/*!
 * 《逻辑小侦探》样式表
 *
 * 配色思路：暖色调背景 + 白卡片 + 高对比的大字。
 * 四个逻辑符号各有固定颜色（且=蓝 或=橙 非=红 蕴含=紫），
 * 孩子看久了会形成条件反射，这对理解抽象符号帮助很大。
 */

:root {
  --bg-1: #eef4ff;
  --bg-2: #fdf7ec;
  --ink: #1f2937;
  --ink-soft: #55637a;
  --ink-faint: #8b97ab;
  --line: #e2e8f4;
  --card: #ffffff;

  --accent: #5b6ef5;
  --accent-dark: #4353d6;
  --success: #16a34a;
  --warn: #ea9c0b;
  --danger: #dc2626;

  /* 四个逻辑符号的颜色 */
  --c-and: #2563eb;
  --c-or: #ea580c;
  --c-not: #dc2626;
  --c-imp: #9333ea;
  --c-false: #7f1d1d;

  --radius: 16px;
  --shadow: 0 2px 4px rgba(31, 41, 55, .05), 0 8px 24px rgba(31, 41, 55, .07);
  --shadow-lift: 0 4px 10px rgba(31, 41, 55, .09), 0 16px 36px rgba(31, 41, 55, .12);
}

* { box-sizing: border-box; }

/*
 * 重要：HTML 的 hidden 属性只是 UA 样式表里的 `display: none`，
 * 任何自己写了 display 的类（.modal 的 grid、.pick-banner 的 flex……）
 * 都会把它盖掉，于是「隐藏」的元素照样显示出来。
 * 这一条 !important 是修这个坑的标准做法，别删。
 */
[hidden] { display: none !important; }

html, body {
  margin: 0;
  padding: 0;
  min-height: 100%;
}

body {
  font-family: "Microsoft YaHei", "PingFang SC", "Hiragino Sans GB",
               "Noto Sans CJK SC", "Source Han Sans SC", system-ui, sans-serif;
  font-size: 17px;
  line-height: 1.75;
  color: var(--ink);
  background: linear-gradient(160deg, var(--bg-1) 0%, var(--bg-2) 100%);
  background-attachment: fixed;
  -webkit-text-size-adjust: 100%;
}

button { font-family: inherit; cursor: pointer; }

/* ------------------------------------------------------------ 顶栏 */

#topbar {
  position: sticky;
  top: 0;
  z-index: 40;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 18px;
  background: rgba(255, 255, 255, .86);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

#topbar-title {
  flex: 1;
  font-weight: 700;
  font-size: 18px;
  letter-spacing: .5px;
}

#topbar-right { display: flex; gap: 6px; }

.ghost {
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink-soft);
  border-radius: 10px;
  padding: 7px 14px;
  font-size: 15px;
  transition: .15s;
}
.ghost:hover { background: #f4f7ff; color: var(--ink); }
.ghost.icon { padding: 7px 10px; font-size: 16px; }
.ghost.small { padding: 3px 10px; font-size: 13px; }

.big-primary {
  border: none;
  border-radius: 14px;
  background: linear-gradient(180deg, var(--accent) 0%, var(--accent-dark) 100%);
  color: #fff;
  font-size: 19px;
  font-weight: 700;
  padding: 14px 34px;
  box-shadow: 0 6px 0 #3543b8, 0 10px 22px rgba(91, 110, 245, .34);
  transition: transform .08s, box-shadow .08s;
}
.big-primary:hover { transform: translateY(-1px); }
.big-primary:active {
  transform: translateY(4px);
  box-shadow: 0 2px 0 #3543b8, 0 5px 12px rgba(91, 110, 245, .3);
}

.danger {
  border: 1px solid #f3c4c4;
  background: #fff5f5;
  color: var(--danger);
  border-radius: 10px;
  padding: 9px 16px;
  font-size: 15px;
}
.danger:hover { background: #ffe9e9; }

/* ------------------------------------------------------------ 布局 */

#main { max-width: 1120px; margin: 0 auto; padding: 22px 18px 70px; }

.screen { animation: fade-in .22s ease; }
@keyframes fade-in {
  from { opacity: 0; transform: translateY(6px); }
  to   { opacity: 1; transform: none; }
}

.section-title {
  font-size: 20px;
  margin: 34px 0 14px;
  color: var(--ink-soft);
  font-weight: 700;
}

/* ------------------------------------------------------------ 首页 */

.hero { text-align: center; padding: 26px 0 8px; }
.hero-emoji { font-size: 68px; line-height: 1; animation: bob 3s ease-in-out infinite; }
@keyframes bob {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(-8px); }
}

