:root {
  --bg: #0d1117;
  --panel: #161b22;
  --panel-2: #1f2730;
  --line: #30363d;
  --ink: #e6edf3;
  --muted: #8b949e;
  --accent: #58a6ff;
  --good: #3fb950;
  --bad: #f85149;
  --warn: #d29922;
  --shield: #d9534f;
  --shield-blue: #1e63d6;
  --mono: ui-monospace, SFMono-Regular, "JetBrains Mono", Menlo, Consolas, monospace;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f6f8fa;
    --panel: #ffffff;
    --panel-2: #f0f3f6;
    --line: #d0d7de;
    --ink: #1f2328;
    --muted: #57606a;
    --accent: #0969da;
  }
}

* { box-sizing: border-box; }

[hidden] { display: none !important; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.5;
}

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.75rem 1.25rem;
  border-bottom: 1px solid var(--line);
  background: var(--panel);
  position: sticky;
  top: 0;
  z-index: 10;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 700;
  text-decoration: none;
  color: var(--ink);
  font-size: 1.05rem;
}

.shield {
  display: inline-grid;
  place-items: center;
  width: 28px;
  height: 32px;
  background: var(--shield);
  color: #fff;
  font-weight: 800;
  font-size: 0.85rem;
  border-radius: 4px 4px 14px 14px;
  border: 2px solid #fff;
  outline: 1px solid var(--ink);
}

nav { display: flex; gap: 0.25rem; }

nav a {
  padding: 0.4rem 0.8rem;
  border-radius: 6px;
  text-decoration: none;
  color: var(--muted);
  font-weight: 500;
}

nav a:hover { color: var(--ink); background: var(--panel-2); }
nav a.active { color: var(--accent); background: var(--panel-2); }

main {
  max-width: 960px;
  margin: 0 auto;
  padding: 2rem 1.25rem 4rem;
}

h1 { font-size: 1.75rem; margin: 0 0 0.25rem; }
.subtitle { color: var(--muted); margin: 0 0 1.5rem; }

footer {
  text-align: center;
  color: var(--muted);
  font-size: 0.85rem;
  padding: 1.5rem;
  border-top: 1px solid var(--line);
}

.card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 1.25rem;
}

.card + .card { margin-top: 1rem; }

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1rem;
}

.card a.cta {
  display: inline-block;
  margin-top: 0.75rem;
  color: var(--accent);
  text-decoration: none;
  font-weight: 600;
}
.card a.cta:hover { text-decoration: underline; }

.prompt {
  font-size: 1.25rem;
  margin: 0 0 1rem;
}

.prompt .big {
  font-family: var(--mono);
  font-weight: 700;
  color: var(--accent);
}

input[type="text"], textarea {
  width: 100%;
  padding: 0.6rem 0.75rem;
  border-radius: 8px;
  background: var(--panel-2);
  color: var(--ink);
  border: 1px solid var(--line);
  font-family: var(--mono);
  font-size: 1rem;
}

input[type="text"]:focus, textarea:focus {
  outline: none;
  border-color: var(--accent);
}

.options {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.5rem;
}

.options button {
  padding: 0.5rem 0.9rem;
  border-radius: 8px;
  border: 1px solid var(--line);
  background: var(--panel-2);
  color: var(--ink);
  font-size: 0.95rem;
  cursor: pointer;
}

.options button:hover { border-color: var(--accent); }

.options button.selected {
  border-color: var(--accent);
  background: rgba(88, 166, 255, 0.12);
  color: var(--accent);
}

.row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: center;
}

.row label { color: var(--muted); font-size: 0.9rem; }

button.primary, a.primary {
  padding: 0.6rem 1rem;
  border-radius: 8px;
  border: 1px solid var(--accent);
  background: var(--accent);
  color: #fff;
  font-weight: 600;
  cursor: pointer;
  text-decoration: none;
  display: inline-block;
}

button.primary:hover, a.primary:hover { filter: brightness(1.05); }

button.ghost, a.ghost {
  padding: 0.6rem 1rem;
  border-radius: 8px;
  border: 1px solid var(--line);
  background: transparent;
  color: var(--ink);
  cursor: pointer;
  text-decoration: none;
  display: inline-block;
}

