:root {
  --primary: #1a3a5c;
  --primary-light: #2c5f8a;
  --accent: #d4a017;
  --accent-light: #e8c54d;
  --bg: #f8f6f1;
  --card-bg: #ffffff;
  --text: #2c2c2c;
  --text-light: #666;
  --border: #e0ddd5;
  --green: #2d8659;
  --red: #c0392b;
  --blue: #2980b9;
  --sidebar-w: 280px;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
  font-family: "Segoe UI", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.8;
  font-size: 15px;
}
/* Sidebar */
#sidebar {
  position: fixed;
  top: 0; left: 0;
  width: var(--sidebar-w);
  height: 100vh;
  background: var(--primary);
  overflow-y: auto;
  padding: 20px 0;
  z-index: 100;
  transition: transform 0.3s;
}
#sidebar .logo {
  text-align: center;
  color: #fff;
  font-size: 20px;
  font-weight: 700;
  padding: 10px 20px 25px;
  border-bottom: 1px solid rgba(255,255,255,0.1);
  margin-bottom: 15px;
}
#sidebar .logo span { color: var(--accent); }
#sidebar nav a {
  display: block;
  color: rgba(255,255,255,0.75);
  text-decoration: none;
  padding: 8px 25px;
  font-size: 14px;
  transition: all 0.2s;
  border-left: 3px solid transparent;
}
#sidebar nav a:hover, #sidebar nav a.active {
  color: #fff;
  background: rgba(255,255,255,0.08);
  border-left-color: var(--accent);
}
#sidebar nav a.sub {
  padding-left: 45px;
  font-size: 13px;
}
#sidebar .toggle-btn {
  display: none;
}
/* Main content */
#main {
  margin-left: var(--sidebar-w);
  padding: 40px 50px;
  max-width: 1100px;
}
/* Mobile toggle */
#mobile-toggle {
  display: none;
  position: fixed;
  top: 15px; left: 15px;
  z-index: 101;
  font-size: 24px;
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: 5px;
  width: 40px; height: 40px;
  cursor: pointer;
}
/* Typography */
h1 { font-size: 32px; color: var(--primary); margin-bottom: 10px; }
h2 {
  font-size: 26px;
  color: var(--primary);
  margin: 50px 0 20px;
  padding-bottom: 10px;
  border-bottom: 3px solid var(--accent);
}
h3 {
  font-size: 20px;
  color: var(--primary-light);
  margin: 35px 0 15px;
}
h4 {
  font-size: 17px;
  color: var(--primary);
  margin: 25px 0 10px;
}
p { margin-bottom: 12px; }
a { color: var(--primary-light); }
/* Cover */
.cover {
  text-align: center;
  padding: 60px 30px 50px;
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  color: #fff;
  border-radius: 12px;
  margin-bottom: 40px;
}
.cover h1 { color: #fff; font-size: 36px; margin-bottom: 15px; }
.cover .subtitle { font-size: 18px; opacity: 0.9; margin-bottom: 8px; }
.cover .badge {
  display: inline-block;
  background: var(--accent);
  color: var(--primary);
  padding: 4px 16px;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 700;
  margin: 5px;
}
.cover .info {
  margin-top: 20px;
  font-size: 13px;
  opacity: 0.7;
}
/* Cards */
.card {
  background: var(--card-bg);
  border-radius: 10px;
  padding: 25px 30px;
  margin: 20px 0;
  box-shadow: 0 2px 8px rgba(0,0,0,0.06);
  border: 1px solid var(--border);
}
.card-accent {
  border-left: 4px solid var(--accent);
}
.card-blue { border-left: 4px solid var(--blue); }
.card-green { border-left: 4px solid var(--green); }
.card-red { border-left: 4px solid var(--red); }
/* Type cards */
.type-card {
  background: var(--card-bg);
  border-radius: 10px;
  padding: 0;
  margin: 25px 0;
  box-shadow: 0 2px 10px rgba(0,0,0,0.08);
  overflow: hidden;
  border: 1px solid var(--border);
}
