/* ===== Pre-Study Page ===== */
.study-toc {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 32px;
}
.study-toc a {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 16px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  font-size: 14px;
  color: var(--text-soft);
  font-weight: 600;
  transition: border-color 0.15s ease, background 0.15s ease;
}
.study-toc a:hover {
  border-color: var(--accent);
  background: var(--bg-card-hover);
  color: var(--text);
}
.toc-num {
  font-family: 'JetBrains Mono', monospace;
  color: var(--accent);
  font-size: 12px;
}

.study-section {
  padding: 80px 0;
  border-top: 1px solid var(--border);
}
.ch-head {
  margin-bottom: 48px;
}
.ch-num {
  font-family: 'JetBrains Mono', monospace;
  color: var(--accent);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.16em;
  margin-bottom: 8px;
}
.ch-head h2 {
  font-size: 36px;
  letter-spacing: -0.02em;
  margin: 0;
  font-weight: 800;
}

.study-h3 {
  font-size: 24px;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin: 0 0 24px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border);
}
.hl {
  color: var(--accent);
}

/* ===== Card grids ===== */
.study-grid-4 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  margin-bottom: 32px;
}
.study-grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
  margin-bottom: 32px;
}
.study-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 24px;
  transition: border-color 0.2s ease, transform 0.2s ease;
}
.study-card:hover {
  border-color: var(--border-strong);
  transform: translateY(-2px);
}
.study-card.accent-card {
  border-color: var(--accent);
  background: linear-gradient(180deg, var(--bg-card), rgba(217, 119, 87, 0.05));
}
.study-icon {
  font-size: 32px;
  margin-bottom: 10px;
}
.study-card-title {
  font-size: 17px;
  font-weight: 700;
  margin-bottom: 6px;
  letter-spacing: -0.01em;
}
.study-card p {
  font-size: 14px;
  color: var(--text-mute);
  margin: 0 0 12px;
  line-height: 1.6;
}
.study-examples {
  font-size: 12px;
  color: var(--text-mute);
  font-family: 'JetBrains Mono', monospace;
  border-top: 1px dashed var(--border);
  padding-top: 10px;
  margin-top: 6px;
}
.study-link {
  display: inline-block;
  font-size: 13px;
  color: var(--accent);
  font-weight: 600;
  margin-right: 12px;
}
.study-link:hover { color: var(--accent-strong); }

/* ===== Big quote ===== */
.big-quote {
  background: var(--bg-card);
  border-left: 4px solid var(--accent);
  border-radius: 12px;
  padding: 36px 40px;
  margin: 32px 0;
  text-align: center;
}
.quote-main {
  font-size: 28px;
  font-weight: 700;
  margin: 0 0 12px;
  letter-spacing: -0.02em;
  line-height: 1.4;
}
.quote-main em {
  color: var(--accent);
  font-style: normal;
}
.quote-sub {
  color: var(--text-mute);
  font-size: 15px;
  margin: 0;
  line-height: 1.7;
}

/* ===== Compare table ===== */
.compare-wrap {
  overflow-x: auto;
}
.study-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  font-size: 14.5px;
}
.study-table th,
.study-table td {
  padding: 14px 18px;
  text-align: left;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}
.study-table thead th {
  background: var(--bg-alt);
  font-weight: 700;
  font-size: 13px;
  color: var(--text);
  letter-spacing: 0.02em;
}
.study-table tbody tr:last-child td { border-bottom: none; }
.study-table .row-label {
  font-weight: 700;
  color: var(--text-mute);
  font-size: 13px;
  width: 130px;
}
.study-table td.bad,
.study-table .bad { color: #fca5a5; }
.study-table td.good,
.study-table .good { color: #6ee7b7; }
.bad-text { color: #fca5a5; }
.good-text { color: #6ee7b7; }
.study-table code {
  font-family: 'JetBrains Mono', monospace;
  background: rgba(217, 119, 87, 0.1);
  color: var(--accent-strong);
  padding: 2px 8px;
  border-radius: 6px;
  font-size: 13px;
}