.verdict {
  margin-top: 1rem;
  padding: 0.9rem 1rem;
  border-radius: 8px;
  border: 1px solid var(--line);
}

.verdict.good { border-color: var(--good); background: rgba(63, 185, 80, 0.10); }
.verdict.bad  { border-color: var(--bad);  background: rgba(248, 81, 73, 0.10); }
.verdict.warn { border-color: var(--warn); background: rgba(210, 153, 34, 0.10); }

.verdict h3 { margin: 0 0 0.3rem; font-size: 1rem; }
.verdict ul { margin: 0.4rem 0 0 1rem; padding: 0; }

.score {
  font-family: var(--mono);
  font-size: 0.9rem;
  color: var(--muted);
}

.transfers {
  font-family: var(--mono);
  font-size: 0.95rem;
  margin-top: 0.5rem;
  color: var(--muted);
}

.transfers .pill {
  display: inline-block;
  padding: 0.1rem 0.5rem;
  border-radius: 999px;
  background: var(--panel-2);
  color: var(--ink);
  border: 1px solid var(--line);
  margin: 0 0.2rem;
}

.hint {
  margin-top: 0.5rem;
  font-size: 0.85rem;
  color: var(--muted);
}

.stars {
  font-family: var(--mono);
  letter-spacing: 0.05em;
  color: var(--warn);
  font-size: 0.95rem;
  white-space: nowrap;
}

.mastery {
  display: inline-flex;
  align-items: center;
}

.srs-feedback {
  margin: 0.6rem 0 0;
  padding-top: 0.6rem;
  border-top: 1px solid var(--line);
  font-family: var(--mono);
  font-size: 0.85rem;
  color: var(--muted);
}

.srs-feedback b {
  color: var(--ink);
}

.progress-bar {
  width: 100%;
  height: 10px;
  background: var(--panel-2);
  border-radius: 999px;
  overflow: hidden;
  margin-top: 0.4rem;
}

.progress-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--good));
  transition: width 0.4s;
}

.progress-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 0.5rem;
}

.progress-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.5rem 0.75rem;
  background: var(--panel-2);
  border: 1px solid var(--line);
  border-radius: 8px;
  font-family: var(--mono);
  font-size: 0.85rem;
}

.progress-row.due { border-color: var(--warn); }
.progress-row.mastered { border-color: var(--good); }
.progress-row.fresh { opacity: 0.55; }

.progress-row .due-tag {
  font-size: 0.75rem;
  color: var(--muted);
}

.stat-pills {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-top: 0.5rem;
}

.stat-pill {
  padding: 0.4rem 0.8rem;
  border-radius: 999px;
  background: var(--panel-2);
  border: 1px solid var(--line);
  font-family: var(--mono);
  font-size: 0.85rem;
  color: var(--muted);
}

.stat-pill b { color: var(--ink); font-size: 1.05rem; }
.stat-pill.due { border-color: var(--warn); }
.stat-pill.due b { color: var(--warn); }
.stat-pill.mastered { border-color: var(--good); }
.stat-pill.mastered b { color: var(--good); }

details {
  margin-top: 0.75rem;
}

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

summary:hover { color: var(--ink); }

.schematic {
  width: 100%;
  height: auto;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--panel);
}

.shield-pill {
  display: inline-grid;
  place-items: center;
  min-width: 32px;
  height: 22px;
  background: var(--shield);
  color: #fff;
  font-weight: 700;
  font-size: 0.75rem;
  border-radius: 4px;
  border: 1.5px solid #fff;
  outline: 1px solid var(--ink);
  font-family: var(--mono);
  padding: 0 0.3rem;
}