.hero h1 {
  font-size: 42px;
  margin: 10px 0 6px;
  letter-spacing: 3px;
  background: linear-gradient(120deg, #5b6ef5, #9333ea 60%, #ea580c);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero-sub { color: var(--ink-soft); margin: 0 0 16px; font-size: 17px; }

.hero-stats {
  display: flex;
  justify-content: center;
  gap: 26px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}
.hero-stats .stat { text-align: center; }
.hero-stats .stat b { display: block; font-size: 26px; color: var(--accent); }
.hero-stats .stat span { font-size: 13px; color: var(--ink-faint); }

.world-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(238px, 1fr));
  gap: 16px;
}

.world-card {
  position: relative;
  background: var(--card);
  border-radius: var(--radius);
  padding: 18px 18px 16px;
  box-shadow: var(--shadow);
  border: 1px solid var(--line);
  border-top: 5px solid var(--wc, var(--accent));
  cursor: pointer;
  transition: transform .14s, box-shadow .14s;
  text-align: left;
  width: 100%;
  display: block;
}
.world-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-lift); }
.world-card.locked {
  cursor: not-allowed;
  opacity: .55;
  filter: grayscale(.5);
  border-top-color: var(--ink-faint);
}
.world-card.locked:hover { transform: none; box-shadow: var(--shadow); }
.world-card .world-emoji { font-size: 34px; }
.world-card .world-name { font-size: 19px; font-weight: 700; margin: 4px 0 2px; }
.world-card .world-desc { font-size: 14px; color: var(--ink-soft); line-height: 1.55; min-height: 44px; }
.world-card .world-lock { font-size: 13px; color: var(--ink-faint); margin-top: 6px; }

.progress-bar {
  height: 8px;
  border-radius: 99px;
  background: #eef1f8;
  overflow: hidden;
  margin-top: 10px;
}
.progress-fill {
  height: 100%;
  border-radius: 99px;
  background: linear-gradient(90deg, var(--wc, var(--accent)), var(--accent));
  transition: width .4s;
}
.progress-text { font-size: 13px; color: var(--ink-faint); margin-top: 5px; }

.footer-note {
  text-align: center;
  color: var(--ink-faint);
  font-size: 13px;
  margin-top: 40px;
}

/* ------------------------------------------------------------ 世界页 */

.world-head {
  border-radius: var(--radius);
  padding: 22px 24px;
  background: var(--card);
  box-shadow: var(--shadow);
  border-left: 6px solid var(--wc, var(--accent));
  margin-bottom: 20px;
}
.world-head h2 { margin: 0 0 4px; font-size: 25px; }
.world-head .wh-desc { color: var(--ink-soft); font-size: 15px; margin-bottom: 8px; }
.world-head .markdown { color: var(--ink-soft); font-size: 15px; }
.world-head .markdown p { margin: 6px 0; }
.world-head .markdown b { color: var(--ink); }

.level-list { display: flex; flex-direction: column; gap: 11px; }

.level-item {
  display: flex;
  align-items: center;
  gap: 15px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 14px 18px;
  box-shadow: var(--shadow);
  cursor: pointer;
  transition: transform .12s, box-shadow .12s;
  width: 100%;
  text-align: left;
}
.level-item:hover { transform: translateX(4px); box-shadow: var(--shadow-lift); }
.level-item.locked { opacity: .5; filter: grayscale(.6); cursor: not-allowed; }
.level-item.locked:hover { transform: none; }

.level-num {
  flex: none;
  width: 42px; height: 42px;
  border-radius: 12px;
  display: grid; place-items: center;
  font-weight: 700; font-size: 17px;
  background: #eef2ff; color: var(--accent);
}
.level-item.done .level-num { background: #dcfce7; color: var(--success); }
.level-item .level-title { flex: 1; font-size: 17px; font-weight: 600; }
.level-item .level-kind { font-size: 12px; color: var(--ink-faint); font-weight: 400; }
.level-item .level-status { font-size: 20px; }

/* ------------------------------------------------------------ 关卡：通用 */

.level-head {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
  margin-bottom: 14px;
}
.level-head h2 { flex: 1; margin: 0; font-size: 22px; min-width: 180px; }
.level-tools { display: flex; gap: 8px; }

.tool {
  border: 1px solid var(--line);
  background: #fff;
  border-radius: 11px;
  padding: 8px 15px;
  font-size: 15px;
  color: var(--ink-soft);
  transition: .14s;
}
.tool:hover:not(:disabled) { background: #f4f7ff; color: var(--ink); border-color: #c7d2fe; }
.tool:disabled { opacity: .4; cursor: not-allowed; }

