/* ============ 杜鸣OJ 设计系统 ============ */
:root {
  --primary: #4f46e5;
  --primary-dark: #4338ca;
  --primary-light: #eef2ff;
  --bg: #f4f5fb;
  --card: #ffffff;
  --text: #1f2937;
  --text-2: #6b7280;
  --text-3: #9ca3af;
  --border: #e5e7eb;
  --ac: #16a34a;
  --wa: #dc2626;
  --tle: #ea580c;
  --re: #7c3aed;
  --ce: #2563eb;
  --pending: #9ca3af;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(17, 24, 39, .06), 0 4px 14px rgba(17, 24, 39, .05);
  --mono: "JetBrains Mono", "Cascadia Code", Consolas, "Courier New", monospace;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { -webkit-font-smoothing: antialiased; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg); color: var(--text); font-size: 15px; line-height: 1.65;
}
a { color: var(--primary); text-decoration: none; }
a:hover { color: var(--primary-dark); }
button { font-family: inherit; cursor: pointer; }

/* 键盘可达性：焦点可见（鼠标点击不显示轮廓） */
:focus-visible { outline: 2px solid var(--primary); outline-offset: 2px; }

/* ============ 顶栏 ============ */
.topbar {
  position: sticky; top: 0; z-index: 100;
  display: flex; align-items: center; gap: 28px;
  height: 60px; padding: 0 28px;
  background: rgba(255,255,255,.92); backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.brand { display: flex; align-items: center; gap: 8px; font-size: 19px; font-weight: 700; color: var(--text); }
.brand:hover { color: var(--text); }
.brand-logo {
  width: 32px; height: 32px;
  border-radius: 8px;
  object-fit: contain;
  background: transparent;
}
.brand-name em { font-style: normal; color: var(--primary); }
.brand-badge {
  font-size: 11px; font-weight: 600; color: var(--primary);
  background: var(--primary-light); padding: 2px 8px; border-radius: 99px;
  border: 1px solid #c7d2fe;
}
.nav { display: flex; gap: 4px; flex: 1; }
.nav a {
  padding: 7px 14px; border-radius: 8px; color: var(--text-2);
  font-weight: 500; transition: all .15s;
}
.nav a:hover { background: var(--bg); color: var(--text); }
.nav a.active { background: var(--primary-light); color: var(--primary); }
.userbox { display: flex; align-items: center; gap: 12px; font-size: 14px; }
.userbox .who { color: var(--text-2); }
.userbox .who b { color: var(--text); }
.role-tag { font-size: 11px; padding: 1px 7px; border-radius: 99px; font-weight: 600; }
.role-student { background: #ecfdf5; color: #059669; }
.role-teacher { background: #fffbeb; color: #d97706; }
.role-admin { background: #fef2f2; color: #dc2626; }

/* ============ 布局 ============ */
.view { max-width: 1240px; margin: 0 auto; padding: 28px 24px 60px; }
.page-head { display: flex; align-items: baseline; gap: 14px; margin-bottom: 20px; flex-wrap: wrap; }
.page-head h1 { font-size: 24px; font-weight: 700; }
.page-head .sub { color: var(--text-2); font-size: 14px; }

.card {
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--radius); box-shadow: var(--shadow);
}

/* ============ 按钮 ============ */
.btn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 8px 18px; border-radius: 9px; border: 1px solid transparent;
  font-size: 14px; font-weight: 600; transition: all .15s;
  background: var(--primary); color: #fff;
}
.btn:hover { background: var(--primary-dark); color: #fff; }
.btn.ghost { background: #fff; color: var(--text); border-color: var(--border); }
.btn.ghost:hover { border-color: var(--primary); color: var(--primary); }
.btn.small { padding: 4px 12px; font-size: 13px; border-radius: 7px; }
.btn:disabled { opacity: .55; cursor: not-allowed; }
.btn.danger { background: var(--wa); }
.btn-row { display: flex; gap: 10px; flex-wrap: wrap; }

