:root {
  --bg: #000;
  --card: #161616;
  --elev: #141414;
  --ink: #fff;
  --muted: #9a9a9a;
  --border: #2a2a2a;
  --accent: #f5c518;
  --accent-ink: #111;
  --cyan: #3de0ff;
  --mint: #5dffb0;
  --pink: #ff5cab;
  --orange: #ff8a3d;
  --bad: #ff5c6a;
  --sans: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  --radius: 14px;
}

* { box-sizing: border-box; }
html { font-size: 17px; }
body {
  margin: 0;
  min-height: 100vh;
  background: #000;
  color: var(--ink);
  font-family: var(--sans);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; }

.wrap { max-width: 42rem; margin: 0 auto; padding: 1.5rem 1.15rem 4rem; }
.wrap-wide { max-width: 52rem; margin: 0 auto; padding: 0 1.15rem 4rem; }

h1, h2, h3 { margin: 0 0 0.6rem; font-weight: 800; letter-spacing: -0.01em; line-height: 1.25; }
h1 { font-size: 1.7rem; }
h2 { font-size: 1.1rem; margin-top: 1.4rem; }
p { margin: 0.55rem 0; }
.lede { color: var(--muted); }
.muted { color: var(--muted); font-size: 0.9rem; }

.topbar {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1rem;
  font-size: 0.9rem;
  color: var(--muted);
}
.topbar a { color: var(--muted); }
.topbar a:hover { color: var(--accent); }

.hero {
  padding: 1.4rem 1.15rem 0.85rem;
}
.hero-inner { max-width: 52rem; margin: 0 auto; }
.hero-top {
  display: flex;
  justify-content: flex-end;
  align-items: flex-start;
  gap: 0.55rem;
  margin-bottom: 0.85rem;
}
.brand {
  font-size: clamp(1.85rem, 5vw, 2.4rem);
  font-weight: 800;
  margin: 0 0 0.35rem;
}
.brand span {
  background: linear-gradient(90deg, var(--accent), var(--pink), var(--cyan));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.ver-mount {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}
.ver-chip {
  font-family: ui-monospace, Consolas, monospace;
  font-size: 0.78rem;
  font-weight: 800;
  color: var(--accent);
  letter-spacing: 0.03em;
}
.ver-btn {
  padding: 0.28rem 0.55rem !important;
  font-size: 0.75rem !important;
  border-radius: 8px !important;
}

.sync-fold {
  position: relative;
}
.sync-fold > summary {
  list-style: none;
  cursor: pointer;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--muted);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.28rem 0.55rem;
  user-select: none;
}
.sync-fold > summary::-webkit-details-marker { display: none; }
.sync-fold[open] > summary { color: var(--cyan); border-color: #444; }
.sync-fold-body {
  position: absolute;
  right: 0;
  top: calc(100% + 6px);
  z-index: 20;
  width: min(92vw, 22rem);
  background: #121212;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 0.75rem;
  box-shadow: 0 12px 32px rgba(0,0,0,.45);
}

.home-main { padding-top: 0.5rem; }
.review-cta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin: 0 0 1.35rem;
  padding: 1rem 1.1rem;
  border-radius: var(--radius);
  background: var(--accent);
  color: var(--accent-ink);
  font-weight: 800;
  font-size: 1.05rem;
}
.review-cta em {
  font-style: normal;
  font-family: ui-monospace, Consolas, monospace;
  font-size: 1.25rem;
  opacity: 0.85;
}
.review-cta.has-due em { opacity: 1; }

.continue-cta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  margin: -0.55rem 0 1.25rem;
  padding: 0.85rem 1.05rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--elev);
  color: inherit;
  font-weight: 700;
}
.continue-cta span { color: var(--cyan); }
.continue-cta em {
  font-style: normal;
  color: #ddd;
  font-weight: 600;
  font-size: 0.92rem;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  max-width: 60%;
}
.overall {
  margin: 0.35rem 0 0;
  color: var(--muted);
  font-size: 0.85rem;
}
.related { margin: 0 0 0.9rem; }
.related-link {
  display: block;
  padding: 0.7rem 0.85rem;
  border: 1px dashed rgba(61,224,255,.35);
  border-radius: 10px;
  color: var(--cyan);
  font-size: 0.9rem;
  font-weight: 700;
}
.goal-list a.is-next { border-color: rgba(245,197,24,.55); }

.shelf-title { color: #ccc; font-size: 1.05rem; margin: 0 0 0.9rem; }
.more-skills { margin-top: 1.4rem; }
.more-sum {
  cursor: pointer;
  list-style: none;
  color: var(--muted);
}
.more-sum::-webkit-details-marker { display: none; }
.more-skills[open] .more-sum { color: #ccc; }

