/* ============================================================
   HSK 1 — Shared stylesheet
   - Reset + theme variables
   - Shell (header, footer, nav)
   - Grammar app base styles
   - Vocab app styles (overrides scoped by [data-app="vocab"])
   ============================================================ */

/* ==== Reset & base ==== */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: #1a1a1a;
  background: #faf7f5;
  line-height: 1.5;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}
h1, h2, h3, h4 { margin: 0 0 .4em; line-height: 1.25; }
p { margin: 0 0 .6em; }
button { font: inherit; cursor: pointer; }
kbd {
  display: inline-block;
  font-family: ui-monospace, Menlo, monospace;
  font-size: 11px;
  background: rgba(0,0,0,.12);
  color: inherit;
  padding: 1px 6px;
  border-radius: 4px;
  border: 1px solid rgba(0,0,0,.1);
  margin-left: 4px;
}
.hidden { display: none !important; }

/* ==== Theme ==== */
:root {
  --accent: #c8102e;
  --accent-light: #fde6e9;
  --accent-dark: #8b0a1e;
  --text: #1a1a1a;
  --text-soft: #6b6b6b;
  --bg: #faf7f5;
  --card-bg: #ffffff;
  --border: #e6e0dd;
  --success: #0a8a4a;
  --success-bg: #e7f6ed;
  --error: #c8102e;
  --error-bg: #fde6e9;
  --warning: #b67c0b;
  --warning-bg: #fdf4dd;
  --info: #1a73a7;
  --info-bg: #e3f1f8;
  --cram-orange: #ff6b35;
  --radius: 12px;
  --radius-lg: 18px;
  --shadow-sm: 0 1px 2px rgba(0,0,0,.04), 0 2px 4px rgba(0,0,0,.04);
  --shadow: 0 4px 12px rgba(0,0,0,.06);
  --shadow-lg: 0 8px 24px rgba(0,0,0,.08);
}

/* ==== Shell: header + nav + footer ==== */
.app-header {
  background: linear-gradient(135deg, var(--accent) 0%, var(--accent-dark) 100%);
  color: #fff;
  padding: 14px 20px 10px;
  position: sticky;
  top: 0;
  z-index: 50;
  box-shadow: var(--shadow);
}
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 10px;
}
.logo {
  width: 42px;
  height: 42px;
  background: rgba(255,255,255,.18);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 26px;
  font-weight: 700;
  font-family: "PingFang SC", "Microsoft YaHei", serif;
}
.app-header h1 { font-size: 17px; margin: 0; font-weight: 600; }
.tagline { font-size: 12px; opacity: .8; margin: 0; }
.top-nav { display: flex; gap: 6px; flex-wrap: wrap; }
.nav-btn {
  background: rgba(255,255,255,.15);
  color: #fff;
  border: 0;
  padding: 6px 12px;
  border-radius: 999px;
  font-size: 13px;
  transition: all .15s;
}
.nav-btn:hover { background: rgba(255,255,255,.28); }
.nav-btn.active { background: #fff; color: var(--accent); font-weight: 600; }

.app-footer {
  text-align: center;
  padding: 20px 16px;
  color: var(--text-soft);
  font-size: 12px;
  border-top: 1px solid var(--border);
  margin-top: 40px;
}

/* ==== Backup / restore bar (footer) ==== */
.backup-bar {
  margin-top: 14px;
  padding: 10px 12px;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 8px 12px;
  font-size: 12px;
  box-shadow: var(--shadow-sm);
  text-align: left;
}
.backup-info {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
  flex: 1 1 220px;
}
.backup-label {
  font-weight: 600;
  color: var(--text);
  font-size: 12px;
}
.backup-status {
  font-size: 11px;
  word-break: break-word;
  transition: color .15s;
}
.backup-status.is-ok { color: var(--success); }
.backup-status.is-err { color: var(--error); }
.backup-status.is-info { color: var(--info); }
.backup-actions {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}
.backup-bar .ghost-btn {
  font-size: 12px;
  padding: 5px 10px;
}
.backup-bar.is-drag {
  border-color: var(--accent);
  background: var(--accent-light);
  box-shadow: 0 0 0 3px rgba(200, 16, 46, 0.12);
}
@media (max-width: 480px) {
  .backup-bar { font-size: 11px; }
  .backup-info { flex-basis: 100%; }
  .backup-actions { width: 100%; justify-content: flex-end; }
}

/* ==== Main container + views ==== */
#app { max-width: 920px; margin: 0 auto; padding: 20px 16px 80px; width: 100%; }
.view { display: block; animation: fade-in .25s ease-out; }
.view[hidden] { display: none; }
@keyframes fade-in { from { opacity: 0; transform: translateY(4px); } to { opacity: 1; transform: none; } }

.hero h2 { font-size: 22px; color: var(--accent); }
.hero p { color: var(--text-soft); margin-bottom: 20px; }
.muted { color: var(--text-soft); font-size: 13px; }

/* ==== Page layout template ==== */
.page { display: flex; flex-direction: column; }
.page-bar { margin-bottom: 18px; }
.page-head .hero { margin-bottom: 0; }
.page-head .hero p:last-child { margin-bottom: 20px; }
.page-body { flex: 1; }
.page-foot {
  margin-top: 24px;
  padding-top: 16px;
  border-top: 1px dashed var(--border);
}

/* ==== Quick nav trong home view (link sang answer / stats) ==== */
.quick-nav {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}
.view-link {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-soft);
  padding: 8px 14px;
  border-radius: 999px;
  font-size: 13px;
  transition: all .12s;
}
.view-link:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-light);
}