/* ============ 表单 ============ */
.field { margin-bottom: 16px; }
.field label { display: block; font-size: 13px; font-weight: 600; color: var(--text-2); margin-bottom: 6px; }
.input, .select, textarea.input {
  width: 100%; padding: 9px 13px; border: 1px solid var(--border);
  border-radius: 9px; font-size: 14px; font-family: inherit;
  background: #fff; transition: border .15s, box-shadow .15s;
}
.input:focus, .select:focus, textarea.input:focus {
  outline: none; border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(79, 70, 229, .12);
}
textarea.input { resize: vertical; min-height: 90px; }

/* ============ 状态徽章 ============ */
.badge {
  display: inline-flex; align-items: center; gap: 5px;
  font-size: 12px; font-weight: 700; padding: 2px 10px; border-radius: 99px;
  font-family: var(--mono);
}
.badge::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: currentColor; }
.b-AC { color: var(--ac); background: #f0fdf4; }
.b-WA { color: var(--wa); background: #fef2f2; }
.b-TLE { color: var(--tle); background: #fff7ed; }
.b-RE { color: var(--re); background: #f5f3ff; }
.b-CE { color: var(--ce); background: #eff6ff; }
.b-MLE { color: var(--re); background: #f5f3ff; }
.b-SE { color: var(--text-2); background: #f3f4f6; }
.b-pending, .b-judging { color: var(--pending); background: #f3f4f6; }
.b-pending::before, .b-judging::before { animation: pulse 1s infinite; }
@keyframes pulse { 50% { opacity: .25; } }

.diff { display: inline-block; min-width: 34px; text-align: center; font-size: 12px; font-weight: 700;
  padding: 1px 8px; border-radius: 6px; font-family: var(--mono); }
.d1 { background: #ecfdf5; color: #059669; }
.d2 { background: #eff6ff; color: #2563eb; }
.d3 { background: #fffbeb; color: #d97706; }
.d4 { background: #fff7ed; color: #ea580c; }
.d5 { background: #fef2f2; color: #dc2626; }

/* ============ 题库列表 ============ */
.filters { display: flex; gap: 10px; margin-bottom: 18px; flex-wrap: wrap; align-items: center; }
.filters .input { width: 220px; }
.filters .select { width: 130px; }
.tag-chip {
  font-size: 12px; padding: 3px 11px; border-radius: 99px;
  background: #fff; border: 1px solid var(--border); color: var(--text-2); cursor: pointer;
}
.tag-chip:hover, .tag-chip.on { border-color: var(--primary); color: var(--primary); background: var(--primary-light); }
.tag-chip .tag-n { margin-left: 4px; font-size: 10.5px; color: var(--text-3); }

/* 题库分页器 */
.pager {
  display: flex; gap: 10px; align-items: center; justify-content: center;
  padding: 14px 16px; border-top: 1px solid var(--border); flex-wrap: wrap;
}
.pager-info { font-size: 13px; color: var(--text-2); }
.pager .btn[disabled] { opacity: .4; cursor: not-allowed; }
.pager .pg-jump { width: 72px; text-align: center; }

/* 题库分区枢纽 */
.hub-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 16px; margin-bottom: 20px;
}
.hub-card {
  display: block; background: #fff; border: 1px solid var(--border);
  border-radius: 14px; padding: 20px 22px; text-decoration: none;
  color: var(--text); transition: transform .15s, border-color .15s, box-shadow .15s;
}
.hub-card:hover {
  transform: translateY(-3px); border-color: var(--primary);
  box-shadow: 0 6px 18px rgba(20, 40, 80, .08); color: var(--text);
}
.hub-card-h { display: flex; align-items: baseline; justify-content: space-between; gap: 10px; margin-bottom: 8px; }
.hub-card-h h3 { margin: 0; font-size: 17px; }
.hub-count { font-size: 13px; font-weight: 700; color: var(--primary); white-space: nowrap; }
.hub-card p { margin: 0 0 12px; font-size: 13px; color: var(--text-2); line-height: 1.6; }
.hub-go { font-size: 13px; color: var(--primary); font-weight: 600; }