.pack-more {
  margin-top: 0.85rem;
  border: 1px dashed var(--border);
  border-radius: 10px;
  padding: 0.55rem 0.75rem;
}
.pack-more > summary {
  cursor: pointer;
  color: var(--cyan);
  font-weight: 700;
  font-size: 0.9rem;
}
.pack-more-body { margin-top: 0.65rem; }
.grid { display: grid; gap: 0.9rem; }
@media (min-width: 640px) { .grid.two { grid-template-columns: 1fr 1fr; } }

.card {
  display: block;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.1rem 1.15rem;
  color: inherit;
  position: relative;
  overflow: hidden;
}
a.card:hover { border-color: #444; }
.card::before {
  content: "";
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 4px;
  background: var(--stripe, var(--accent));
}
.card:nth-child(2) { --stripe: var(--cyan); }
.card:nth-child(3) { --stripe: var(--pink); }
.card h2 { font-size: 1.1rem; margin: 0.35rem 0; }
.card p { margin: 0; color: var(--muted); font-size: 0.92rem; }
.card .foot {
  margin-top: 0.85rem;
  display: flex;
  justify-content: space-between;
  color: #777;
  font-size: 0.8rem;
}

.badge {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 700;
  padding: 0.18rem 0.5rem;
  border-radius: 999px;
  background: rgba(245, 197, 24, 0.15);
  color: var(--accent);
}
.badge.cyan { background: rgba(61,224,255,.14); color: var(--cyan); }
.badge.pink { background: rgba(255,92,171,.14); color: var(--pink); }
.badge.mint { background: rgba(93,255,176,.14); color: var(--mint); }
.badge.gray { background: #222; color: #888; }

.goal-list { list-style: none; padding: 0; margin: 1rem 0 0; }
.goal-list li { margin: 0.55rem 0; }
.goal-list a {
  display: flex;
  gap: 0.75rem;
  align-items: center;
  padding: 0.9rem 1rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--card);
  color: inherit;
}
.goal-list a:hover { border-color: #444; }
.goal-list .num {
  color: var(--accent);
  font-weight: 800;
  min-width: 2rem;
}
.goal-list .meta { font-size: 0.82rem; color: var(--muted); margin-top: 0.2rem; }
.goal-list .right { margin-left: auto; color: var(--mint); font-size: 0.85rem; font-weight: 700; }

.section {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem 1.05rem;
  margin: 1rem 0;
}
.section.example { border-left: 4px solid var(--cyan); }
.section.practice { border-left: 4px solid var(--accent); }

.steps { list-style: none; padding: 0; margin: 0.6rem 0 0; }
.steps li {
  display: grid;
  grid-template-columns: 2rem 1fr;
  gap: 0.6rem;
  padding: 0.65rem 0;
  border-bottom: 1px solid var(--border);
}
.steps li:last-child { border-bottom: 0; }
.steps .n {
  width: 1.65rem; height: 1.65rem;
  border-radius: 999px;
  display: grid; place-items: center;
  background: rgba(61,224,255,.15);
  color: var(--cyan);
  font-weight: 800;
  font-size: 0.85rem;
}
.steps strong { display: block; }
.steps span { color: var(--muted); font-size: 0.92rem; }

.tip {
  margin-top: 0.85rem;
  padding: 0.75rem 0.9rem;
  border-radius: 10px;
  border: 1px solid rgba(245,197,24,.4);
  background: rgba(245,197,24,.08);
  color: #f0e6c2;
  font-size: 0.92rem;
}

.choices { display: grid; gap: 0.5rem; margin: 0.75rem 0; }
.choices button {
  appearance: none;
  text-align: left;
  width: 100%;
  border: 1px solid var(--border);
  background: #0d0d0d;
  color: var(--ink);
  font: inherit;
  padding: 0.85rem 1rem;
  border-radius: 10px;
  cursor: pointer;
}
.choices button:hover { border-color: #555; }
.choices button.ok { border-color: var(--mint); background: rgba(93,255,176,.1); }
.choices button.bad { border-color: var(--bad); background: rgba(255,92,106,.1); }

.field {
  width: 100%;
  min-height: 5.5rem;
  background: #0d0d0d;
  border: 1px solid var(--border);
  border-radius: 10px;
  color: var(--ink);
  font: inherit;
  padding: 0.85rem 1rem;
  resize: vertical;
}
.field:focus { outline: none; border-color: var(--cyan); }

.fb {
  margin-top: 0.75rem;
  padding: 0.8rem 0.95rem;
  border-radius: 10px;
  border: 1px solid var(--border);
  color: #ddd;
  font-size: 0.95rem;
}
.fb.ok { border-color: rgba(93,255,176,.4); background: rgba(93,255,176,.08); color: #d9ffe9; }
.fb.bad { border-color: rgba(255,92,106,.4); background: rgba(255,92,106,.08); }

