/* ═══════════════════════════════════════════════════════════
   Learn page — extends base style.css
   ═══════════════════════════════════════════════════════════ */

.learn-hero {
  background:
    radial-gradient(1000px 400px at 50% 0%, rgba(14,124,134,.28), transparent 65%),
    linear-gradient(180deg, var(--navy-800) 0%, var(--navy-900) 100%);
  color: var(--white);
  padding: 70px 24px 60px;
  text-align: center;
}
.learn-hero-inner {
  max-width: 900px;
  margin: 0 auto;
  display: block;
}

.timeline-wrap { margin-top: 48px; }
.timeline-svg { width: 100%; max-width: 900px; height: auto; }

.timeline-caption {
  margin-top: 16px;
  font-size: 13.5px;
  color: rgba(255,255,255,.6);
  max-width: 620px;
  margin-left: auto; margin-right: auto;
  line-height: 1.6;
}
.timeline-caption strong { color: var(--teal-400); }

.learn-section { padding: 80px 24px; }
.learn-section.alt-bg {
  background: linear-gradient(180deg, var(--bg-50) 0%, #eef4f9 100%);
}
.learn-container { max-width: 1080px; margin: 0 auto; }

.section-head {
  text-align: center;
  margin-bottom: 48px;
}
.step-num {
  display: inline-block;
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  font-weight: 700;
  color: var(--teal-600);
  background: var(--teal-100);
  padding: 4px 12px;
  border-radius: 20px;
  letter-spacing: 1px;
  margin-bottom: 16px;
}
.section-title-lg {
  font-size: clamp(24px, 4vw, 34px);
  font-weight: 800;
  color: var(--navy-800);
  letter-spacing: -.02em;
  margin-bottom: 12px;
}
.section-lead {
  font-size: 16px;
  color: var(--ink-700);
  max-width: 680px;
  margin: 0 auto;
  line-height: 1.7;
}
.section-lead code {
  background: var(--bg-100);
  padding: 2px 6px;
  border-radius: 4px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 13.5px;
  color: var(--teal-600);
}
.section-lead em { color: var(--navy-800); font-style: normal; font-weight: 600; }

/* Anatomy */
.anatomy-diagram {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  box-shadow: var(--shadow-sm);
  margin-bottom: 40px;
  overflow-x: auto;
}
.anatomy-line {
  font-family: 'JetBrains Mono', monospace;
  font-size: 15px;
  padding: 16px 0;
  white-space: nowrap;
  line-height: 2.2;
}
.tok { padding: 6px 4px; border-radius: 4px; transition: all .15s; }
.tok:hover { transform: translateY(-2px); box-shadow: 0 4px 12px rgba(0,0,0,.1); }
.tok.seg-name { background: #e3ecf7; color: var(--navy-800); font-weight: 700; padding: 6px 12px; }
.tok.field    { background: #fff4d9; color: #8a5a00; }
.tok.comp     { background: #d9f2ef; color: #0d6b5c; }
.tok.delim    { color: var(--ink-300); font-weight: 400; padding: 6px 2px; }

.anatomy-labels {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  margin-top: 24px;
  padding-top: 24px;
  border-top: 1px dashed var(--border);
}
.anatomy-label {
  display: flex; align-items: flex-start; gap: 10px;
  font-size: 13px;
}
.anatomy-label .muted { color: var(--ink-500); font-size: 12px; }
.anatomy-label strong { color: var(--navy-800); }
.dot {
  width: 12px; height: 12px; border-radius: 3px; flex-shrink: 0; margin-top: 4px;
}
.dot-seg   { background: #e3ecf7; border: 1px solid var(--navy-600); }
.dot-field { background: #fff4d9; border: 1px solid #c99400; }
.dot-comp  { background: #d9f2ef; border: 1px solid #0d6b5c; }