.feedback {
  border-radius: 13px;
  padding: 13px 18px;
  margin-bottom: 14px;
  font-size: 16px;
  animation: pop-in .2s ease;
}
.feedback.good { background: #ecfdf5; border: 1px solid #a7f3d0; color: #065f46; }
.feedback.bad  { background: #fff7ed; border: 1px solid #fed7aa; color: #9a3412; }
.feedback.info { background: #eff6ff; border: 1px solid #bfdbfe; color: #1e40af; }
@keyframes pop-in {
  from { opacity: 0; transform: scale(.97); }
  to   { opacity: 1; transform: none; }
}

.pick-banner {
  display: flex;
  align-items: center;
  gap: 12px;
  background: linear-gradient(90deg, #fef3c7, #fde68a);
  border: 1px solid #fcd34d;
  color: #92400e;
  border-radius: 13px;
  padding: 11px 16px;
  margin-bottom: 14px;
  font-weight: 600;
  font-size: 16px;
}
.pick-banner span { flex: 1; }
.pick-banner button {
  border: 1px solid #f0b429; background: #fffdf5; color: #92400e;
  border-radius: 9px; padding: 4px 12px; font-size: 14px;
}

.pane-title {
  font-size: 14px;
  font-weight: 700;
  color: var(--ink-faint);
  letter-spacing: 1px;
  margin: 0 0 9px;
}

/* ------------------------------------------------------------ 案情简介 */

.case-brief {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  margin-bottom: 14px;
  overflow: hidden;
}
.case-brief > summary {
  cursor: pointer;
  padding: 12px 18px;
  font-weight: 700;
  font-size: 16px;
  color: var(--ink);
  list-style: none;
  user-select: none;
}
.case-brief > summary::-webkit-details-marker { display: none; }
.case-brief > summary::after {
  content: "▾";
  float: right;
  color: var(--ink-faint);
  transition: transform .18s;
}
.case-brief[open] > summary::after { transform: rotate(180deg); }
.case-brief > summary:hover { background: #f7f9ff; }
.case-brief .markdown {
  padding: 2px 20px 16px;
  font-size: 16px;
  color: var(--ink-soft);
  border-top: 1px solid var(--line);
  padding-top: 12px;
}
.case-brief .markdown b { color: var(--ink); }
.case-brief .markdown p { margin: 7px 0; }

/* ------------------------------------------------------------ 公式选择器 */

.formula-picker {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  background: #faf5ff;
  border: 1px solid #e9d5ff;
  border-radius: 13px;
  padding: 14px 16px;
  margin-bottom: 14px;
}
.formula-chip {
  background: #fff;
  border: 1px solid #ddd6fe;
  border-bottom: 3px solid var(--c-imp);
  border-radius: 11px;
  padding: 9px 16px;
  font-size: 17px;
  transition: .13s;
}
.formula-chip:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
  background: #fdfbff;
}
.formula-picker .picker-note {
  width: 100%;
  font-size: 13px;
  color: var(--ink-faint);
}

/* ------------------------------------------------------------ 证明关 */

.proof-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 268px;
  gap: 18px;
  align-items: start;
}

.goal-box {
  background: linear-gradient(150deg, #eef2ff, #ffffff);
  border: 2px dashed #a5b4fc;
  border-radius: var(--radius);
  padding: 16px 20px;
  margin-bottom: 16px;
}
.goal-box .goal-label {
  font-size: 13px; font-weight: 700; color: var(--accent);
  letter-spacing: 1px; margin-bottom: 6px;
}
.goal-box .goal-formula { font-size: 26px; font-weight: 600; line-height: 1.5; }
.goal-box .goal-note { font-size: 13px; color: var(--ink-faint); margin-top: 6px; }

.assume-box {
  background: linear-gradient(150deg, #faf5ff, #ffffff);
  border: 2px dashed #d8b4fe;
  border-radius: var(--radius);
  padding: 13px 18px;
  margin-bottom: 16px;
}
.assume-box .assume-label {
  font-size: 13px; font-weight: 700; color: var(--c-imp);
  letter-spacing: 1px; margin-bottom: 8px;
}
.assume-box .clue { background: #faf5ff; border-color: #e9d5ff; }