/* 题库分区 Tab（常驻列表顶部，替代枢纽中转页） */
.prob-tabs { display: flex; gap: 8px; margin-bottom: 14px; flex-wrap: wrap; }
.prob-tab {
  display: inline-flex; align-items: baseline; gap: 6px;
  padding: 7px 14px; border-radius: 8px; font-weight: 500; font-size: 14px;
  background: #fff; border: 1px solid var(--border); color: var(--text-2);
  transition: all .15s;
}
.prob-tab:hover { border-color: var(--primary); color: var(--primary); }
.prob-tab small { font-size: 12px; color: var(--text-3); font-weight: 400; }
.prob-tab.on { background: var(--primary-light); border-color: var(--primary); color: var(--primary); }
.prob-tab.on small { color: var(--primary); }

/* 题目页 上一题/下一题 导航条 */
.prob-sibnav { display: flex; align-items: center; justify-content: space-between; gap: 10px; margin: 12px 0 2px; }

.prob-table { width: 100%; border-collapse: collapse; }
.prob-table th {
  text-align: left; font-size: 12px; color: var(--text-3); font-weight: 600;
  padding: 10px 14px; border-bottom: 1px solid var(--border); text-transform: uppercase; letter-spacing: .04em;
}
.prob-table td { padding: 13px 14px; border-bottom: 1px solid #f3f4f6; vertical-align: middle; }
.prob-table tr:last-child td { border-bottom: none; }
.prob-table tbody tr { transition: background .12s; }
.prob-table tbody tr:hover { background: #fafafe; }
.prob-code { font-family: var(--mono); font-weight: 700; color: var(--text-2); font-size: 13px; }
.prob-title { font-weight: 600; }
.prob-title a { color: var(--text); }
.prob-title a:hover { color: var(--primary); }
.my-status { font-size: 12px; font-weight: 700; }
.ms-AC { color: var(--ac); }
.ms-tried { color: var(--tle); }
.ms-new { color: var(--text-3); }
.tags-cell { display: flex; gap: 5px; flex-wrap: wrap; }
.mini-tag { font-size: 11px; color: var(--text-3); background: #f3f4f6; padding: 1px 8px; border-radius: 99px; }

/* ============ 题目详情 ============ */
.prob-layout { display: grid; grid-template-columns: minmax(0, 5fr) minmax(0, 6fr); gap: 20px; align-items: start; }
@media (max-width: 980px) { .prob-layout { grid-template-columns: 1fr; } }

.panel { padding: 20px 22px; }
.panel h3 { font-size: 15px; font-weight: 700; margin-bottom: 12px; display: flex; align-items: center; gap: 8px; }
.md h1, .md h2, .md h3 { margin: 14px 0 8px; line-height: 1.4; }
.md p { margin: 8px 0; }
.md ul, .md ol { margin: 8px 0 8px 22px; }
.md code { font-family: var(--mono); font-size: 13px; background: #f3f4f6; padding: 1px 6px; border-radius: 5px; }
.md pre { background: #1e293b; color: #e2e8f0; padding: 14px 16px; border-radius: 10px; overflow-x: auto; margin: 10px 0; }
.md pre code { background: none; color: inherit; padding: 0; }
.md blockquote { border-left: 3px solid var(--primary); background: var(--primary-light); padding: 8px 14px; border-radius: 0 8px 8px 0; margin: 10px 0; color: var(--text-2); }

