/* .NET Interview Trainer — mobile-first PWA styles */

:root {
  --bg: #f4f4f7;
  --card: #ffffff;
  --text: #1c1c26;
  --muted: #6b6b7a;
  --border: #e2e2ea;
  --accent: #4f46e5;
  --accent-text: #ffffff;
  --success: #16a34a;
  --success-soft: #dcfce7;
  --warning: #d97706;
  --warning-soft: #fef3c7;
  --danger: #dc2626;
  --info: #0891b2;
  --code-bg: #1e1e2e;
  --code-text: #e4e4f0;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.07);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111118;
    --card: #1c1c26;
    --text: #ececf2;
    --muted: #9a9aac;
    --border: #2e2e3c;
    --accent: #818cf8;
    --accent-text: #111118;
    --success: #4ade80;
    --success-soft: #14321f;
    --warning: #fbbf24;
    --warning-soft: #37290e;
    --danger: #f87171;
    --info: #22d3ee;
    --code-bg: #0d0d14;
    --code-text: #d4d4e4;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.4);
  }
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  padding-top: env(safe-area-inset-top);
}

#app {
  max-width: 720px;
  margin: 0 auto;
  padding: 16px 16px calc(84px + env(safe-area-inset-bottom));
}

h1 { font-size: 1.45rem; margin: 0.2em 0; }
h2 { font-size: 1.25rem; margin: 0.4em 0 0.8em; }
h4 { margin: 1.4em 0 0.6em; }

a { color: var(--accent); text-decoration: none; }

.muted { color: var(--muted); }
.small { font-size: 0.85rem; }

/* ---------- Loading ---------- */
.loading { text-align: center; padding: 4rem 0; color: var(--muted); }
.spinner {
  width: 36px; height: 36px; margin: 0 auto 12px;
  border: 3px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ---------- Hero ---------- */
.hero {
  background: linear-gradient(135deg, #4f46e5, #7c3aed);
  color: #fff;
  border-radius: 16px;
  padding: 20px;
  margin-bottom: 16px;
}
.hero p { margin: 0.4em 0 0; opacity: 0.9; font-size: 0.95rem; }

/* ---------- Cards & grids ---------- */
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 16px;
  box-shadow: var(--shadow);
}

.stat-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  margin-bottom: 16px;
}
@media (min-width: 560px) { .stat-grid { grid-template-columns: repeat(4, 1fr); } }

.stat-card { text-align: center; padding: 12px 8px; }
.stat-number { font-size: 1.7rem; font-weight: 700; }
.stat-number.success { color: var(--success); }
.stat-number.warning { color: var(--warning); }

.progress-track {
  background: var(--border);
  border-radius: 99px;
  height: 12px;
  overflow: hidden;
}
.progress-fill {
  background: var(--success);
  height: 100%;
  border-radius: 99px;
  transition: width 0.4s ease;
}
.progress-fill.info { background: var(--info); }

.action-grid { display: grid; gap: 12px; margin: 16px 0 8px; }
@media (min-width: 560px) { .action-grid { grid-template-columns: 1fr 1fr; } }
.action-card { cursor: pointer; }
.action-card h3 { margin: 0 0 6px; font-size: 1.05rem; }
.action-card p { margin: 0 0 10px; color: var(--muted); font-size: 0.9rem; }

.category-grid { display: grid; gap: 8px; }
@media (min-width: 560px) { .category-grid { grid-template-columns: 1fr 1fr; } }
.category-card {
  display: flex; justify-content: space-between; align-items: center;
  padding: 12px 16px; cursor: pointer;
}
.category-card:active { opacity: 0.7; }

/* ---------- Badges & buttons ---------- */
.badge {
  display: inline-block;
  padding: 2px 9px;
  border-radius: 99px;
  font-size: 0.72rem;
  font-weight: 600;
  vertical-align: middle;
}
.badge.cat { background: var(--border); color: var(--text); }
.badge.easy { background: var(--success); color: #fff; }
.badge.medium { background: var(--info); color: #fff; }
.badge.hard { background: var(--warning); color: #fff; }
.badge.senior { background: var(--danger); color: #fff; }
.badge.known { background: var(--success-soft); color: var(--success); }
.badge.review { background: var(--warning-soft); color: var(--warning); }
.badge.pill { background: var(--accent); color: var(--accent-text); }
.badge.tag { background: transparent; border: 1px solid var(--border); color: var(--muted); font-weight: 400; }