.clue-list { display: flex; flex-direction: column; gap: 9px; }

.clue {
  display: flex;
  align-items: center;
  gap: 11px;
  background: #fbfcff;
  border: 1px solid var(--line);
  border-left: 4px solid #cbd5e1;
  border-radius: 12px;
  padding: 11px 15px;
  font-size: 18px;
  transition: .14s;
}
.clue .clue-no {
  flex: none;
  width: 24px; height: 24px;
  border-radius: 7px;
  background: #eef2ff; color: var(--accent);
  display: grid; place-items: center;
  font-size: 13px; font-weight: 700;
}
.clue.given   { border-left-color: #60a5fa; }
.clue.derived { border-left-color: #34d399; background: #f6fffb; }
.clue.assume  { border-left-color: #c084fc; }
/* 规则：普遍成立的定律，变量是空位。和「线索」区分开，孩子才知道
   这条不是关于某个具体东西的，而是什么都能塞进去的。 */
.clue.rule    { border-left-color: #f59e0b; background: #fffdf5; }
.clue .clue-tag {
  font-size: 11px;
  color: var(--ink-faint);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 1px 6px;
  flex: none;
}
.clue.clickable { cursor: pointer; }
.clue.clickable:hover { background: #eef4ff; transform: translateX(3px); }
.clue.pickable { box-shadow: 0 0 0 3px #fde68a; }
.clue.selected {
  background: #eef4ff;
  box-shadow: 0 0 0 3px var(--accent);
  transform: translateX(4px);
}
.clue.dim { opacity: .35; }

.todo-box {
  margin-top: 16px;
  background: #fffdf5;
  border: 1px solid #fde68a;
  border-radius: 13px;
  padding: 12px 16px;
}
.todo-box .todo-title { font-size: 13px; font-weight: 700; color: #b45309; margin-bottom: 6px; }
.todo-box ol { margin: 0; padding-left: 22px; font-size: 14px; color: var(--ink-soft); }
.todo-box li { margin: 2px 0; }
.todo-box li.current { color: var(--ink); font-weight: 700; }

.proof-side {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 14px 16px;
  box-shadow: var(--shadow);
  max-height: 460px;
  overflow-y: auto;
  position: sticky;
  top: 78px;
}
.proof-log { font-size: 14px; color: var(--ink-soft); }
.log-item {
  padding: 8px 0 8px 12px;
  border-left: 2px solid var(--line);
  position: relative;
  line-height: 1.6;
}
.log-item:last-child { border-left-color: var(--accent); }
.log-item .log-step { font-weight: 700; color: var(--accent); margin-right: 4px; }
.log-empty { color: var(--ink-faint); font-size: 13px; }

/* ------------------------------------------------------------ 方法卡 */

.palette-wrap { margin-top: 20px; }

.card-palette {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(158px, 1fr));
  gap: 11px;
}

.card {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--card);
  border: 1px solid var(--line);
  border-bottom: 3px solid var(--tone, var(--accent));
  border-radius: 13px;
  padding: 12px 14px;
  font-size: 16px;
  font-weight: 600;
  color: var(--ink);
  text-align: left;
  transition: transform .1s, box-shadow .1s, background .14s;
  position: relative;
}
.card .card-emoji { font-size: 21px; flex: none; }
.card:hover:not(.disabled) {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lift);
  background: #fbfcff;
}
.card:active:not(.disabled) { transform: translateY(0); }
.card.disabled {
  opacity: .38;
  cursor: not-allowed;
  border-bottom-color: var(--line);
}
.card.active {
  background: #eef4ff;
  box-shadow: 0 0 0 3px var(--accent);
}
.card .card-new {
  position: absolute;
  top: -8px; right: -6px;
  background: var(--warn);
  color: #fff;
  font-size: 10px;
  font-weight: 700;
  border-radius: 7px;
  padding: 1px 7px;
  letter-spacing: .5px;
}
.card.tip-shown { background: #fffbeb; }

/* ------------------------------------------------------------ 逻辑符号配色 */

.op { font-weight: 700; padding: 0 1px; }
.op-not   { color: var(--c-not); }
.op-and   { color: var(--c-and); }
.op-or    { color: var(--c-or); }
.op-imp   { color: var(--c-imp); }
.op-false { color: var(--c-false); }
.atom     { color: #0f766e; font-weight: 600; }

.legend {
  grid-column: 1 / -1;
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  font-size: 13px;
  color: var(--ink-faint);
  margin-top: 10px;
}

/* ------------------------------------------------------------ 选择题 */

.quiz-question {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px 24px;
  box-shadow: var(--shadow);
  font-size: 19px;
  line-height: 1.8;
  margin-bottom: 18px;
}

