:root {
  --bg: #0f1419;
  --panel: #1a2030;
  --panel-2: #232b3d;
  --text: #e6edf3;
  --muted: #8b949e;
  --accent: #4fc3f7;
  --accent-2: #81c784;
  --accent-3: #ffb74d;
  --good: #66bb6a;
  --bad: #ef5350;
  --code-bg: #0d1117;
  --border: #30363d;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: -apple-system, "Hiragino Sans", "Noto Sans JP", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
}

/* ── Header ── */
header {
  padding: 28px 32px;
  border-bottom: 4px solid var(--accent);
}
header .day-label {
  font-size: 13px; font-weight: 700; letter-spacing: 2px;
  text-transform: uppercase; color: rgba(255,255,255,0.7);
  margin-bottom: 6px;
}
header h1 { margin: 0 0 12px; font-size: 22px; color: #fff; line-height: 1.4; }
.meta { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; font-size: 13px; }
.badge {
  background: rgba(0,0,0,0.3); padding: 4px 10px; border-radius: 12px;
  border: 1px solid rgba(255,255,255,0.2); color: #fff;
}
.difficulty { color: #ffd93d; letter-spacing: 2px; }

/* Phase header gradients */
.phase-1 { background: linear-gradient(135deg, #1565c0 0%, #0288d1 100%); }
.phase-2 { background: linear-gradient(135deg, #00695c 0%, #26a69a 100%); }
.phase-3 { background: linear-gradient(135deg, #4527a0 0%, #7e57c2 100%); }
.phase-4 { background: linear-gradient(135deg, #e65100 0%, #ff9800 100%); }
.phase-5 { background: linear-gradient(135deg, #880e4f 0%, #e91e63 100%); }

/* ── Layout ── */
.layout {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 24px;
  max-width: 1280px;
  margin: 0 auto;
  padding: 24px;
}
nav.toc {
  position: sticky; top: 24px;
  height: max-content;
  background: var(--panel);
  border-radius: 8px;
  padding: 16px;
  border: 1px solid var(--border);
  font-size: 14px;
}
nav.toc h3 {
  margin: 0 0 10px; font-size: 11px; color: var(--muted);
  text-transform: uppercase; letter-spacing: 1.5px;
}
nav.toc a {
  display: block; padding: 6px 10px;
  color: var(--text); text-decoration: none; border-radius: 4px;
  border-left: 2px solid transparent; transition: all 0.15s;
}
nav.toc a:hover { background: var(--panel-2); border-left-color: var(--accent); }
main { min-width: 0; }
section {
  background: var(--panel); border-radius: 10px;
  padding: 24px; margin-bottom: 20px;
  border: 1px solid var(--border);
}
section h2 {
  margin: 0 0 16px; color: var(--accent);
  border-bottom: 2px solid var(--border);
  padding-bottom: 10px; font-size: 18px;
}
section h3 { color: var(--accent-3); font-size: 15px; margin-top: 20px; }

/* ── Role cards ── */
.role-cards { display: flex; gap: 12px; flex-wrap: wrap; margin: 16px 0; }
.role-card {
  background: var(--panel-2); border-radius: 8px;
  padding: 12px 16px; border: 1px solid var(--border); min-width: 140px;
}
.role-card.you { border-top: 3px solid var(--accent-2); }
.role-label { font-size: 10px; color: var(--muted); text-transform: uppercase; letter-spacing: 1px; margin-bottom: 4px; }
.role-title { font-weight: 700; font-size: 14px; }
.role-sub { font-size: 12px; color: var(--muted); margin-top: 4px; }

/* ── Cultural note cards ── */
.notes-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin: 12px 0; }
.note-card {
  background: var(--panel-2); border-radius: 6px; padding: 12px;
  display: flex; gap: 10px; align-items: flex-start;
  border-left: 3px solid var(--accent-3);
}
.note-card.note-good { border-left-color: var(--good); }
.note-icon { font-size: 18px; flex-shrink: 0; margin-top: 2px; }
.note-text { font-size: 13px; line-height: 1.6; }

