:root {
  --bg: #0f1115;
  --bg-2: #161922;
  --bg-3: #1d212c;
  --line: #2a3040;
  --fg: #e6e9f0;
  --fg-dim: #98a1b3;
  --fg-mute: #6b7488;
  --accent: #4ade80;
  --accent-dim: #22c55e;
  --blue: #60a5fa;
  --amber: #fbbf24;
  --red: #f87171;
  --purple: #c084fc;
  --radius: 12px;
  --mono: 'SF Mono', 'JetBrains Mono', Menlo, Consolas, 'Courier New', monospace;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB',
    'Microsoft YaHei', sans-serif;
  font-size: 15px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

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

/* ── 顶栏 ── */
.topbar {
  display: flex;
  align-items: center;
  gap: 28px;
  padding: 0 24px;
  height: 58px;
  background: rgba(15, 17, 21, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
  position: sticky;
  top: 0;
  z-index: 100;
}

.brand { display: flex; align-items: center; gap: 10px; color: var(--fg); font-weight: 600; }
.brand-mark {
  width: 28px; height: 28px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--accent), #0ea5e9);
  color: #06131d;
  display: grid; place-items: center;
  font-size: 12px; font-weight: 800;
  letter-spacing: -0.5px;
}
.brand-text { font-size: 15px; }

.topnav { display: flex; gap: 4px; margin-left: auto; }
.topnav a {
  color: var(--fg-dim);
  padding: 7px 14px;
  border-radius: 8px;
  font-size: 14px;
  transition: all .16s;
  display: flex; align-items: center; gap: 7px;
}
.topnav a:hover { color: var(--fg); background: var(--bg-3); }
.topnav a.on { color: var(--accent); background: rgba(74, 222, 128, 0.1); }

.who { display: flex; gap: 8px; }
.who-input {
  width: 96px;
  background: var(--bg-3);
  border: 1px solid var(--line);
  color: var(--fg);
  border-radius: 8px;
  padding: 6px 10px;
  font-size: 13px;
  font-family: inherit;
}
.who-input:focus { outline: none; border-color: var(--accent-dim); }
.who-input::placeholder { color: var(--fg-mute); }

/* ── 通用容器 ── */
.wrap { max-width: 1160px; margin: 0 auto; padding: 40px 24px 80px; }

.hero { padding: 8px 0 32px; }
.hero h1 {
  font-size: 30px;
  margin: 0 0 8px;
  letter-spacing: -0.5px;
  background: linear-gradient(100deg, #fff 20%, var(--accent) 90%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}
.hero p { margin: 0; color: var(--fg-dim); font-size: 15px; }
.hero.compact { padding-bottom: 20px; }
.hero-note {
  margin-top: 18px;
  display: inline-flex;
  gap: 9px;
  align-items: flex-start;
  padding: 10px 14px;
  background: rgba(96, 165, 250, 0.08);
  border: 1px solid rgba(96, 165, 250, 0.22);
  border-radius: 10px;
  color: #a9c9f5;
  font-size: 13.5px;
  max-width: 760px;
}
.hero-note i { margin-top: 4px; }

/* ── 题目卡片 ── */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(292px, 1fr));
  gap: 16px;
}
.card {
  display: flex;
  flex-direction: column;
  gap: 10px;
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px;
  color: inherit;
  transition: all .18s;
  position: relative;
  overflow: hidden;
}
.card::before {
  content: '';
  position: absolute;
  inset: 0 0 auto 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--accent), transparent);
  opacity: 0;
  transition: opacity .18s;
}
.card:hover { border-color: #3a4457; transform: translateY(-2px); background: var(--bg-3); }
.card:hover::before { opacity: 1; }
.card-top { display: flex; gap: 8px; align-items: center; }
.card h3 { margin: 2px 0 0; font-size: 16px; font-weight: 600; line-height: 1.4; }
.card-meta { margin: 0; color: var(--fg-mute); font-size: 13px; }
.card-go {
  margin-top: auto;
  padding-top: 8px;
  color: var(--accent);
  font-size: 13.5px;
  display: flex; align-items: center; gap: 6px;
}