.quiz-options { display: flex; flex-direction: column; gap: 11px; }

.quiz-option {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  background: var(--card);
  border: 1px solid var(--line);
  border-left: 4px solid #cbd5e1;
  border-radius: 13px;
  padding: 15px 18px;
  font-size: 17px;
  text-align: left;
  transition: .14s;
  line-height: 1.65;
}
.quiz-option:hover:not(:disabled) {
  transform: translateX(4px);
  border-left-color: var(--accent);
  background: #fbfcff;
}
.quiz-option .opt-mark {
  flex: none;
  width: 26px; height: 26px;
  border-radius: 8px;
  background: #eef2ff; color: var(--accent);
  display: grid; place-items: center;
  font-weight: 700; font-size: 14px;
  margin-top: 1px;
}
.quiz-option.correct {
  background: #ecfdf5; border-color: #a7f3d0; border-left-color: var(--success);
}
.quiz-option.correct .opt-mark { background: #d1fae5; color: var(--success); }
.quiz-option.wrong {
  background: #fff1f2; border-color: #fecdd3; border-left-color: var(--danger);
}
.quiz-option.wrong .opt-mark { background: #ffe4e6; color: var(--danger); }
.quiz-option:disabled { cursor: default; }
.quiz-option.dimmed { opacity: .5; }

/* ------------------------------------------------------------ 通关页 */

.done-card {
  background: var(--card);
  border-radius: 22px;
  padding: 34px 30px 28px;
  box-shadow: var(--shadow-lift);
  text-align: center;
  max-width: 720px;
  margin: 20px auto;
  border-top: 6px solid var(--success);
  animation: pop-in .3s ease;
}
.done-emoji { font-size: 62px; animation: bob 1.6s ease-in-out infinite; }
.done-card h2 { font-size: 28px; margin: 8px 0 18px; color: var(--success); }
.done-card .markdown {
  text-align: left;
  background: #f8fafc;
  border-radius: 14px;
  padding: 18px 22px;
  font-size: 16px;
  color: var(--ink-soft);
  line-height: 1.85;
}
.done-card .markdown b { color: var(--ink); }
.done-xp { margin: 16px 0 4px; font-size: 15px; color: var(--warn); font-weight: 700; }
.done-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
  align-items: center;
  margin-top: 22px;
  flex-wrap: wrap;
}

/* ------------------------------------------------------------ markdown */

.markdown p { margin: 8px 0; }
.markdown b { color: var(--ink); font-weight: 700; }
.markdown code {
  background: #eef2ff;
  border-radius: 6px;
  padding: 1px 6px;
  font-family: "Cascadia Mono", Consolas, monospace;
  font-size: .92em;
  color: var(--accent-dark);
}
.markdown .sp { height: 8px; }

/* ------------------------------------------------------------ 设置弹层 */

.modal {
  position: fixed;
  inset: 0;
  background: rgba(22, 30, 46, .45);
  display: grid;
  place-items: center;
  z-index: 90;
  padding: 20px;
}
.modal-card {
  background: #fff;
  border-radius: 20px;
  padding: 26px 28px;
  max-width: 480px;
  width: 100%;
  box-shadow: var(--shadow-lift);
}
.modal-card h3 { margin: 0 0 18px; font-size: 21px; }
.switch-row {
  display: flex;
  align-items: flex-start;
  gap: 11px;
  padding: 11px 0;
  border-bottom: 1px solid var(--line);
  font-size: 15px;
  color: var(--ink-soft);
  cursor: pointer;
  line-height: 1.6;
}
.switch-row input { margin-top: 5px; width: 18px; height: 18px; accent-color: var(--accent); flex: none; }
.switch-row b { color: var(--ink); }
.modal-actions {
  display: flex;
  gap: 12px;
  justify-content: space-between;
  align-items: center;
  margin-top: 22px;
  flex-wrap: wrap;
}
.modal-actions .big-primary { font-size: 16px; padding: 11px 26px; box-shadow: 0 4px 0 #3543b8; }

/* ------------------------------------------------------------ 撒花 */

.confetti {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 80;
  overflow: hidden;
}
.confetti span {
  position: absolute;
  top: -20px;
  font-size: 22px;
  animation: fall linear forwards;
}
@keyframes fall {
  to { transform: translateY(105vh) rotate(540deg); opacity: .2; }
}