/* ── Situation tabs ── */
.tab-block { margin: 12px 0; }
.situation-tabs { display: flex; gap: 0; margin-bottom: 0; }
.sit-tab {
  padding: 8px 22px; background: var(--panel-2); color: var(--muted);
  border: 1px solid var(--border); cursor: pointer;
  font-size: 13px; font-weight: 700; transition: all 0.15s;
  border-radius: 0; border-bottom: none;
}
.sit-tab:first-child { border-radius: 6px 0 0 0; }
.sit-tab:last-child { border-radius: 0 6px 0 0; }
.sit-tab.active { background: var(--code-bg); color: var(--accent); border-top: 2px solid var(--accent); }
.sit-tab:hover:not(.active) { color: var(--text); background: var(--panel); }
.tab-panels {
  background: var(--code-bg); border-radius: 0 6px 6px 6px;
  border: 1px solid var(--border); padding: 20px;
}
.situation-panel { display: none; }
.situation-panel.active { display: block; }

.situation-header {
  padding: 8px 14px; border-radius: 5px;
  font-weight: 700; font-size: 14px; margin-bottom: 14px;
}
.sit-a { background: rgba(79,195,247,0.12); border-left: 3px solid var(--accent); color: var(--accent); }
.sit-b { background: rgba(129,199,132,0.12); border-left: 3px solid var(--accent-2); color: var(--accent-2); }
.sit-c { background: rgba(255,183,77,0.12); border-left: 3px solid var(--accent-3); color: var(--accent-3); }

/* ── Speech bubbles ── */
.speech-bubble {
  margin: 12px 0; padding: 12px 16px;
  border-radius: 8px; font-size: 14px;
}
.speech-bubble .speaker {
  font-size: 10px; font-weight: 700; text-transform: uppercase;
  letter-spacing: 1.5px; margin-bottom: 6px;
}
.speech-bubble p { margin: 0; line-height: 1.7; }
.bubble-emma {
  background: rgba(21,101,192,0.15); border-left: 3px solid #1e88e5;
  margin-right: 48px;
}
.bubble-emma .speaker { color: #64b5f6; }
.bubble-emma p { font-style: italic; }
.bubble-peer {
  background: rgba(103,58,183,0.15); border-left: 3px solid #7e57c2;
  margin-right: 48px;
}
.bubble-peer .speaker { color: #ce93d8; }
.bubble-you {
  background: rgba(27,94,32,0.2); border-left: 3px solid #43a047;
  margin-left: 48px;
}
.bubble-you .speaker { color: var(--accent-2); }

/* ── Task meta chips ── */
.task-meta { display: flex; gap: 8px; margin-top: 14px; flex-wrap: wrap; }
.chip {
  background: var(--panel-2); border: 1px solid var(--border);
  border-radius: 20px; padding: 3px 12px;
  font-size: 12px; color: var(--muted);
}

/* ── Phrase cards ── */
.phrase-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(210px, 1fr));
  gap: 10px; margin: 12px 0;
}
.phrase-card {
  background: var(--panel-2); border-radius: 8px;
  border: 1px solid var(--border); cursor: pointer;
  transition: border-color 0.2s; overflow: hidden;
}
.phrase-card:hover { border-color: var(--accent); }
.phrase-front { padding: 14px 16px; }
.phrase-jp { font-size: 15px; font-weight: 700; color: var(--accent-3); display: block; }
.phrase-hint { font-size: 11px; color: var(--muted); margin-top: 4px; display: block; }
.phrase-back {
  display: none; padding: 14px 16px;
  background: var(--code-bg); border-top: 1px solid var(--border);
}
.phrase-card.revealed .phrase-front { display: none; }
.phrase-card.revealed .phrase-back { display: block; }
.phrase-en { font-size: 13px; color: var(--accent); font-weight: 600; line-height: 1.6; display: block; }
.phrase-tip { font-size: 11px; color: var(--muted); margin-top: 8px; display: block; border-top: 1px solid var(--border); padding-top: 6px; }