.lang-pill, .kind-pill {
  font-size: 11.5px;
  padding: 3px 9px;
  border-radius: 999px;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 5px;
}
.lang-java { background: rgba(248, 113, 113, 0.14); color: #fca5a5; }
.lang-c { background: rgba(96, 165, 250, 0.14); color: #93c5fd; }
.lang-python { background: rgba(251, 191, 36, 0.14); color: #fcd34d; }
.kind-pill { background: var(--bg-3); color: var(--fg-dim); border: 1px solid var(--line); }

/* ── 说明区 ── */
.howto { margin-top: 44px; }
.howto h2 { font-size: 17px; margin: 0 0 16px; color: var(--fg-dim); font-weight: 600; }
.steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 12px;
  list-style: none;
  padding: 0;
  margin: 0;
  counter-reset: s;
}
.steps li {
  counter-increment: s;
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 16px 16px 16px 46px;
  position: relative;
  font-size: 13.5px;
  color: var(--fg-dim);
}
.steps li::before {
  content: counter(s);
  position: absolute;
  left: 14px; top: 15px;
  width: 20px; height: 20px;
  border-radius: 6px;
  background: rgba(74, 222, 128, 0.14);
  color: var(--accent);
  font-size: 12px;
  font-weight: 700;
  display: grid; place-items: center;
}
.steps li b { display: block; color: var(--fg); margin-bottom: 3px; font-size: 14px; }

/* ── 做题页布局 ── */
.solve {
  display: grid;
  grid-template-columns: minmax(340px, 42%) 1fr;
  height: calc(100vh - 58px);
  overflow: hidden;
}
.stmt {
  overflow-y: auto;
  padding: 26px 30px 60px;
  border-right: 1px solid var(--line);
  background: var(--bg-2);
}
.back {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: 13px; color: var(--fg-mute); margin-bottom: 16px;
}
.back:hover { color: var(--fg); }
.stmt h1 { font-size: 21px; margin: 0 0 12px; line-height: 1.35; }
.badges { display: flex; gap: 8px; margin-bottom: 22px; }

.md { font-size: 14px; color: #c3cad9; }
.md h3 { font-size: 15px; color: var(--fg); margin: 22px 0 8px; }
.md h4 { font-size: 14px; color: var(--fg); margin: 18px 0 6px; }
.md p { margin: 9px 0; }
.md ul, .md ol { margin: 9px 0; padding-left: 20px; }
.md li { margin: 4px 0; }
.md code {
  font-family: var(--mono);
  background: var(--bg-3);
  padding: 1.5px 5px;
  border-radius: 4px;
  font-size: 12.5px;
  color: #a5d6ff;
}
.md pre {
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 13px 15px;
  overflow-x: auto;
  font-size: 12.5px;
  line-height: 1.6;
}
.md pre code { background: none; padding: 0; color: #cdd6e6; }
.md table { width: 100%; border-collapse: collapse; font-size: 13px; margin: 12px 0; }
.md th, .md td { border: 1px solid var(--line); padding: 7px 10px; text-align: left; }
.md th { background: var(--bg-3); color: var(--fg); font-weight: 600; }
.md strong { color: var(--fg); }
.md hr { border: none; border-top: 1px solid var(--line); margin: 20px 0; }

/* ── 工作区 ── */
.work { display: flex; flex-direction: column; overflow: hidden; background: var(--bg); }
.work-head {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 18px;
  border-bottom: 1px solid var(--line);
  background: var(--bg-2);
}
.file-name {
  font-family: var(--mono);
  font-size: 12.5px;
  color: var(--fg-dim);
  padding: 4px 10px;
  background: var(--bg);
  border-radius: 6px;
}
.work-actions { margin-left: auto; display: flex; gap: 8px; }

.btn {
  font-family: inherit;
  font-size: 13.5px;
  padding: 7px 16px;
  border-radius: 8px;
  border: 1px solid var(--line);
  background: var(--bg-3);
  color: var(--fg);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 7px;
  transition: all .15s;
  font-weight: 500;
}
.btn:hover { background: #252a36; }
.btn.primary {
  background: var(--accent-dim);
  border-color: var(--accent-dim);
  color: #04120a;
  font-weight: 600;
}
.btn.primary:hover { background: var(--accent); }
.btn:disabled { opacity: .55; cursor: not-allowed; }
.btn.ghost { background: transparent; }