.sample-box { border: 1px solid var(--border); border-radius: 10px; overflow: hidden; margin: 10px 0; }
.sample-box .sb-head { background: #f9fafb; padding: 6px 14px; font-size: 12px; font-weight: 700; color: var(--text-2); border-bottom: 1px solid var(--border); }
.sample-box .sb-body { display: grid; grid-template-columns: 1fr 1fr; }
.sample-box .sb-body > div { padding: 10px 14px; font-family: var(--mono); font-size: 13px; white-space: pre-wrap; word-break: break-all; }
.sample-box .sb-body > div + div { border-left: 1px solid var(--border); }
.sample-box .sb-label { font-size: 11px; color: var(--text-3); font-family: inherit; display: block; margin-bottom: 4px; }

/* ============ 编辑器 ============ */
.editor-wrap { border: 1px solid var(--border); border-radius: 10px; overflow: hidden; }
.editor-toolbar {
  display: flex; align-items: center; gap: 10px;
  padding: 8px 12px; background: #f9fafb; border-bottom: 1px solid var(--border);
}
.editor-toolbar .select { width: 120px; padding: 5px 10px; font-size: 13px; }
#monaco { height: 380px; }

/* ============ AI 面板 ============ */
.ai-panel { margin-top: 16px; border: 1px solid #c7d2fe; border-radius: var(--radius); overflow: hidden; background: linear-gradient(180deg, #f5f7ff, #fff); }
.ai-head {
  display: flex; align-items: center; gap: 8px;
  padding: 10px 16px; background: var(--primary-light); border-bottom: 1px solid #c7d2fe;
  font-weight: 700; font-size: 14px; color: var(--primary-dark);
}
.ai-tabs { display: flex; gap: 4px; margin-left: auto; }
.ai-tabs button {
  border: none; background: transparent; padding: 4px 12px; border-radius: 7px;
  font-size: 13px; font-weight: 600; color: var(--text-2);
}
.ai-tabs button.on { background: #fff; color: var(--primary); box-shadow: 0 1px 3px rgba(0,0,0,.08); }
.ai-body { padding: 16px; min-height: 120px; }
.ai-body .placeholder { color: var(--text-3); font-size: 14px; text-align: center; padding: 24px 0; }
.ai-output { font-size: 14px; line-height: 1.7; white-space: pre-wrap; word-break: break-word; }
.ai-output .ai-meta { font-size: 12px; color: var(--text-3); margin-top: 10px; font-family: var(--mono); }
.hint-btns { display: flex; gap: 8px; margin-bottom: 12px; flex-wrap: wrap; }
.hint-btns .btn { background: #fff; color: var(--primary); border: 1px solid #c7d2fe; }
.hint-btns .btn:hover { background: var(--primary); color: #fff; }
.ai-loading { display: inline-flex; align-items: center; gap: 8px; color: var(--text-2); font-size: 14px; }
.ai-loading::before {
  content: ""; width: 14px; height: 14px; border: 2px solid #c7d2fe;
  border-top-color: var(--primary); border-radius: 50%; animation: spin .7s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ============ AI 入口（题目旁/任务旁） ============ */
.btn-ai {
  display: inline-flex; align-items: center; gap: 4px;
  padding: 4px 11px; border-radius: 7px; font-size: 12.5px; font-weight: 600;
  background: var(--primary-light); color: var(--primary);
  border: 1px solid #c7d2fe; transition: all .15s; white-space: nowrap;
}
.btn-ai:hover { background: var(--primary); color: #fff; border-color: var(--primary); }
.btn-ai.small { padding: 2px 9px; font-size: 12px; }
.ai-inline { display: flex; gap: 5px; }
.ai-lock {
  padding: 7px 16px; font-size: 12.5px; color: var(--primary-dark);
  background: rgba(79, 70, 229, .06); border-bottom: 1px solid #e0e7ff;
  display: flex; align-items: center; gap: 6px; flex-wrap: wrap;
}
.ai-lock b { color: var(--primary); font-family: var(--mono); }
.ai-quick-grid { display: flex; gap: 8px; flex-wrap: wrap; }
.ai-quick-chip {
  padding: 6px 14px; border-radius: 9px; font-size: 13px; font-weight: 500;
  background: #fff; border: 1px solid var(--border); color: var(--text-2);
  transition: all .15s;
}
.ai-quick-chip:hover { border-color: var(--primary); color: var(--primary); background: var(--primary-light); }
.ai-quick-chip .mono { font-weight: 700; color: var(--text-3); }
.ai-quick-chip:hover .mono { color: var(--primary); }

