:root {
  --bg: #111417;
  --bg-soft: #171b20;
  --panel: rgba(24, 29, 34, 0.92);
  --panel-edge: rgba(131, 148, 164, 0.18);
  --text: #e9eef3;
  --muted: #98a7b8;
  --accent: #8bd3ff;
  --accent-2: #9cffb1;
  --warn: #ffd37a;
  --danger: #ff8d8d;
  --success: #8bf4b2;
  --font-ui: "IBM Plex Sans", "Segoe UI", sans-serif;
  --font-code: "IBM Plex Mono", "JetBrains Mono", monospace;
}

* { box-sizing: border-box; }
html, body {
  margin: 0;
  background:
    radial-gradient(circle at top, rgba(86, 123, 155, 0.18), transparent 28%),
    linear-gradient(180deg, #0f1215 0%, #13181c 100%);
  color: var(--text);
  font-family: var(--font-ui);
  min-height: 100%;
}

body { padding: 0 0 calc(80px + env(safe-area-inset-bottom)); }
a { color: inherit; text-decoration: none; }
code, .eyebrow, .chip, .score, .status, .plan-order { font-family: var(--font-code); }

.app-shell {
  width: min(100%, 720px);
  margin: 0 auto;
  padding: env(safe-area-inset-top) 16px 0;
}

.topbar {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: flex-start;
  padding: 18px 0 10px;
}

.topbar h1 {
  margin: 4px 0 0;
  font-size: 1.5rem;
  line-height: 1.1;
}

.eyebrow {
  color: var(--accent);
  font-size: 0.72rem;
  letter-spacing: 0.14em;
}

.page-content {
  display: grid;
  gap: 14px;
}

.panel {
  background: var(--panel);
  border: 1px solid var(--panel-edge);
  border-radius: 18px;
  padding: 16px;
  backdrop-filter: blur(12px);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.18);
}

.hero-panel {
  background:
    linear-gradient(140deg, rgba(139, 211, 255, 0.08), rgba(156, 255, 177, 0.04)),
    var(--panel);
}

.hero-grid {
  display: grid;
  gap: 16px;
}

.primary-link,
button {
  appearance: none;
  border: 0;
  border-radius: 14px;
  background: linear-gradient(135deg, #78bce3, #94f1bc);
  color: #0f1214;
  font-weight: 700;
  font-size: 0.98rem;
  padding: 13px 16px;
  text-align: center;
}

.secondary-button,
.ghost-button {
  background: rgba(151, 174, 190, 0.12);
  color: var(--text);
  border: 1px solid rgba(151, 174, 190, 0.2);
}

.finish-button { width: 100%; }

.muted {
  color: var(--muted);
  font-size: 0.92rem;
}

.lead { font-size: 1.04rem; }

.stats-grid,
.skill-list {
  display: grid;
  gap: 12px;
}

.stat-card span,
.section-head h2 {
  color: var(--muted);
}

.stat-card strong {
  display: block;
  margin-top: 6px;
  font-size: 1.2rem;
}

.section-head {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: center;
  margin-bottom: 10px;
}

.section-head h2 {
  margin: 0;
  font-size: 0.9rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.chip-row,
.button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.chip {
  display: inline-flex;
  padding: 7px 10px;
  border-radius: 999px;
  background: rgba(139, 211, 255, 0.08);
  border: 1px solid rgba(139, 211, 255, 0.18);
  font-size: 0.76rem;
}

.plan-list,
.compact-list,
.exam-list {
  display: grid;
  gap: 10px;
  margin: 0;
  padding-left: 18px;
}

.plan-item,
.skill-item,
.word-card {
  display: grid;
  gap: 8px;
  padding: 12px;
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.compact.word-card { padding: 10px 12px; }

.plan-item {
  grid-template-columns: 34px 1fr;
  align-items: start;
}

.plan-order {
  width: 34px;
  height: 34px;
  border-radius: 10px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: rgba(139, 211, 255, 0.08);
  color: var(--accent);
}

.skill-head,
.word-head {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: baseline;
}

.status {
  text-transform: uppercase;
  font-size: 0.72rem;
  color: var(--accent-2);
}

.score { color: var(--accent); }

.prompt {
  font-size: 1.05rem;
  margin: 0 0 12px;
}

.answer-form,
.stack-form {
  display: grid;
  gap: 10px;
}

input[type="text"] {
  width: 100%;
  border-radius: 14px;
  border: 1px solid rgba(151, 174, 190, 0.22);
  background: rgba(7, 10, 14, 0.58);
  color: var(--text);
  padding: 14px;
  font-size: 1rem;
}

.hint-box,
.answer-reveal {
  margin-top: 10px;
  padding: 12px;
  border-radius: 12px;
  background: rgba(139, 211, 255, 0.07);
  color: var(--accent);
}

.flash {
  border-radius: 14px;
  padding: 12px 14px;
  margin: 2px 0 14px;
  font-size: 0.94rem;
}

.flash-info { background: rgba(139, 211, 255, 0.1); color: var(--accent); }
.flash-success { background: rgba(139, 244, 178, 0.1); color: var(--success); }
.flash-warning { background: rgba(255, 211, 122, 0.1); color: var(--warn); }
.flash-error { background: rgba(255, 141, 141, 0.1); color: var(--danger); }

.bottom-nav {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 4px;
  width: min(100%, 720px);
  margin: 0 auto;
  padding: 10px 10px calc(10px + env(safe-area-inset-bottom));
  background: rgba(12, 15, 18, 0.9);
  border-top: 1px solid rgba(151, 174, 190, 0.12);
  backdrop-filter: blur(16px);
}

.bottom-nav a {
  text-align: center;
  color: var(--muted);
  font-size: 0.77rem;
  padding: 8px 4px;
}

details summary {
  cursor: pointer;
  color: var(--accent);
}

@media (min-width: 720px) {
  .app-shell { padding-left: 20px; padding-right: 20px; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
}