.editor-wrap { flex: 1; min-height: 0; position: relative; }
#editor { position: absolute; inset: 0; }
.editor-wrap.ro { flex: 0 0 auto; height: 240px; border-bottom: 1px solid var(--line); }
.head-note { font-size: 12.5px; color: var(--fg-mute); }

/* ── 填空作答区 ── */
.blank-form {
  padding: 14px 20px 20px;
  background: var(--bg-2);
  border-bottom: 1px solid var(--line);
  max-height: 300px;
  overflow-y: auto;
  flex-shrink: 0;
}
.blank-form .section-title { margin-top: 0; }
.bf-row { display: flex; gap: 12px; align-items: flex-start; padding: 7px 0; }
.bf-label {
  width: 24px; height: 24px; flex-shrink: 0;
  border-radius: 7px;
  background: rgba(74, 222, 128, 0.12);
  color: var(--accent);
  display: grid; place-items: center;
  font-size: 13px; font-weight: 700;
  margin-top: 3px;
}
.bf-main { flex: 1; min-width: 0; }
.bf-input {
  width: 100%;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--fg);
  font-family: var(--mono);
  font-size: 13px;
  padding: 8px 12px;
  transition: border-color .15s;
}
.bf-input:focus { outline: none; border-color: var(--accent-dim); box-shadow: 0 0 0 3px rgba(74,222,128,.09); }
.bf-input::placeholder { color: #5a6478; font-family: inherit; font-size: 12.5px; }
.bf-context {
  font-family: var(--mono);
  font-size: 11.5px;
  color: #5f6a80;
  margin-top: 4px;
  white-space: pre;
  overflow-x: auto;
}

/* ── 结果面板 ── */
.result {
  border-top: 1px solid var(--line);
  background: var(--bg-2);
  max-height: 46%;
  overflow-y: auto;
  padding: 18px 20px 26px;
  flex-shrink: 0;
}
.result-idle {
  display: flex; align-items: center; gap: 12px;
  color: var(--fg-mute); font-size: 13.5px; padding: 12px 0;
}
.result-idle i { font-size: 18px; }

.verdict-head { display: flex; align-items: center; gap: 14px; margin-bottom: 16px; flex-wrap: wrap; }
.verdict-badge {
  font-size: 13px; font-weight: 700; padding: 5px 13px; border-radius: 8px;
  display: inline-flex; align-items: center; gap: 7px;
}
.v-accepted { background: rgba(74,222,128,.15); color: var(--accent); }
.v-partial { background: rgba(251,191,36,.15); color: var(--amber); }
.v-compile_error, .v-runtime_error { background: rgba(248,113,113,.15); color: var(--red); }
.v-failed { background: rgba(148,163,184,.15); color: #94a3b8; }

.score-box { display: flex; align-items: baseline; gap: 4px; }
.score-num { font-size: 26px; font-weight: 700; letter-spacing: -1px; }
.score-max { font-size: 13px; color: var(--fg-mute); }
.meta-line { margin-left: auto; font-size: 12.5px; color: var(--fg-mute); display: flex; gap: 14px; }

.bar-row { display: flex; gap: 8px; margin-bottom: 16px; flex-wrap: wrap; }
.bar-item {
  flex: 1; min-width: 120px;
  background: var(--bg-3);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 9px 12px;
}
.bar-item .bi-label { font-size: 11.5px; color: var(--fg-mute); }
.bar-item .bi-val { font-size: 15px; font-weight: 600; margin-top: 1px; }
.bar-item .bi-detail { font-size: 11.5px; color: var(--fg-mute); margin-top: 2px; }
.track { height: 3px; background: #2a3040; border-radius: 2px; margin-top: 7px; overflow: hidden; }
.track > i { display: block; height: 100%; background: var(--accent); border-radius: 2px; transition: width .4s; }

.compile-box {
  background: #1a1416;
  border: 1px solid rgba(248,113,113,.3);
  border-radius: 10px;
  padding: 13px 15px;
  font-family: var(--mono);
  font-size: 12.5px;
  color: #fca5a5;
  white-space: pre-wrap;
  word-break: break-word;
  margin-bottom: 16px;
  max-height: 240px;
  overflow-y: auto;
}