.type-card .type-header {
  background: var(--primary);
  color: #fff;
  padding: 15px 25px;
  font-size: 18px;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.type-card .type-header .type-tag {
  background: var(--accent);
  color: var(--primary);
  padding: 3px 12px;
  border-radius: 15px;
  font-size: 12px;
}
.type-card .type-body { padding: 25px 30px; }
/* Structure blocks */
.structure-block {
  display: inline-block;
  text-align: center;
  padding: 12px 18px;
  margin: 5px;
  border-radius: 8px;
  font-size: 13px;
  vertical-align: top;
  min-width: 120px;
}
.sb-intro { background: #e8f0fe; color: #1a3a5c; border: 2px solid #1a3a5c; }
.sb-body { background: #e8f5e9; color: #2d8659; border: 2px solid #2d8659; }
.sb-conclusion { background: #fff3e0; color: #d4a017; border: 2px solid #d4a017; }
.sb-arrow {
  display: inline-block;
  margin: 0 2px;
  font-size: 20px;
  color: var(--text-light);
  vertical-align: middle;
}
/* Tables */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 15px 0;
  font-size: 14px;
}
th {
  background: var(--primary);
  color: #fff;
  padding: 10px 12px;
  text-align: left;
  font-weight: 600;
}
td {
  padding: 8px 12px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}
tr:nth-child(even) td { background: #faf9f6; }
/* Vocabulary */
.vocab-table td:first-child {
  font-weight: 600;
  color: var(--primary);
  white-space: nowrap;
}
.vocab-table td:nth-child(2) {
  font-style: italic;
  color: var(--blue);
}
/* Essay framework (论证框架) */
.essay-framework {
  background: linear-gradient(135deg, #f0f4ff 0%, #e8f0fe 100%);
  border: 1px solid #c5d5f5;
  border-radius: 10px;
  padding: 22px 25px;
  margin: 20px 0 8px 0;
  font-size: 14px;
  line-height: 1.8;
}
.essay-framework .fw-title {
  font-weight: 700;
  color: var(--primary);
  font-size: 15px;
  margin-bottom: 12px;
}
.essay-framework .fw-section {
  margin-bottom: 14px;
  padding-bottom: 12px;
  border-bottom: 1px dashed #c5d5f5;
}
.essay-framework .fw-section:last-child { border-bottom: none; margin-bottom: 0; padding-bottom: 0; }
.essay-framework .fw-row {
  display: flex;
  align-items: flex-start;
  margin-bottom: 4px;
}
.essay-framework .fw-label {
  background: var(--primary);
  color: #fff;
  padding: 2px 10px;
  border-radius: 4px;
  font-size: 12px;
  font-weight: 600;
  white-space: nowrap;
  margin-right: 10px;
  margin-top: 3px;
}
.essay-framework .fw-content { flex: 1; }
.essay-framework .fw-arrow { color: var(--primary); font-weight: 700; }
.essay-framework .fw-detail {
  margin: 6px 0 4px 0;
  padding-left: 12px;
  border-left: 3px solid #c5d5f5;
  font-size: 13px;
  color: #555;
  line-height: 1.7;
}
.essay-framework .fw-vocab {
  margin-top: 6px;
  font-size: 13px;
}
.essay-framework .fw-vocab-tag {
  display: inline-block;
  background: #e8f0fe;
  border: 1px solid #b8d0f5;
  border-radius: 4px;
  padding: 1px 8px;
  margin: 2px 4px 2px 0;
  font-size: 12px;
  color: var(--primary);
  font-weight: 500;
}
/* Essay blocks */
.essay-block {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 8px;
  margin: 20px 0;
  overflow: hidden;
}
.essay-question {
  background: #f0ebe1;
  padding: 15px 25px;
  font-size: 14px;
  border-bottom: 2px solid var(--accent);
}
.essay-question strong { color: var(--primary); }
.essay-body {
  padding: 20px 25px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}