/* 聊天 */
.chat-msgs { display: flex; flex-direction: column; gap: 10px; max-height: 300px; overflow-y: auto; }
.chat-msg { max-width: 85%; padding: 9px 14px; border-radius: 12px; font-size: 14px; line-height: 1.6; white-space: pre-wrap; word-break: break-word; }
.chat-msg.user { align-self: flex-end; background: var(--primary); color: #fff; border-bottom-right-radius: 4px; }
.chat-msg.bot { align-self: flex-start; background: #f3f4f6; color: var(--text); border-bottom-left-radius: 4px; }
.chat-input-row { display: flex; gap: 8px; margin-top: 12px; }
.chat-input-row .input { flex: 1; }
/* AI 助教快捷指令 */
.chat-quick { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 10px; }
.chat-chip {
  font-size: 12.5px; padding: 5px 12px; border-radius: 99px; cursor: pointer;
  background: #fff; border: 1px solid var(--border); color: var(--text-2); font-family: inherit;
  transition: all .15s;
}
.chat-chip:hover { border-color: var(--primary); color: var(--primary); background: var(--primary-light); }

/* ============ 错题本 / AI 学习闭环 ============ */
.loop-intro { padding: 14px 20px; }
.loop-steps { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.ls { font-size: 13px; font-weight: 600; color: var(--text-2); display: flex; align-items: center; gap: 6px; }
.ls-n { display: grid; place-items: center; width: 20px; height: 20px; border-radius: 50%;
  background: var(--primary); color: #fff; font-size: 11px; font-weight: 700; }
.ls-arrow { color: var(--text-3); font-weight: 700; }
.mistake-item { padding: 16px 20px; border-bottom: 1px solid #f3f4f6; }
.mistake-item:last-child { border-bottom: none; }
.mi-head { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.mi-count { font-size: 12px; font-weight: 700; color: var(--wa); }
.mi-prog { font-size: 12px; font-weight: 700; color: var(--tle); background: #fff7ed; padding: 1px 9px; border-radius: 99px; }
.mi-kp { display: flex; gap: 5px; flex-wrap: wrap; margin: 7px 0; }
.mi-cause { font-size: 13px; color: var(--text-2); background: #fffbeb; border-left: 3px solid #f59e0b;
  padding: 7px 12px; border-radius: 0 8px 8px 0; margin: 8px 0; }
.mi-cause b { color: #b45309; }
.mi-actions { display: flex; gap: 7px; flex-wrap: wrap; margin-top: 10px; }
.mi-out { margin-top: 10px; }
.mi-variants { font-size: 12px; color: var(--text-3); margin-top: 8px; }
.ai-out-box { background: var(--primary-light); border: 1px solid #c7d2fe; border-radius: 10px;
  padding: 12px 14px; font-size: 13.5px; line-height: 1.7; }
.ai-out-box b { color: var(--primary-dark); }

/* ============ 提交结果 ============ */
.result-bar { display: flex; align-items: center; gap: 14px; padding: 14px 18px; margin-top: 14px; }
.result-bar .big { font-size: 18px; font-weight: 800; font-family: var(--mono); }
.result-bar .meta { color: var(--text-2); font-size: 13px; }
.case-table { width: 100%; border-collapse: collapse; font-size: 13px; margin-top: 10px; }
.case-table th { text-align: left; color: var(--text-3); font-size: 12px; padding: 6px 10px; border-bottom: 1px solid var(--border); }
.case-table td { padding: 7px 10px; border-bottom: 1px solid #f3f4f6; font-family: var(--mono); }
.case-detail { background: #fafafa; padding: 10px 14px; font-family: var(--mono); font-size: 12.5px; white-space: pre-wrap; border-radius: 8px; margin-top: 6px; max-height: 200px; overflow: auto; }