.case-list { display: flex; flex-direction: column; gap: 8px; }
.case {
  border: 1px solid var(--line);
  border-radius: 9px;
  overflow: hidden;
  background: var(--bg-3);
}
.case-head {
  display: flex; align-items: center; gap: 10px;
  padding: 9px 13px; font-size: 13px; cursor: pointer;
}
.case-head .ci { width: 16px; }
.case-pass { color: var(--accent); }
.case-fail { color: var(--red); }
.case-error { color: var(--amber); }
.case-title { flex: 1; }
.case-time { color: var(--fg-mute); font-size: 11.5px; font-family: var(--mono); }
.case-body { padding: 0 13px 12px; font-size: 12.5px; display: none; }
.case.open .case-body { display: block; }
.case-body .row { display: grid; grid-template-columns: 74px 1fr; gap: 10px; padding: 3px 0; }
.case-body .row span:first-child { color: var(--fg-mute); }
.case-body pre {
  margin: 3px 0; background: var(--bg); padding: 8px 10px; border-radius: 6px;
  font-family: var(--mono); font-size: 12px; white-space: pre-wrap; word-break: break-word;
  color: #cdd6e6; max-height: 150px; overflow-y: auto;
}
.case-msg {
  margin-top: 8px; padding: 8px 11px; border-radius: 7px;
  background: rgba(251,191,36,.09); border-left: 2px solid var(--amber);
  color: #fcd34d; font-size: 12.5px; white-space: pre-wrap;
}

/* 空位判定 */
.blank-grid { display: grid; gap: 8px; margin-bottom: 16px; }
.blank-row {
  display: flex; align-items: flex-start; gap: 11px;
  padding: 10px 13px;
  border: 1px solid var(--line);
  border-radius: 9px;
  background: var(--bg-3);
  font-size: 13px;
}
.blank-id {
  width: 22px; height: 22px; flex-shrink: 0;
  border-radius: 6px; display: grid; place-items: center;
  font-size: 12px; font-weight: 700;
  background: var(--bg); color: var(--fg-mute);
}
.b-exact .blank-id { background: rgba(74,222,128,.16); color: var(--accent); }
.b-equiv .blank-id { background: rgba(96,165,250,.16); color: var(--blue); }
.b-wrong .blank-id { background: rgba(248,113,113,.16); color: var(--red); }
.b-empty .blank-id { background: rgba(148,163,184,.14); color: #94a3b8; }
.blank-main { flex: 1; min-width: 0; }
.blank-intent { color: var(--fg-dim); font-size: 12.5px; }
.blank-code {
  font-family: var(--mono); font-size: 12.5px; margin-top: 3px;
  color: #a5d6ff; word-break: break-all;
}
.blank-hint {
  margin-top: 6px; font-size: 12.5px; color: #fcd34d;
  padding: 5px 9px; background: rgba(251,191,36,.08); border-radius: 6px;
}
.blank-tag { font-size: 11px; padding: 2px 7px; border-radius: 5px; flex-shrink: 0; }
.t-exact { background: rgba(74,222,128,.14); color: var(--accent); }
.t-equiv { background: rgba(96,165,250,.14); color: var(--blue); }
.t-wrong { background: rgba(248,113,113,.14); color: var(--red); }
.t-empty { background: rgba(148,163,184,.14); color: #94a3b8; }

.section-title {
  font-size: 12px; text-transform: uppercase; letter-spacing: .8px;
  color: var(--fg-mute); margin: 18px 0 9px; font-weight: 600;
  display: flex; align-items: center; gap: 8px;
}
.section-title::after { content: ''; flex: 1; height: 1px; background: var(--line); }

.err-banner {
  background: rgba(248,113,113,.1);
  border: 1px solid rgba(248,113,113,.28);
  color: #fca5a5;
  padding: 11px 15px;
  border-radius: 9px;
  font-size: 13px;
  margin-bottom: 14px;
}

/* ── 教师看板 ── */
.teacher-root { min-height: 200px; }
.loading { color: var(--fg-mute); padding: 40px 0; text-align: center; }

