24px 52px; }
@media (max-width: 560px) { .guide-body { padding-left: 20px; } }

.steps-container { display: grid; gap: 16px; }
.step-card { display: flex; gap: 14px; }
.step-number {
  flex: none; width: 26px; height: 26px; border: 1px solid var(--line-strong); border-radius: 50%;
  display: grid; place-items: center; font-size: 0.75rem; font-weight: 600; color: var(--muted);
  font-variant-numeric: tabular-nums;
}
.step-content h3 { font-size: 0.9375rem; font-weight: 600; line-height: 1.4; margin-bottom: 2px; }
.step-content p { color: var(--muted); }
.step-content b { color: var(--text); font-weight: 600; }
.step-content code, .note code {
  background: var(--tint); padding: 1px 6px; border-radius: 6px;
  font: 500 0.9em ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}
.note {
  background: var(--warn-bg); border: 1px solid var(--warn-line); border-radius: 10px;
  padding: 12px 14px; color: var(--warn-text); font-size: 0.875rem; margin-bottom: 20px;
}
.guide-images { display: grid; gap: 12px; margin-top: 20px; grid-template-columns: repeat(auto-fit, minmax(min(100%, 140px), 1fr)); }
.guide-images img { width: 100%; border-radius: 10px; border: 1px solid var(--line); display: block; }

/* ---------- Fallback ---------- */
.fallback-card { background: var(--warn-bg); border: 1px solid var(--warn-line); border-radius: var(--radius); padding: 20px 24px; margin-top: 24px; }
.fallback-card[hidden] { display: none; }
.fallback-card h2 { font-size: 1rem; font-weight: 600; color: var(--warn-text); }
.fallback-card p { color: var(--warn-text); margin: 4px 0 12px; }
.fallback-card ul { list-style: none; display: grid; gap: 8px; }
.fallback-card a { color: var(--warn-text); font-weight: 600; }

/* ---------- QR + Hỗ trợ ---------- */
.info { display: grid; gap: 0 48px; grid-template-columns: 1fr; }
@media (min-width: 760px) { .info { grid-template-columns: 1fr 1fr; } }
.qr-section { display: flex; align-items: center; gap: 20px; }
.qr-container { flex: none; background: #fff; border: 1px solid var(--line); border-radius: 10px; padding: 8px; }
.qr-container img { display: block; width: 112px; height: 112px; }
.qr-hint { color: var(--muted); font-size: 0.875rem; }
.support-grid { display: grid; gap: 12px; }
.support-card { display: grid; grid-template-columns: minmax(0, 1fr); gap: 0; }
.support-label { color: var(--muted); font-size: 0.8125rem; }
.support-card a { font-weight: 500; font-size: 1rem; text-decoration: none; width: fit-content; }
.support-card a:hover { text-decoration: underline; text-underline-offset: 3px; }

/* ---------- Footer ---------- */
.footer { margin-top: 56px; padding-top: 20px; border-top: 1px solid var(--line); color: var(--muted); font-size: 0.8125rem; }
.loading { color: var(--muted); }

@media (max-width: 560px) {
  .container { padding: 32px 20px 48px; }
  .hero-card { padding: 20px; }
}
@media (prefers-reduced-motion: reduce) { * { transition: none !important; } }

.view-toggle { display: block; margin: 16px auto 0; padding: 8px; background: none; border: 0; color: var(--accent-text); font: inherit; text-decoration: underline; cursor: pointer; }