/* Concept cards */
.concept-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 20px;
}
.concept-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px 22px;
  position: relative;
  transition: all .2s;
}
.concept-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
  border-color: var(--teal-400);
}
.concept-num {
  position: absolute; top: -14px; left: 22px;
  width: 30px; height: 30px;
  background: linear-gradient(135deg, var(--navy-800), var(--teal-600));
  color: var(--white);
  border-radius: 8px;
  display: flex; align-items: center; justify-content: center;
  font-weight: 800; font-size: 14px;
  box-shadow: 0 4px 10px rgba(10,37,64,.25);
}
.concept-card h3 {
  font-size: 16px; font-weight: 700;
  color: var(--navy-800); margin: 8px 0 10px;
}
.concept-card p {
  font-size: 13.5px; color: var(--ink-700); line-height: 1.65;
}
.concept-card code {
  background: var(--bg-100);
  padding: 1px 5px; border-radius: 3px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 12.5px; color: var(--teal-600);
}

/* Segments */
.segment-tabs {
  display: flex; gap: 8px; justify-content: center;
  flex-wrap: wrap; margin-bottom: 28px;
}
.seg-tab {
  padding: 10px 22px;
  background: var(--white);
  border: 1.5px solid var(--border);
  border-radius: 10px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 14px; font-weight: 700;
  color: var(--ink-700);
  cursor: pointer;
  transition: all .15s;
}
.seg-tab:hover { border-color: var(--teal-500); color: var(--teal-600); }
.seg-tab.active {
  background: linear-gradient(135deg, var(--navy-800), var(--teal-600));
  color: var(--white);
  border-color: transparent;
  box-shadow: 0 6px 20px rgba(10,37,64,.25);
}

.segment-panel {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  box-shadow: var(--shadow-md);
  min-height: 300px;
  animation: fadeIn .25s ease;
}
@keyframes fadeIn { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }

.segment-panel h3 {
  color: var(--navy-800);
  font-size: 20px; font-weight: 800;
  margin-bottom: 6px;
  letter-spacing: -.01em;
}
.segment-panel .seg-full {
  color: var(--ink-500);
  font-size: 13.5px;
  margin-bottom: 20px;
}
.segment-panel pre {
  background: var(--code-bg);
  color: var(--code-fg);
  padding: 18px 22px;
  border-radius: var(--radius-sm);
  font-family: 'JetBrains Mono', monospace;
  font-size: 13px;
  overflow-x: auto;
  margin-bottom: 22px;
  line-height: 1.7;
}
.field-table {
  width: 100%; border-collapse: collapse; font-size: 13px;
}
.field-table th {
  background: var(--bg-50);
  text-align: left;
  padding: 10px 12px;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: .6px;
  color: var(--ink-500);
  border-bottom: 1px solid var(--border);
}
.field-table td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}
.field-table tr:last-child td { border-bottom: 0; }
.field-table .f-pos {
  font-family: 'JetBrains Mono', monospace;
  color: var(--teal-600);
  font-weight: 700;
}
.field-table .f-name { font-weight: 600; color: var(--navy-800); }
.field-table .f-desc { color: var(--ink-700); }

/* Delimiters */
.delim-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 20px;
  margin-bottom: 32px;
}
.delim-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px 22px;
  text-align: center;
  transition: all .2s;
}
.delim-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
  border-color: var(--teal-400);
}
.delim-symbol {
  font-family: 'JetBrains Mono', monospace;
  font-size: 48px;
  font-weight: 700;
  background: linear-gradient(135deg, var(--navy-800), var(--teal-600));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  line-height: 1.1;
  margin-bottom: 12px;
}
.delim-name {
  font-weight: 700; font-size: 14px;
  color: var(--navy-800); margin-bottom: 8px;
}
.delim-desc {
  font-size: 12.5px; color: var(--ink-700);
  line-height: 1.6; margin-bottom: 12px;
}
.delim-desc code {
  background: var(--bg-100);
  padding: 1px 5px; border-radius: 3px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 11.5px; color: var(--teal-600);
}
.delim-example {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  color: var(--ink-700);
  background: var(--bg-50);
  border: 1px dashed var(--border);
  padding: 8px 10px;
  border-radius: 6px;
  word-break: break-all;
}