/* ===== VS layout ===== */
.vs-layout {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 16px;
  align-items: stretch;
  margin: 24px 0 32px;
}
.vs-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 24px;
}
.vs-card.bad { border-color: rgba(248, 113, 113, 0.3); }
.vs-card.good { border-color: rgba(110, 231, 183, 0.3); }
.vs-title {
  font-weight: 700;
  font-size: 16px;
  margin-bottom: 14px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border);
}
.vs-card.bad .vs-title { color: #fca5a5; }
.vs-card.good .vs-title { color: #6ee7b7; }
.vs-card ul {
  margin: 0;
  padding-left: 20px;
  color: var(--text-soft);
  font-size: 14px;
  line-height: 1.9;
}
.vs-divider {
  align-self: center;
  font-family: 'JetBrains Mono', monospace;
  color: var(--text-mute);
  font-weight: 800;
  font-size: 18px;
}

/* ===== Flow ===== */
.flow-section {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 28px;
  margin: 24px 0;
}
.flow-label-bad,
.flow-label-good {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.16em;
  margin-bottom: 12px;
  text-transform: uppercase;
}
.flow-label-bad { color: #fca5a5; }
.flow-label-good { color: #6ee7b7; }
.flow-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}
.flow-step {
  flex: 1;
  min-width: 140px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px 16px;
  font-size: 13.5px;
  font-weight: 600;
  text-align: center;
  color: var(--text-soft);
}
.flow-step.accent {
  border-color: var(--accent);
  background: rgba(217, 119, 87, 0.05);
  color: var(--text);
}
.flow-arrow {
  color: var(--text-mute);
  font-weight: 700;
  font-size: 18px;
}
.flow-arrow.accent-arrow { color: var(--accent); }

/* ===== Stack flow (Ch3) ===== */
.stack-flow {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  margin: 24px 0 32px;
}
.stack-box {
  width: 100%;
  max-width: 480px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 20px 24px;
  text-align: center;
}
.stack-box.accent {
  border-color: var(--accent);
  background: linear-gradient(180deg, var(--bg-card), rgba(217, 119, 87, 0.06));
}
.stack-label {
  font-size: 12px;
  color: var(--text-mute);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  margin-bottom: 4px;
}
.stack-text {
  font-size: 17px;
  font-weight: 700;
}
.stack-arrow {
  color: var(--text-mute);
  font-size: 22px;
  font-weight: 700;
}

/* ===== Folder row ===== */
.folder-row {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  align-items: center;
  justify-content: center;
  margin: 24px 0 12px;
}
.folder-card {
  background: var(--bg-card);
  border: 2px solid var(--c, var(--border));
  border-radius: 14px;
  padding: 20px 28px;
  min-width: 200px;
  text-align: center;
}
.folder-name {
  font-family: 'JetBrains Mono', monospace;
  font-size: 14px;
  font-weight: 700;
  color: var(--c);
  margin-bottom: 6px;
}
.folder-desc {
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
}
.folder-sub {
  font-size: 12px;
  color: var(--text-mute);
  margin-top: 4px;
}
.folder-arrow {
  color: var(--text-mute);
  font-size: 22px;
  font-weight: 700;
}
.centerline {
  text-align: center;
  font-size: 18px;
  font-weight: 700;
  color: var(--text);
  margin: 16px 0 32px;
}

/* ===== Markdown compare (Ch3) ===== */
.md-compare {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-bottom: 32px;
}
.md-bad,
.md-good {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 24px;
}
.md-bad { border-color: rgba(248, 113, 113, 0.3); }
.md-good { border-color: rgba(110, 231, 183, 0.3); }
.md-title {
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: 16px;
}
.md-bad .md-title { color: #fca5a5; }
.md-good .md-title { color: #6ee7b7; }
.md-flow {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
  margin: 20px 0;
  font-size: 16px;
  font-weight: 700;
}
.md-flow span {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 16px;
}
.md-flow .hl-box {
  border-color: var(--accent);
  color: var(--accent-strong);
}
.md-flow b {
  color: var(--text-mute);
  font-size: 18px;
}
.md-warn,
.md-ok {
  text-align: center;
  font-size: 13.5px;
  font-weight: 600;
  margin: 0;
}
.md-warn { color: #fca5a5; }
.md-ok { color: #6ee7b7; }