/* ------------------------------------------------------------ 介绍关（先教后考） */

.teach-card {
  background: var(--card);
  border-radius: 22px;
  padding: 32px 34px 30px;
  box-shadow: var(--shadow-lift);
  max-width: 760px;
  margin: 8px auto;
  border-top: 6px solid var(--accent);
}
.teach-symbol {
  font-size: 78px;
  line-height: 1.1;
  text-align: center;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 4px;
  letter-spacing: 2px;
}
.teach-card h2 {
  text-align: center;
  font-size: 24px;
  margin: 0 0 20px;
  color: var(--ink);
}
.teach-card .markdown {
  font-size: 17px;
  line-height: 1.95;
  color: var(--ink-soft);
}
.teach-card .markdown b { color: var(--ink); }
.teach-card .markdown p { margin: 9px 0; }
.teach-card .markdown .sp { height: 10px; }
.teach-card .big-primary {
  display: block;
  margin: 28px auto 0;
}

/* ------------------------------------------------------------ 新道具介绍弹层 */

.modal-card.wide { max-width: 620px; max-height: 88vh; overflow-y: auto; }
.modal-sub {
  color: var(--ink-faint);
  font-size: 14px;
  margin: -10px 0 16px;
  line-height: 1.6;
}
.intro-list { display: flex; flex-direction: column; gap: 12px; }
.intro-item {
  background: #fbfcff;
  border: 1px solid var(--line);
  border-left: 5px solid var(--tone, var(--accent));
  border-radius: 14px;
  padding: 14px 18px;
}
.intro-item .ii-head {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 19px;
  font-weight: 700;
  margin-bottom: 6px;
}
.intro-item .ii-tip { color: var(--ink-soft); font-size: 15px; line-height: 1.7; }
.intro-item .ii-when {
  margin-top: 9px;
  font-size: 14px;
  color: var(--accent-dark);
  background: #eef2ff;
  border-radius: 9px;
  padding: 8px 12px;
  line-height: 1.6;
}
.intro-item .ii-ex {
  margin-top: 7px;
  font-size: 13px;
  color: var(--ink-faint);
  line-height: 1.6;
}

/* ------------------------------------------------------------ 武器库 */

.inv-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
.inv-head h3 { margin: 0; }
.inv-tabs { display: flex; gap: 8px; margin: 4px 0 16px; }
.inv-tab {
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink-soft);
  border-radius: 11px;
  padding: 8px 16px;
  font-size: 15px;
  transition: .14s;
}
.inv-tab:hover { background: #f4f7ff; }
.inv-tab.active {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
  font-weight: 700;
}
.inv-body {
  max-height: 60vh;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.inv-group-title {
  font-size: 14px;
  font-weight: 700;
  color: var(--ink-faint);
  letter-spacing: 1px;
  margin-bottom: -6px;
}
.inv-group {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(238px, 1fr));
  gap: 12px;
}
/* 武器库比新道具弹层宽一些：要放得下三列卡 */
.modal-card.inventory { max-width: 880px; }
.inv-item {
  background: #fbfcff;
  border: 1px solid var(--line);
  border-bottom: 4px solid var(--tone, var(--accent));
  border-radius: 14px;
  padding: 13px 16px;
}
.inv-item .iv-head {
  display: flex;
  align-items: center;
  gap: 9px;
  font-size: 17px;
  font-weight: 700;
  margin-bottom: 5px;
}
.inv-item .iv-tip { font-size: 14px; color: var(--ink-soft); line-height: 1.65; }
.inv-item .iv-when { margin-top: 8px; font-size: 13px; color: var(--accent-dark); line-height: 1.6; }
.inv-item .iv-when b, .inv-item .iv-tip b { color: var(--ink); }
.inv-item .iv-ex { margin-top: 6px; font-size: 13px; color: var(--ink-faint); line-height: 1.6; }
.inv-item.locked { opacity: .48; filter: grayscale(.65); border-bottom-color: var(--line); }
.inv-item .iv-lock { margin-top: 8px; font-size: 13px; color: var(--ink-faint); }
.inv-item .iv-sym {
  font-size: 32px;
  font-weight: 700;
  line-height: 1;
  text-align: center;
  margin-bottom: 8px;
}
.inv-item .iv-new {
  background: var(--warn);
  color: #fff;
  font-size: 10px;
  border-radius: 6px;
  padding: 1px 6px;
  font-weight: 700;
}
.inv-empty { color: var(--ink-faint); font-size: 14px; }