.essay-original {
  font-size: 14px;
  line-height: 2;
}
.essay-analysis {
  font-size: 13px;
  line-height: 2;
  color: #555;
  border-left: 2px solid var(--accent);
  padding-left: 15px;
}
.essay-annotation {
  background: #fffde7;
  padding: 2px 5px;
  border-radius: 3px;
  font-weight: 600;
}
.essay-tag {
  display: inline-block;
  background: var(--green);
  color: #fff;
  padding: 1px 8px;
  border-radius: 10px;
  font-size: 11px;
  margin-left: 5px;
}
.essay-tag.vocab { background: var(--blue); }
.essay-tag.grammar { background: var(--purple, #8e44ad); }
.essay-tag.structure { background: var(--green); }
/* Logic Chain - Enhanced */
.logic-chain-box {
  margin-bottom: 22px;
  border-radius: 10px;
  border: 1px solid #c5d5f5;
  background: linear-gradient(135deg, #f0f4ff 0%, #e8f0fe 100%);
  overflow: hidden;
}
.logic-chain-box .lc-header {
  font-weight: 700;
  color: var(--primary);
  font-size: 15px;
  padding: 14px 22px 10px;
  border-bottom: 1px dashed #c5d5f5;
}
.logic-chain-box .lc-group {
  padding: 14px 22px;
  border-bottom: 1px dashed #c5d5f5;
}
.logic-chain-box .lc-group:last-child {
  border-bottom: none;
}
.logic-chain-box .lc-group-title {
  font-weight: 700;
  font-size: 14px;
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 6px;
}
.logic-chain-box .lc-group-title.pro {
  color: #27ae60;
}
.logic-chain-box .lc-group-title.con {
  color: #c0392b;
}
.logic-chain-box .lc-group-title.extra {
  color: #8e44ad;
}
.logic-chain-box .lc-item {
  margin-bottom: 14px;
  padding-left: 14px;
  border-left: 3px solid #b8d0f5;
}
.logic-chain-box .lc-item:last-child {
  margin-bottom: 0;
}
.logic-chain-box .lc-item-label {
  font-weight: 600;
  font-size: 13px;
  color: var(--primary);
  margin-bottom: 4px;
}
.logic-chain-box .lc-cn {
  font-size: 14px;
  line-height: 1.9;
  color: #2c3e50;
  padding: 6px 12px;
  background: rgba(52, 73, 94, 0.05);
  border-radius: 5px;
  margin-bottom: 4px;
}
.logic-chain-box .lc-en {
  font-size: 13px;
  line-height: 1.8;
  color: #666;
  font-style: italic;
  padding: 4px 12px;
}
.logic-chain-box .lc-arrow {
  color: var(--primary);
  font-weight: 700;
  margin: 0 1px;
}
/* Framework inside essay-block */
.essay-block .essay-framework {
  margin: 0;
  border-radius: 0;
  border-left: none;
  border-right: none;
  border-top: none;
  border-bottom: 2px solid var(--accent);
}
/* Collapsible Chinese translation */
.essay-translation {
  border-top: 1px solid #e0d6c6;
  background: #faf6f0;
}
.essay-translation summary {
  padding: 12px 25px;
  font-size: 14px;
  font-weight: 700;
  color: var(--primary);
  cursor: pointer;
  user-select: none;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 8px;
}
.essay-translation summary::-webkit-details-marker { display: none; }
.essay-translation summary::before {
  content: '\25B6';
  font-size: 10px;
  transition: transform 0.2s;
  display: inline-block;
}
.essay-translation[open] summary::before {
  transform: rotate(90deg);
}
.essay-translation[open] summary {
  border-bottom: 1px solid #e0d6c6;
}
.translation-content {
  padding: 15px 25px;
  font-size: 13px;
  line-height: 1.9;
  color: #666;
}
.translation-content p {
  margin: 0 0 8px 0;
}
.translation-content p:last-child {
  margin-bottom: 0;
}
/* Callout */
.callout {
  background: #fffde7;
  border-left: 4px solid var(--accent);