/* ============ 通用表格/列表 ============ */
.list-card { padding: 0; overflow: hidden; }
.empty { text-align: center; color: var(--text-3); padding: 48px 0; font-size: 14px; }

/* ============ 统计 ============ */
.stat-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 14px; margin-bottom: 20px; }
.stat-card { padding: 18px 20px; text-align: center; }
.stat-card .num { font-size: 30px; font-weight: 800; color: var(--primary); font-family: var(--mono); }
.stat-card .lbl { font-size: 13px; color: var(--text-2); margin-top: 2px; }
.bar-row { display: flex; align-items: center; gap: 10px; margin: 7px 0; font-size: 13px; }
.bar-row .bl { width: 60px; color: var(--text-2); text-align: right; flex-shrink: 0; }
.bar-track { flex: 1; height: 16px; background: #f3f4f6; border-radius: 99px; overflow: hidden; }
.bar-fill { height: 100%; background: linear-gradient(90deg, var(--primary), #7c3aed); border-radius: 99px; min-width: 2px; transition: width .5s; }
.bar-row .bv { width: 30px; font-family: var(--mono); color: var(--text-2); }

/* ============ 登录页 ============ */
.auth-wrap { max-width: 400px; margin: 60px auto; }
.auth-card { padding: 32px 30px; }
.auth-card h2 { font-size: 21px; margin-bottom: 4px; }
.auth-card .tip { color: var(--text-2); font-size: 13px; margin-bottom: 22px; }
.auth-switch { text-align: center; margin-top: 16px; font-size: 13px; color: var(--text-2); }

/* ============ Toast ============ */
#toast-wrap { position: fixed; top: 74px; right: 22px; z-index: 999; display: flex; flex-direction: column; gap: 8px; }
.toast {
  padding: 11px 18px; border-radius: 10px; font-size: 14px; font-weight: 500;
  background: #1f2937; color: #fff; box-shadow: 0 8px 24px rgba(0,0,0,.18);
  animation: slidein .25s ease; max-width: 360px;
}
.toast.err { background: var(--wa); }
.toast.ok { background: var(--ac); }
@keyframes slidein { from { transform: translateX(30px); opacity: 0; } }

/* ============ 竞赛 ============ */
.contest-card { padding: 18px 22px; margin-bottom: 14px; display: flex; align-items: center; gap: 18px; flex-wrap: wrap; }
.contest-card .info { flex: 1; min-width: 200px; }
.contest-card .info h3 { font-size: 16px; margin-bottom: 3px; }
.contest-card .info .time { font-size: 13px; color: var(--text-2); font-family: var(--mono); }
.c-status { font-size: 12px; font-weight: 700; padding: 3px 12px; border-radius: 99px; }
.cs-running { background: #fef2f2; color: var(--wa); animation: pulse 1.6s infinite; }
.cs-upcoming { background: #eff6ff; color: var(--ce); }
.cs-ended { background: #f3f4f6; color: var(--text-2); }

/* ============ 讨论 ============ */
.discuss-item { padding: 14px 18px; border-bottom: 1px solid #f3f4f6; }
.discuss-item:last-child { border-bottom: none; }
.discuss-item .who { font-size: 13px; color: var(--text-2); margin-bottom: 4px; }
.discuss-item .who b { color: var(--text); }
.discuss-item .content { font-size: 14px; white-space: pre-wrap; }

/* ============ 管理 ============ */
.admin-tabs { display: flex; gap: 6px; margin-bottom: 18px; }
.admin-tabs button { border: 1px solid var(--border); background: #fff; padding: 7px 18px; border-radius: 9px; font-size: 14px; font-weight: 600; color: var(--text-2); }
.admin-tabs button.on { background: var(--primary); border-color: var(--primary); color: #fff; }