/* ------------------------------------------------------------ 补理由关 */

.justify-givens { margin: 16px 0 20px; }

.justify-steps { display: flex; flex-direction: column; gap: 10px; }

.justify-step {
  display: flex;
  align-items: center;
  gap: 13px;
  background: var(--card);
  border: 1.5px solid var(--line);
  border-radius: 13px;
  padding: 12px 16px;
  transition: border-color .12s, background .12s;
}
.justify-step .js-num {
  flex: none;
  width: 26px; height: 26px;
  border-radius: 8px;
  display: grid; place-items: center;
  font-weight: 700; font-size: 14px;
  background: #eef2ff; color: var(--accent);
}
.justify-step .js-claim { flex: 1; font-size: 16px; line-height: 1.6; }
.justify-step select {
  flex: none;
  font: inherit;
  font-size: 14px;
  padding: 7px 10px;
  border: 1.5px solid var(--line);
  border-radius: 9px;
  background: #fcfdff;
  cursor: pointer;
  max-width: 15em;
}
.justify-step select:focus { outline: none; border-color: var(--accent); }
.justify-step.ok { border-color: #16a34a; background: #f0fdf4; }
.justify-step.ok select { border-color: #16a34a; }
.justify-step.no { border-color: #dc2626; background: #fef2f2; }
.justify-step.no select { border-color: #dc2626; }

/* ------------------------------------------------------------ 讲解关 */

.explain-prompt {
  font-size: 15px;
  color: var(--ink-soft);
  background: #f8fafc;
  border-radius: 11px;
  padding: 12px 16px;
  margin: 16px 0;
  line-height: 1.7;
}
.explain-prompt b { color: var(--accent); }

.explain-steps { display: flex; flex-direction: column; gap: 10px; }

.explain-step {
  display: flex;
  align-items: flex-start;
  gap: 13px;
  width: 100%;
  text-align: left;
  font: inherit;
  background: var(--card);
  border: 1.5px solid var(--line);
  border-radius: 13px;
  padding: 13px 16px;
  cursor: pointer;
  transition: all .12s;
}
.explain-step:hover { border-color: var(--accent); transform: translateX(3px); }
.explain-step.wrong {
  border-color: #dc2626;
  background: #fef2f2;
  transform: none;
}
.explain-step .es-num {
  flex: none;
  width: 26px; height: 26px;
  border-radius: 8px;
  display: grid; place-items: center;
  font-weight: 700; font-size: 14px;
  background: #eef2ff; color: var(--accent);
}
.explain-step.wrong .es-num { background: #fee2e2; color: #dc2626; }
.explain-step .es-body { flex: 1; min-width: 0; }
.explain-step .es-claim { display: block; font-size: 16px; line-height: 1.6; }
.explain-step .es-why {
  display: block;
  font-size: 13px;
  color: var(--ink-faint);
  margin-top: 4px;
  line-height: 1.5;
}

/* ------------------------------------------------------------ 课程进度条 */

.course-banner {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 15px;
  padding: 10px 16px;
  border-radius: 11px;
  margin-bottom: 16px;
  border-left: 4px solid var(--accent);
  background: #eef2ff;
  color: var(--ink-soft);
}
.course-banner.review {
  border-left-color: #f59e0b;
  background: #fffbeb;
}
.course-banner b { color: var(--ink); }
.course-banner .cb-count {
  margin-left: auto;
  font-weight: 700;
  font-size: 14px;
  color: var(--accent);
  background: #fff;
  border-radius: 8px;
  padding: 2px 10px;
}
.course-banner.review .cb-count { color: #b45309; }

/* ------------------------------------------------------------ 小结关 */

.sum-graduation {
  background: #eef2ff;
  border: 1px solid #c7d2fe;
  border-radius: 13px;
  padding: 14px 18px;
  margin: 18px 0;
}
.sum-graduation b { color: var(--accent); font-size: 15px; }
.sum-graduation > div { margin-top: 6px; }

.sum-ask { margin: 18px 0 6px; }
.sum-ask b { display: block; margin-bottom: 8px; font-size: 15px; }
.sum-ask textarea {
  width: 100%;
  box-sizing: border-box;
  font: inherit;
  font-size: 15px;
  line-height: 1.7;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 11px;
  background: #fcfdff;
  resize: vertical;
}
.sum-ask textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(91, 110, 245, 0.12);
}
.sum-hint { font-size: 13px; color: var(--ink-faint); margin-top: 7px; }

/* ------------------------------------------------------------ 自己出题 */

.create-section { margin: 18px 0; }
.create-pool,
.create-goals {
  display: flex;
  flex-wrap: wrap;
  gap: 9px;
  margin-top: 9px;
}

.create-chip {
  font: inherit;
  font-size: 15px;
  padding: 9px 15px;
  border-radius: 11px;
  border: 1.5px solid var(--line);
  background: var(--card);
  cursor: pointer;
  transition: all .12s;
  line-height: 1.4;
}
.create-chip:hover { border-color: var(--accent); }
.create-chip.on {
  border-color: var(--accent);
  background: #eef2ff;
  box-shadow: 0 0 0 3px rgba(91, 110, 245, 0.12);
}
.create-chip.goal.on {
  border-color: #16a34a;
  background: #f0fdf4;
  box-shadow: 0 0 0 3px rgba(22, 163, 74, 0.12);
}