  padding: 15px 20px;
  margin: 15px 0;
  border-radius: 0 8px 8px 0;
  font-size: 14px;
}
.callout-title {
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 5px;
}
/* Pitfall */
.pitfall {
  background: #fce4ec;
  border-left: 4px solid var(--red);
  padding: 12px 18px;
  margin: 12px 0;
  border-radius: 0 8px 8px 0;
  font-size: 14px;
}
.pitfall strong { color: var(--red); }
/* Tip */
.tip {
  background: #e8f5e9;
  border-left: 4px solid var(--green);
  padding: 12px 18px;
  margin: 12px 0;
  border-radius: 0 8px 8px 0;
  font-size: 14px;
}
.tip strong { color: var(--green); }
/* Template boxes */
.template-box {
  background: #f5f7fa;
  border: 2px dashed var(--primary-light);
  border-radius: 8px;
  padding: 20px 25px;
  margin: 15px 0;
  font-size: 14px;
  line-height: 2.2;
}
.template-box .slot {
  display: inline-block;
  background: var(--accent-light);
  padding: 1px 8px;
  border-radius: 3px;
  font-weight: 600;
  color: var(--primary);
}
/* Collapsible */
.collapsible {
  cursor: pointer;
  background: var(--primary-light);
  color: #fff;
  padding: 10px 20px;
  border: none;
  text-align: left;
  font-size: 15px;
  font-weight: 600;
  width: 100%;
  border-radius: 8px;
  margin: 10px 0;
}
.collapsible:after {
  content: '▼';
  float: right;
}
.collapsible.active:after {
  content: '▲';
}
.collapsible-content {
  display: none;
  padding: 15px 0;
}
/* Score comparison */
.score-row {
  display: grid;
  grid-template-columns: 80px 1fr 1fr;
  gap: 10px;
  align-items: start;
  margin: 10px 0;
  padding: 10px;
  border-radius: 8px;
}
.score-label {
  font-weight: 700;
  text-align: center;
  padding: 8px;
  border-radius: 6px;
  color: #fff;
}
.score-5 { background: #c0392b; }
.score-6 { background: #e67e22; }
.score-7 { background: #27ae60; }
.score-8 { background: #1a3a5c; }
.score-content { font-size: 13px; }
.score-content .wrong { color: var(--red); text-decoration: line-through; }
.score-content .right { color: var(--green); font-weight: 600; }
/* Print */
@media print {
  #sidebar, #mobile-toggle { display: none !important; }
  #main { margin-left: 0; padding: 20px; }
  .collapsible-content { display: block !important; }
  .type-card, .card { page-break-inside: avoid; }
}
/* Mobile */
@media (max-width: 900px) {
  #sidebar { transform: translateX(-100%); }
  #sidebar.open { transform: translateX(0); }
  #mobile-toggle { display: block; }
  #main { margin-left: 0; padding: 20px; }
  .essay-body { grid-template-columns: 1fr; }
  .score-row { grid-template-columns: 60px 1fr; }
  .score-row > div:last-child { grid-column: 2; }
}
/* Section divider */
.divider {
  height: 3px;
  background: linear-gradient(90deg, var(--primary), var(--accent), var(--primary));
  margin: 60px 0;
  border-radius: 2px;
}
/* Topic badge */
.topic-badge {
  display: inline-block;
  padding: 3px 12px;
  border-radius: 15px;
  font-size: 12px;
  font-weight: 600;
  margin: 3px;
}
/* Watermark */
.watermark {
  position: fixed;
  bottom: 18px;
  right: 24px;
  z-index: 9999;
  background: rgba(255,255,255,0.92);
  border: 1px solid #d5cfc5;
  border-radius: 8px;
  padding: 8px 16px;
  font-size: 12px;
  color: #888;
  line-height: 1.6;
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
  pointer-events: none;
  user-select: none;
}
.watermark .wm-wechat {
  font-weight: 700;
  color: #2c3e50;
}