.actions { display: grid; gap: 0.55rem; margin-top: 1rem; }
@media (min-width: 520px) { .actions.two { grid-template-columns: 1fr 1fr; } }

.btn {
  appearance: none;
  border: none;
  border-radius: var(--radius);
  font: inherit;
  font-weight: 800;
  padding: 0.85rem 1rem;
  cursor: pointer;
}
.btn.primary { background: var(--accent); color: var(--accent-ink); }
.btn.ghost { background: transparent; color: var(--ink); border: 1px solid var(--border); }
.btn:disabled { opacity: 0.5; cursor: default; }

.progress {
  height: 5px;
  background: #2a2a2a;
  border-radius: 99px;
  margin-top: 0.8rem;
  overflow: hidden;
}
.progress > span {
  display: block;
  height: 100%;
  width: 0;
  background: var(--stripe, var(--accent));
  border-radius: 99px;
}

.empty {
  color: var(--muted);
  border: 1px dashed var(--border);
  border-radius: var(--radius);
  padding: 1.2rem;
  text-align: center;
}

.pack-block { margin: 1rem 0 0; }
.pack-block h3 {
  font-size: 0.82rem;
  font-weight: 800;
  letter-spacing: 0.06em;
  color: var(--cyan);
  margin: 0 0 0.45rem;
  text-transform: none;
}
.pack-block p { color: #d8d8d8; }
.scene {
  border: 1px solid var(--border);
  background: #101010;
  border-radius: 12px;
  padding: 0.85rem 0.95rem;
  margin: 0.55rem 0;
}
.scene h4 { margin: 0 0 0.4rem; font-size: 0.98rem; }
.pair { display: grid; gap: 0.45rem; margin-top: 0.45rem; }
.pair .good, .pair .bad {
  border-radius: 10px;
  padding: 0.55rem 0.7rem;
  font-size: 0.9rem;
}
.pair .good { background: rgba(93,255,176,.08); border: 1px solid rgba(93,255,176,.28); }
.pair .bad { background: rgba(255,92,106,.08); border: 1px solid rgba(255,92,106,.28); }
.pair .lab { font-size: 0.72rem; font-weight: 800; margin-bottom: 0.2rem; }
.pair .good .lab { color: var(--mint); }
.pair .bad .lab { color: #ff8a96; }
.mistake { color: #cfcfcf; font-size: 0.92rem; margin: 0.35rem 0; }
.mistake b { color: var(--orange); }
.source { font-size: 0.85rem; color: var(--muted); margin-top: 0.85rem; }
.source a { color: var(--cyan); }

.task-tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 0.35rem;
}

.sync-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  align-items: center;
}
.sync-code {
  font-family: ui-monospace, Consolas, monospace;
  font-size: 0.92rem;
  font-weight: 800;
  letter-spacing: 0.05em;
  color: var(--cyan);
  background: #0d0d0d;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.4rem 0.55rem;
  flex: 1;
  min-width: 8rem;
}
.sync-input {
  flex: 1;
  min-width: 8rem;
  background: #0d0d0d;
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--ink);
  font: inherit;
  font-size: 0.9rem;
  padding: 0.4rem 0.55rem;
}
.sync-input:focus { outline: none; border-color: var(--cyan); }
.sync-status {
  margin: 0.45rem 0 0;
  font-size: 0.8rem;
  color: var(--muted);
}
.sync-status.ok { color: var(--mint); }
.sync-status.bad { color: var(--bad); }
.btn.sm {
  padding: 0.55rem 0.85rem;
  font-size: 0.9rem;
  border-radius: 10px;
}

.diagram {
  margin: 0.75rem 0;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: #0c0c0c;
  overflow: hidden;
}
.diagram figcaption {
  padding: 0.55rem 0.85rem;
  font-size: 0.82rem;
  color: var(--muted);
  border-top: 1px solid var(--border);
}
.diagram img, .diagram svg {
  display: block;
  width: 100%;
  height: auto;
  max-height: 360px;
}
.diagram-wrap {
  padding: 0.55rem 0.45rem;
  background: linear-gradient(180deg, #14120e, #0c0c0c);
}
.diagram-wrap svg {
  border-radius: 8px;
}
.link-list {
  list-style: none;
  padding: 0;
  margin: 0.55rem 0 0;
  display: grid;
  gap: 0.45rem;
}
.link-list a {
  display: block;
  padding: 0.7rem 0.85rem;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: #101010;
  color: var(--cyan);
  font-weight: 700;
  font-size: 0.92rem;
}
.link-list a:hover { border-color: #555; }
.link-list .note {
  display: block;
  margin-top: 0.25rem;
  color: var(--muted);
  font-weight: 500;
  font-size: 0.82rem;
}