/* ── Hints ── */
details.hint {
  background: var(--panel-2); border-radius: 6px;
  margin-bottom: 8px; border-left: 3px solid var(--accent-3);
}
details.hint summary {
  padding: 12px 16px; cursor: pointer;
  font-weight: 700; color: var(--accent-3); font-size: 14px;
  user-select: none; list-style: none;
}
details.hint summary::-webkit-details-marker { display: none; }
details.hint summary::before { content: '▶ '; font-size: 10px; margin-right: 4px; }
details.hint[open] summary::before { content: '▼ '; }
details.hint[open] summary { border-bottom: 1px solid var(--border); }
.hint-body { padding: 16px; }

/* ── SVG flow diagram ── */
.flow-wrap { overflow-x: auto; margin: 14px 0; }
.flow-wrap svg { display: block; max-width: 100%; height: auto; }

/* ── Skeleton template ── */
.skeleton-box {
  background: var(--code-bg); border-radius: 6px; padding: 14px 16px;
  border-left: 3px solid var(--muted); font-family: "JetBrains Mono", Menlo, monospace;
  font-size: 13px; line-height: 1.8; white-space: pre-wrap;
}
.skeleton-label { color: var(--muted); font-size: 12px; margin-bottom: 6px; font-style: italic; }
.sk-fill { color: var(--accent); }

/* ── Steps ── */
.step {
  background: var(--code-bg); border-left: 3px solid var(--accent);
  padding: 12px 16px; margin: 10px 0; border-radius: 4px;
  display: flex; gap: 12px; align-items: flex-start;
}
.step-num {
  background: var(--accent); color: #000; width: 26px; height: 26px;
  border-radius: 50%; display: flex; align-items: center; justify-content: center;
  font-weight: 800; font-size: 13px; flex-shrink: 0;
}
.step-body { font-size: 13px; line-height: 1.6; }
.step-body strong { color: var(--text); }

/* ── Key expressions table ── */
table {
  width: 100%; border-collapse: collapse; margin: 12px 0;
  background: var(--code-bg); border-radius: 6px; overflow: hidden;
}
th, td {
  padding: 10px 14px; text-align: left; font-size: 13px;
  border-bottom: 1px solid var(--border);
}
th { background: var(--panel-2); color: var(--accent-3); font-weight: 700; }
tr:last-child td { border-bottom: none; }
td code {
  background: var(--panel-2); padding: 2px 6px; border-radius: 3px;
  font-family: "JetBrains Mono", monospace; font-size: 12px; color: #e1bee7;
}

/* ── Comparison cards (mistakes) ── */
.comparison-card {
  display: grid; grid-template-columns: 1fr 28px 1fr;
  gap: 8px; align-items: center; margin: 10px 0;
}
.cmp-bad, .cmp-good {
  padding: 10px 14px; border-radius: 6px; font-size: 13px; line-height: 1.5;
}
.cmp-bad {
  background: rgba(239,83,80,0.12); border-left: 3px solid var(--bad);
  color: #ef9a9a;
}
.cmp-good {
  background: rgba(102,187,106,0.12); border-left: 3px solid var(--good);
  color: #a5d6a7;
}
.cmp-arrow { color: var(--muted); font-size: 18px; text-align: center; }
.cmp-reason { font-size: 11px; color: var(--muted); margin-top: 4px; padding-left: 4px; }