.provider-row { display: flex; align-items: center; gap: 12px; padding: 12px 16px; border-bottom: 1px solid #f3f4f6; font-size: 14px; }
.provider-row:last-child { border-bottom: none; }
.provider-row .dot { width: 9px; height: 9px; border-radius: 50%; }
.dot.ok { background: var(--ac); box-shadow: 0 0 6px var(--ac); }
.dot.bad { background: var(--wa); }
.provider-row .pname { font-weight: 700; min-width: 110px; }
.provider-row .pmodel { font-family: var(--mono); font-size: 12.5px; color: var(--text-2); }

/* ============ 杂项 ============ */
.muted { color: var(--text-2); }
.small { font-size: 13px; }
.mt { margin-top: 16px; }
.mb { margin-bottom: 16px; }
.flex { display: flex; align-items: center; gap: 10px; }
.spacer { flex: 1; }
.mono { font-family: var(--mono); }
.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
@media (max-width: 760px) { .grid2 { grid-template-columns: 1fr; } }

/* ============ 自适应学习（今日任务 / 学情分析）============ */
.prof-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); gap: 12px; margin-top: 12px; }
.prof-cell { background: #f9fafb; border: 1px solid var(--border); border-radius: 10px; padding: 12px 14px; display: flex; flex-direction: column; gap: 4px; }
.prof-cell .pk { font-size: 12.5px; color: var(--text-2); }
.prof-cell .pv { font-size: 18px; font-weight: 800; font-family: var(--mono); color: var(--primary); }

.task-item { display: flex; gap: 14px; padding: 16px 20px; border-bottom: 1px solid #f3f4f6; align-items: flex-start; }
.task-item:last-child { border-bottom: none; }
.task-item.ti-done { opacity: .62; }
.ti-no { width: 26px; height: 26px; border-radius: 50%; background: var(--primary); color: #fff; display: flex; align-items: center; justify-content: center; font-size: 13px; font-weight: 700; flex-shrink: 0; }
.ti-body { flex: 1; min-width: 0; }
.ti-head { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.ti-title { font-weight: 600; color: var(--text); }
.ti-diff { font-size: 12px; color: var(--text-2); }
.ti-reason { font-size: 13px; color: var(--text-2); margin-top: 6px; line-height: 1.6; }
.ti-act { flex-shrink: 0; }

.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-bottom: 16px; }
@media (max-width: 760px) { .two-col { grid-template-columns: 1fr; } }

.stat-row { display: grid; grid-template-columns: repeat(auto-fit, minmax(130px, 1fr)); gap: 16px; }
.stat-card .sv { display: block; font-size: 27px; font-weight: 800; color: var(--primary); font-family: var(--mono); }
.stat-card .sk { display: block; font-size: 13px; color: var(--text-2); margin-top: 2px; }

.heat-row { display: flex; align-items: flex-end; gap: 6px; height: 110px; margin-top: 12px; }
.heat-cell { flex: 1; display: flex; flex-direction: column; justify-content: flex-end; align-items: center; height: 100%; }
.heat-bar { width: 100%; background: linear-gradient(180deg, #60a5fa, #2563eb); border-radius: 4px 4px 0 0; min-height: 6px; }
.heat-d { font-size: 10px; color: var(--text-2); margin-top: 4px; }

/* 错误类型名称较长（如「算法效率不足或死循环」），标签列需要更宽 */
.bar-row .bl { width: 110px; }

/* ============ 老师讲解 / AI 讲解 ============ */
.teach-sec { padding: 12px 0; border-bottom: 1px dashed var(--line); }
.teach-sec:last-child { border-bottom: none; }
.ts-h { font-weight: 700; font-size: 14px; margin-bottom: 8px; color: var(--text); }
.ts-b { font-size: 13.5px; color: var(--text-2); line-height: 1.75; }
.ts-steps, .ts-err { margin: 0; padding-left: 20px; font-size: 13.5px; color: var(--text-2); line-height: 1.85; }
.ts-steps li { margin-bottom: 3px; }
.ts-err { color: #b45309; }
.ts-err li { margin-bottom: 3px; }