.t-overview {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 12px;
  margin-bottom: 34px;
}
.t-card {
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 16px;
  cursor: pointer;
  transition: all .16s;
}
.t-card:hover { border-color: #3a4457; background: var(--bg-3); }
.t-card.on { border-color: var(--accent-dim); background: rgba(74,222,128,.06); }
.t-card h4 { margin: 0 0 10px; font-size: 14px; font-weight: 600; line-height: 1.4; }
.t-stats { display: flex; gap: 18px; font-size: 12px; color: var(--fg-mute); }
.t-stats b { display: block; color: var(--fg); font-size: 17px; font-weight: 700; }

.detail-head {
  display: flex; align-items: center; gap: 14px; flex-wrap: wrap;
  margin-bottom: 22px; padding-bottom: 16px; border-bottom: 1px solid var(--line);
}
.detail-head h2 { margin: 0; font-size: 18px; }
.kpis { display: flex; gap: 24px; margin-left: auto; }
.kpi { text-align: right; }
.kpi b { display: block; font-size: 20px; font-weight: 700; }
.kpi span { font-size: 11.5px; color: var(--fg-mute); }

.heat { display: flex; flex-direction: column; gap: 10px; }
.heat-row {
  display: grid;
  grid-template-columns: 40px 1fr 190px;
  gap: 14px;
  align-items: center;
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 13px 16px;
}
.heat-id {
  width: 26px; height: 26px; border-radius: 7px;
  background: var(--bg-3); color: var(--fg);
  display: grid; place-items: center; font-weight: 700; font-size: 13px;
}
.heat-mid { min-width: 0; }
.heat-intent { font-size: 13px; color: var(--fg); margin-bottom: 7px; }
.heat-bar { display: flex; height: 22px; border-radius: 5px; overflow: hidden; background: var(--bg); }
.heat-bar > div { transition: width .4s; }
.hb-exact { background: var(--accent-dim); }
.hb-equiv { background: #3b82f6; }
.hb-wrong { background: #ef4444; }
.hb-empty { background: #475569; }
.heat-legend { display: flex; gap: 12px; font-size: 11px; color: var(--fg-mute); margin-top: 6px; flex-wrap: wrap; }
.heat-legend i { display: inline-block; width: 8px; height: 8px; border-radius: 2px; margin-right: 4px; }
.heat-pct { text-align: right; }
.heat-pct .p { font-size: 20px; font-weight: 700; }
.heat-pct .l { font-size: 11px; color: var(--fg-mute); }

.wrong-list { margin-top: 8px; font-size: 12px; }
.wrong-list .wi {
  display: flex; gap: 8px; align-items: baseline;
  padding: 3px 0; color: var(--fg-dim);
}
.wrong-list code {
  font-family: var(--mono); font-size: 11.5px; color: #fca5a5;
  background: rgba(248,113,113,.08); padding: 1px 6px; border-radius: 4px;
}
.wrong-list .cnt { margin-left: auto; color: var(--fg-mute); font-size: 11px; }

.recent-table { width: 100%; border-collapse: collapse; font-size: 13px; margin-top: 8px; }
.recent-table th {
  text-align: left; padding: 8px 10px; color: var(--fg-mute);
  font-weight: 500; font-size: 12px; border-bottom: 1px solid var(--line);
}
.recent-table td { padding: 8px 10px; border-bottom: 1px solid #222836; }
.recent-table tr:hover td { background: var(--bg-2); }
.mono { font-family: var(--mono); font-size: 12px; }

.empty-state {
  text-align: center; color: var(--fg-mute); padding: 60px 20px; font-size: 14px;
}
.empty-state i { font-size: 32px; display: block; margin-bottom: 14px; opacity: .4; }

@media (max-width: 900px) {
  .solve { grid-template-columns: 1fr; height: auto; overflow: visible; }
  .stmt { border-right: none; border-bottom: 1px solid var(--line); max-height: 45vh; }
  .work { height: 80vh; }
  .brand-text { display: none; }
  .topbar { gap: 12px; padding: 0 14px; }
  .who-input { width: 74px; }
  .heat-row { grid-template-columns: 32px 1fr; }
  .heat-pct { grid-column: 2; text-align: left; }
}

.blank-deco {
  background: rgba(74, 222, 128, 0.16);
  border-bottom: 2px solid rgba(74, 222, 128, 0.5);
  border-radius: 2px;
}