/* ── Level-up cards ── */
.level-chain { display: flex; flex-direction: column; gap: 4px; margin: 12px 0; }
.level-card {
  display: grid; grid-template-columns: 52px 1fr;
  gap: 12px; align-items: center;
  background: var(--code-bg); border-radius: 6px; padding: 10px 14px;
  border: 1px solid var(--border);
}
.lv-badge {
  font-size: 11px; font-weight: 700; text-align: center;
  padding: 3px 6px; border-radius: 4px;
}
.lv1 .lv-badge { background: rgba(255,183,77,0.2); color: var(--accent-3); }
.lv2 .lv-badge { background: rgba(79,195,247,0.2); color: var(--accent); }
.lv3 .lv-badge { background: rgba(129,199,132,0.2); color: var(--accent-2); }
.lv-text { font-size: 13px; line-height: 1.5; }
.lv-connector {
  text-align: center; padding: 2px 0;
  font-size: 16px; color: var(--muted);
}

/* ── Advanced code card ── */
.adv-card {
  background: var(--code-bg); border-radius: 6px; padding: 14px 16px;
  border-left: 3px solid var(--accent-2); margin: 10px 0;
}
.adv-en { font-size: 14px; color: var(--accent-2); font-style: italic; line-height: 1.6; }
.adv-jp { font-size: 12px; color: var(--muted); margin-top: 6px; }

/* ── Self-evaluation ── */
.self-eval-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 12px; margin: 12px 0;
}
.eval-card {
  background: var(--code-bg); border-radius: 6px; padding: 14px;
  border: 1px solid var(--border);
}
.eval-label { font-size: 12px; font-weight: 700; color: var(--accent-3); margin-bottom: 6px; }
textarea {
  width: 100%; min-height: 80px;
  background: var(--panel-2); color: var(--text);
  border: 1px solid var(--border); border-radius: 4px;
  padding: 8px; font-family: inherit; font-size: 13px; resize: vertical;
}
.understanding-group { display: flex; gap: 10px; flex-wrap: wrap; margin: 12px 0; }
.understanding-group label {
  background: var(--panel-2); padding: 8px 16px; border-radius: 20px;
  cursor: pointer; display: inline-flex; gap: 8px; align-items: center;
  border: 1px solid var(--border); font-size: 13px; transition: border-color 0.15s;
}
.understanding-group label:has(input:checked) { border-color: var(--accent-2); color: var(--accent-2); }
.understanding-group input { accent-color: var(--accent-2); }
.eval-actions { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 14px; }
button.action {
  background: var(--accent-2); color: #000; border: none;
  padding: 8px 18px; border-radius: 4px; cursor: pointer; font-weight: 700;
  font-size: 13px; transition: background 0.15s;
}
button.action:hover { background: #a5d6a7; }
button.action.secondary {
  background: var(--panel-2); color: var(--text); border: 1px solid var(--border);
}

/* ── Slack / Chat messages ── */
.slack-channel-label {
  font-size: 12px; color: var(--muted); margin-bottom: 10px;
  display: flex; align-items: center; gap: 4px;
}
.slack-channel-label::before { content: '#'; font-weight: 700; }
.slack-msg {
  background: var(--code-bg); border-radius: 8px;
  padding: 12px 16px; margin: 10px 0;
  border-left: 3px solid transparent;
}
.slack-msg.p0 { border-left-color: var(--bad); }
.slack-msg.resolved { border-left-color: var(--good); }
.slack-msg .slack-header {
  display: flex; gap: 8px; align-items: baseline; margin-bottom: 6px;
}
.slack-msg .slack-user { font-weight: 700; color: var(--accent-3); font-size: 13px; }
.slack-msg .slack-time { font-size: 11px; color: var(--muted); }
.slack-msg .slack-body { font-size: 13px; line-height: 1.7; }
.slack-msg .slack-body pre {
  background: var(--panel-2); border-radius: 4px; padding: 8px 12px;
  font-size: 12px; margin: 8px 0; border: 1px solid var(--border); white-space: pre-wrap;
}
.slack-thread { margin-left: 28px; padding-left: 12px; border-left: 2px solid var(--border); }