.code-tabs { display: flex; gap: 6px; margin-bottom: 8px; }
.ct { border: 1px solid var(--line); background: #fff; border-radius: 8px; padding: 5px 14px;
      font-size: 12.5px; cursor: pointer; color: var(--text-2); }
.ct.on { background: var(--primary); border-color: var(--primary); color: #fff; font-weight: 600; }

.code-block { background: #0f172a; color: #e2e8f0; border-radius: 10px; padding: 14px 16px;
  font-family: var(--mono); font-size: 12.5px; line-height: 1.7; overflow-x: auto;
  white-space: pre; margin: 0; }

.kp-box { background: #f8fafc; border: 1px solid var(--line); border-radius: 10px;
  padding: 11px 13px; margin-bottom: 9px; }
.kp-n { font-weight: 700; font-size: 13.5px; color: var(--primary); margin-bottom: 4px; }
.kp-c, .kp-h, .kp-w { font-size: 13px; color: var(--text-2); line-height: 1.7; margin-top: 3px; }
.kp-w { color: #b45309; }

.teach-tip { margin-top: 12px; background: #fffbeb; border: 1px solid #fde68a;
  border-radius: 10px; padding: 10px 13px; font-size: 13.5px; color: #92400e; }

.explain-modes { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; }
@media (max-width: 560px) { .explain-modes { grid-template-columns: 1fr; } }
.em { display: flex; flex-direction: column; align-items: flex-start; gap: 2px;
  background: #fff; border: 1px solid var(--line); border-radius: 10px; padding: 10px 11px;
  cursor: pointer; text-align: left; transition: border-color .15s, box-shadow .15s; }
.em:hover { border-color: var(--primary); }
.em.on { border-color: var(--primary); box-shadow: 0 0 0 2px rgba(37,99,235,.12); }
.em .em-i { font-size: 17px; }
.em b { font-size: 13px; }
.em i { font-style: normal; font-size: 11.5px; color: var(--text-2); }
.explain-note { font-size: 12px; color: var(--text-2); margin-top: 10px; line-height: 1.6; }

/* ============ 大模型选择器容器（自己服务器 / 外部大厂）============ */
.ai-picker-wrap {
  background: #f7f9fc;
  border: 1px solid var(--border, #e5e7eb);
  border-radius: 12px;
  padding: 10px 12px;
  margin-bottom: 12px;
}
.ai-picker-wrap .aip-src { margin-bottom: 8px; }
.ai-picker-wrap .aip-src label {
  font-size: 13px;
  padding: 6px 12px;
}

/* ============ 移动端断点（F5）============
   375px 手机上顶栏导航折行重叠、题库表 7 列被裁掉，这里统一兜底。 */
@media (max-width: 760px) {
  .topbar {
    height: auto;
    min-height: 56px;
    flex-wrap: wrap;
    gap: 8px 14px;
    padding: 8px 14px;
  }
  .brand { flex: 1; min-width: 0; }
  .brand-badge { display: none; }
  /* 导航折到第二行，横向可滚动，不与品牌/用户区重叠 */
  .nav {
    order: 3;
    width: 100%;
    flex: none;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
  }
  .nav a { padding: 7px 10px; white-space: nowrap; }
  .userbox { gap: 8px; font-size: 13px; }
  .view { padding: 18px 14px 48px; }

  /* 7 列题库表小屏横向滚动而不是被 overflow:hidden 裁掉 */
  .list-card { overflow-x: auto; }
  .prob-table { min-width: 640px; }

  /* Toast 不超出屏幕 */
  #toast-wrap {
    right: 16px;
    left: auto;
    max-width: calc(100vw - 32px);
  }
  .toast { max-width: calc(100vw - 48px); }
}