.btn {
  display: inline-block;
  border: 1px solid transparent;
  border-radius: 10px;
  padding: 9px 16px;
  font-size: 0.9rem;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}
.btn:active { opacity: 0.75; }
.btn.primary { background: var(--accent); color: var(--accent-text); }
.btn.success { background: var(--success); color: #fff; }
.btn.warning { background: var(--warning); color: #fff; }
.btn.outline { background: transparent; border-color: var(--border); color: var(--text); }
.btn.sm { padding: 6px 12px; font-size: 0.82rem; }
.btn.block { display: block; width: 100%; text-align: center; }
.btn:disabled { opacity: 0.45; cursor: default; }

/* ---------- Forms ---------- */
.field { margin-bottom: 12px; }
.field label { display: block; font-size: 0.8rem; color: var(--muted); margin-bottom: 4px; }
input[type="text"], input[type="search"], input[type="password"], select {
  width: 100%;
  padding: 10px 12px;
  font-size: 16px; /* prevents iOS zoom on focus */
  font-family: inherit;
  color: var(--text);
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  appearance: none;
  -webkit-appearance: none;
}
input[type="range"] { width: 100%; accent-color: var(--accent); }

.filter-bar { margin-bottom: 14px; }
.filter-row { display: grid; gap: 10px; }
@media (min-width: 560px) { .filter-row { grid-template-columns: 2fr 2fr 1fr 1fr; align-items: end; } }

.toolbar {
  display: flex; justify-content: space-between; align-items: center;
  margin-bottom: 12px;
}

/* ---------- Question card ---------- */
.question-card { margin-bottom: 12px; border-left: 4px solid transparent; }
.question-card.known { border-left-color: var(--success); }
.question-card.review { border-left-color: var(--warning); }

.qc-head {
  display: flex; justify-content: space-between; align-items: flex-start;
  gap: 8px; flex-wrap: wrap;
}
.qc-badges { display: flex; gap: 6px; flex-wrap: wrap; align-items: center; }
.qc-title { font-size: 1rem; font-weight: 600; margin: 10px 0 12px; }

.answer-text { white-space: pre-line; font-size: 0.93rem; margin: 0 0 4px; }

.key-points {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px 14px;
  margin-top: 12px;
  font-size: 0.9rem;
}
.key-points ul { margin: 6px 0 0; padding-left: 18px; }
.key-points li { margin-bottom: 3px; }

pre.code-example {
  background: var(--code-bg);
  color: var(--code-text);
  border-radius: 10px;
  padding: 12px;
  overflow-x: auto;
  font-size: 0.8rem;
  line-height: 1.45;
  margin: 12px 0 0;
}

.qc-tags { margin-top: 12px; display: flex; gap: 5px; flex-wrap: wrap; }

.self-assess {
  margin-top: 14px; padding-top: 12px;
  border-top: 1px solid var(--border);
  display: flex; align-items: center; gap: 8px; flex-wrap: wrap;
}

/* ---------- Quiz ---------- */
.quiz-setup { max-width: 480px; margin: 0 auto; }
.quiz-meta { display: flex; justify-content: space-between; color: var(--muted); font-size: 0.88rem; margin-bottom: 8px; }
.quiz-nav { display: flex; justify-content: space-between; margin-top: 14px; }
.range-labels { display: flex; justify-content: space-between; font-size: 0.8rem; color: var(--muted); }

.result-card { max-width: 480px; margin: 0 auto; text-align: center; padding: 28px 20px; }
.result-score { font-size: 3rem; font-weight: 800; margin: 8px 0; }
.result-score.good { color: var(--success); }
.result-score.mid { color: var(--warning); }
.result-score.bad { color: var(--danger); }
.result-breakdown { display: flex; justify-content: space-around; margin: 20px 0; }
.result-breakdown .h4 { font-size: 1.3rem; font-weight: 700; margin: 0; }
.result-actions { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; }

.alert {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px 16px;
  color: var(--muted);
}

/* ---------- Bottom tab bar ---------- */
.tabbar {
  position: fixed;
  bottom: 0; left: 0; right: 0;
  display: flex;
  background: var(--card);
  border-top: 1px solid var(--border);
  padding-bottom: env(safe-area-inset-bottom);
  z-index: 10;
}
.tab {
  flex: 1;
  display: flex; flex-direction: column; align-items: center;
  gap: 1px;
  padding: 8px 0 6px;
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--muted);
  -webkit-tap-highlight-color: transparent;
}
.tab.active { color: var(--accent); }
.tab-icon { font-size: 1.3rem; line-height: 1.2; }

body.locked .tabbar { display: none; }