/* ===== Skill cmd ===== */
.skill-cmd {
  font-family: 'JetBrains Mono', monospace;
  font-size: 16px;
  font-weight: 700;
  color: var(--accent-strong);
  margin-bottom: 8px;
}

/* ===== Install steps ===== */
.install-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 28px 32px;
}
.install-steps {
  margin: 0;
  padding-left: 24px;
  color: var(--text-soft);
  font-size: 15px;
  line-height: 2;
}
.install-steps code {
  font-family: 'JetBrains Mono', monospace;
  background: var(--bg);
  border: 1px solid var(--border);
  padding: 2px 8px;
  border-radius: 6px;
  font-size: 13px;
  color: var(--accent-strong);
}
.study-end-note {
  margin-top: 24px;
  padding: 16px 20px;
  background: var(--bg-card);
  border-left: 3px solid var(--accent);
  border-radius: 8px;
  color: var(--text-soft);
  font-size: 14.5px;
}
.study-end-note a {
  color: var(--accent);
  font-weight: 600;
}

/* ===== Responsive ===== */
@media (max-width: 900px) {
  .study-section { padding: 56px 0; }
  .ch-head h2 { font-size: 30px; }
  .study-grid-4 { grid-template-columns: 1fr 1fr; }
  .vs-layout { grid-template-columns: 1fr; }
  .vs-divider { transform: rotate(90deg); padding: 8px 0; }
  .md-compare { grid-template-columns: 1fr; }
}

@media (max-width: 640px) {
  .study-section { padding: 44px 0; }
  .ch-head { margin-bottom: 32px; }
  .ch-head h2 { font-size: 24px; }
  .study-h3 { font-size: 19px; margin-bottom: 18px; }

  /* TOC scrollable */
  .study-toc {
    overflow-x: auto;
    flex-wrap: nowrap;
    margin-left: -16px;
    margin-right: -16px;
    padding: 0 16px 8px;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
  }
  .study-toc::-webkit-scrollbar { display: none; }
  .study-toc a { flex-shrink: 0; padding: 10px 14px; }

  /* Grids → 1 column */
  .study-grid-4,
  .study-grid-3 { grid-template-columns: 1fr; gap: 12px; }
  .study-card { padding: 20px; }

  /* Quotes */
  .big-quote { padding: 24px 22px; margin: 24px 0; }
  .quote-main { font-size: 22px; }
  .quote-sub { font-size: 14px; }

  /* Tables — horizontal scroll */
  .compare-wrap {
    overflow-x: auto;
    margin-left: -16px;
    margin-right: -16px;
    padding: 0 16px;
    -webkit-overflow-scrolling: touch;
  }
  .study-table { min-width: 540px; font-size: 13.5px; }
  .study-table th, .study-table td { padding: 10px 12px; }

  /* Stack flow */
  .stack-box { padding: 16px 20px; }
  .stack-text { font-size: 15px; }

  /* Folder row stacks vertically */
  .folder-row { flex-direction: column; }
  .folder-arrow { transform: rotate(90deg); }
  .folder-card { width: 100%; padding: 16px 20px; }
  .centerline { font-size: 16px; }

  /* Markdown compare */
  .md-flow { font-size: 14px; gap: 8px; }
  .md-flow span { padding: 8px 12px; }

  /* VS layout */
  .vs-card { padding: 20px; }

  /* Flow row */
  .flow-section { padding: 22px; }
  .flow-row { flex-direction: column; align-items: stretch; }
  .flow-arrow { transform: rotate(90deg); }
  .flow-step { width: 100%; }

  /* Install */
  .install-card { padding: 22px 24px; }
  .install-steps { font-size: 14.5px; line-height: 1.9; }
}