/* ── Email mock ── */
.email-box {
  background: var(--code-bg); border-radius: 8px;
  border: 1px solid var(--border); overflow: hidden; margin: 10px 0;
}
.email-header-block {
  padding: 12px 16px; background: var(--panel-2);
  border-bottom: 1px solid var(--border);
}
.email-field {
  font-size: 12px; display: flex; gap: 8px; margin: 3px 0;
}
.email-field .ef-label { color: var(--muted); min-width: 60px; }
.email-field .ef-value { color: var(--text); font-weight: 600; }
.email-subject { font-size: 15px; font-weight: 700; color: var(--accent); margin-top: 8px; }
.email-body-block {
  padding: 16px; font-size: 13px; line-height: 1.85;
  white-space: pre-wrap; font-family: inherit;
}
.email-sig { border-top: 1px solid var(--border); margin-top: 10px; padding-top: 10px; color: var(--muted); }

/* ── Presentation script ── */
.script-card {
  background: var(--code-bg); border-radius: 8px;
  padding: 20px 24px; margin: 12px 0;
  border-left: 4px solid var(--accent);
  font-size: 15px; line-height: 1.85; font-style: italic; color: var(--text);
}
.script-meta {
  font-size: 11px; color: var(--muted); margin-top: 10px;
  font-style: normal; border-top: 1px solid var(--border); padding-top: 8px;
}
.slide-structure { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin: 12px 0; }
.slide-block {
  background: var(--code-bg); border-radius: 6px; padding: 12px 14px;
  border-top: 3px solid var(--accent-2);
}
.slide-num { font-size: 11px; color: var(--muted); font-weight: 700; margin-bottom: 4px; }
.slide-title { font-size: 13px; font-weight: 700; color: var(--text); }
.slide-body { font-size: 12px; color: var(--muted); margin-top: 4px; }

/* ── Report / Document ── */
.doc-box {
  background: var(--code-bg); border-radius: 8px;
  border: 1px solid var(--border); overflow: hidden; margin: 10px 0;
}
.doc-title-bar {
  padding: 10px 16px; background: var(--panel-2);
  border-bottom: 2px solid var(--accent-2);
  font-weight: 700; font-size: 14px; color: var(--accent-2);
}
.doc-body { padding: 16px; font-size: 13px; line-height: 1.85; white-space: pre-wrap; }
.doc-section { margin: 12px 0; }
.doc-section h4 { color: var(--accent-3); font-size: 13px; margin: 0 0 6px; }

/* ── Negotiation ── */
.nego-table { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin: 14px 0; }
.nego-side {
  padding: 14px 16px; border-radius: 8px; font-size: 13px; line-height: 1.7;
}
.nego-you {
  background: rgba(27,94,32,0.2); border: 1px solid var(--accent-2);
}
.nego-you .nego-label { color: var(--accent-2); }
.nego-them {
  background: rgba(21,101,192,0.15); border: 1px solid var(--accent);
}
.nego-them .nego-label { color: var(--accent); }
.nego-label {
  font-size: 10px; font-weight: 700; text-transform: uppercase;
  letter-spacing: 1px; margin-bottom: 8px; display: block;
}
.nego-exchange { display: flex; flex-direction: column; gap: 0; }
.nego-exchange .speech-bubble { margin: 4px 0; }

/* ── Utility ── */
code {
  background: var(--code-bg); padding: 2px 6px; border-radius: 3px;
  font-family: "JetBrains Mono", Menlo, monospace; font-size: 12px; color: #e1bee7;
}
ul, ol { padding-left: 20px; }
li { margin: 5px 0; font-size: 14px; }
p { font-size: 14px; }
hr { border: none; border-top: 1px solid var(--border); margin: 20px 0; }
strong { color: var(--text); }

/* ── Responsive ── */
@media (max-width: 800px) {
  .layout { grid-template-columns: 1fr; }
  nav.toc { position: static; }
  .notes-grid { grid-template-columns: 1fr; }
  .comparison-card { grid-template-columns: 1fr; }
  .cmp-arrow { display: none; }
}