.create-actions { margin: 22px 0 14px; }
.create-actions .big-primary { width: 100%; }

.create-play {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 6px;
}
.create-play button { flex: 1; min-width: 190px; }

/* ------------------------------------------------------------ 学习路线 */

.big-ghost {
  display: block;
  margin: 12px auto 0;
  font-size: 16px;
  padding: 10px 24px;
  border-radius: 13px;
}
.lessons-head { text-align: center; margin-bottom: 22px; }
.lessons-head h2 { font-size: 26px; margin: 0 0 8px; }
.lessons-sub { color: var(--ink-soft); font-size: 15px; line-height: 1.8; margin: 0; }
.lessons-sub b { color: var(--ink); }

.lessons-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 14px;
  justify-content: center;
  margin-top: 14px;
  font-size: 13px;
  color: var(--ink-faint);
}
.lessons-legend span { white-space: nowrap; }

/* 一课里各类关卡的顺序：🔁 3 → 📖 1 → ✏️ 5 → … */
.lc-flow {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 5px;
  margin: 6px 0 8px;
  font-size: 13px;
}
.lc-flow .fl {
  padding: 2px 8px;
  border-radius: 7px;
  background: #f1f5f9;
  color: var(--ink-soft);
  white-space: nowrap;
}
.lc-flow .fl.review { background: #fef3c7; color: #b45309; }
.lc-flow .fl.t-teach { background: #e0e7ff; color: #4338ca; }
.lc-flow .fl.t-quiz { background: #fce7f3; color: #be185d; }
.lc-flow .fl.t-summary { background: #dcfce7; color: #15803d; }
.lc-flow .fl.t-explain { background: #fee2e2; color: #b91c1c; }
.lc-flow .fl.t-justify { background: #e0f2fe; color: #0369a1; }
.lc-flow .fl.t-create { background: #f3e8ff; color: #7e22ce; }
.lc-flow .fl-arrow { color: var(--ink-faint); font-size: 11px; }

.lesson-list { display: flex; flex-direction: column; gap: 12px; }

.lesson-card {
  display: flex;
  align-items: center;
  gap: 16px;
  background: var(--card);
  border: 1px solid var(--line);
  border-left: 5px solid var(--accent);
  border-radius: 14px;
  padding: 14px 18px;
  box-shadow: var(--shadow);
  cursor: pointer;
  transition: transform .13s, box-shadow .13s;
}
.lesson-card:hover { transform: translateX(4px); box-shadow: var(--shadow-lift); }
.lesson-card.done { border-left-color: var(--success); }
.lesson-card.locked { opacity: .5; filter: grayscale(.6); cursor: not-allowed; }
.lesson-card.locked:hover { transform: none; box-shadow: var(--shadow); }

.lesson-card .lc-num {
  flex: none;
  width: 44px; height: 44px;
  border-radius: 12px;
  display: grid; place-items: center;
  font-weight: 700; font-size: 18px;
  background: #eef2ff; color: var(--accent);
}
.lesson-card.done .lc-num { background: #dcfce7; color: var(--success); }
.lesson-card .lc-main { flex: 1; min-width: 0; }
.lesson-card .lc-title { font-size: 18px; font-weight: 700; }
.lesson-card .lc-meta { font-size: 13px; color: var(--ink-faint); margin: 2px 0 6px; }
.lesson-card .lc-plan {
  font-size: 13.5px;
  color: var(--ink-soft);
  margin-bottom: 7px;
}
.lesson-card .lc-plan b { color: var(--accent); }
.lesson-card .lc-goal {
  font-size: 14px;
  color: var(--ink-soft);
  background: #f8fafc;
  border-radius: 9px;
  padding: 6px 11px;
  margin-bottom: 8px;
  line-height: 1.6;
}
.lesson-card .lc-goal b { color: var(--accent); }
.lesson-card .lc-go { flex: none; font-size: 15px; font-weight: 700; color: var(--accent); }

/* ------------------------------------------------------------ 窄屏 */

@media (max-width: 860px) {
  .proof-layout { grid-template-columns: 1fr; }
  .proof-side { position: static; max-height: 220px; order: 2; }
  .hero h1 { font-size: 32px; }
  #main { padding: 16px 12px 60px; }
  body { font-size: 16px; }
  .goal-box .goal-formula { font-size: 22px; }
}

@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
}