.callout {
  border-radius: var(--radius-sm);
  padding: 16px 20px;
  font-size: 14px;
  line-height: 1.6;
  border-left: 4px solid;
}
.callout strong { color: var(--navy-800); display: block; margin-bottom: 4px; }
.callout-info { background: var(--info-bg); border-color: var(--info); color: var(--ink-700); }
.callout-warn { background: var(--warn-bg); border-color: var(--warn); color: var(--ink-700); }
.callout code {
  background: rgba(255,255,255,.6);
  padding: 1px 6px; border-radius: 3px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 13px;
}

/* Positions */
.positions-diagram {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: var(--shadow-sm);
  margin-bottom: 28px;
  overflow-x: auto;
}
.pos-row {
  font-family: 'JetBrains Mono', monospace;
  font-size: 14px;
  display: flex;
  flex-wrap: nowrap;
  white-space: nowrap;
  padding: 12px 0;
  line-height: 1.5;
}
.pos-cell {
  padding: 8px 6px;
  border-radius: 4px;
  flex-shrink: 0;
}
.pos-name { background: var(--navy-800); color: var(--white); font-weight: 700; padding: 8px 12px; }
.pos-delim { color: var(--ink-300); padding: 8px 2px; }
.pos-num {
  background: var(--teal-100);
  color: var(--teal-600);
  font-weight: 700;
  padding: 8px 10px;
  border: 1px dashed var(--teal-500);
}
.pos-value { background: var(--bg-50); color: var(--ink-900); border: 1px solid var(--border); }

.pos-labels {
  display: flex; flex-wrap: wrap; gap: 12px;
  margin-top: 20px; padding-top: 20px;
  border-top: 1px dashed var(--border);
}
.pos-label {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 13px; color: var(--ink-700);
}
.pos-chip {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  font-weight: 700;
  background: var(--navy-800);
  color: var(--white);
  padding: 3px 10px;
  border-radius: 4px;
}

/* Walkthrough */
.walkthrough {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 24px;
}
.walkthrough-code {
  background: var(--code-bg);
  border-radius: var(--radius);
  padding: 18px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 12.5px;
  color: var(--code-fg);
  box-shadow: var(--shadow-md);
  overflow: hidden;
}
.wt-line {
  padding: 8px 10px;
  border-radius: 6px;
  cursor: pointer;
  white-space: pre;
  overflow-x: auto;
  transition: background .15s;
  border-left: 3px solid transparent;
  margin-bottom: 2px;
}
.wt-line:hover { background: rgba(255,255,255,.06); }
.wt-line.active {
  background: rgba(18,163,163,.18);
  border-left-color: var(--teal-400);
}
.wt-seg { color: #7ee0d6; font-weight: 700; }

.walkthrough-explain {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px 24px;
  box-shadow: var(--shadow-sm);
  min-height: 300px;
}
.wt-placeholder {
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  height: 100%; text-align: center;
  color: var(--ink-500); font-size: 13.5px;
  gap: 12px;
}
.wt-icon { font-size: 32px; opacity: .4; }

.wt-content h3 {
  color: var(--navy-800);
  font-size: 17px; font-weight: 800;
  margin-bottom: 10px;
  font-family: 'JetBrains Mono', monospace;
  letter-spacing: .5px;
}
.wt-content .wt-role {
  font-size: 12.5px;
  text-transform: uppercase;
  color: var(--teal-600);
  font-weight: 700;
  letter-spacing: 1px;
  margin-bottom: 14px;
}
.wt-content p {
  font-size: 13.5px;
  color: var(--ink-700);
  line-height: 1.7;
  margin-bottom: 12px;
}
.wt-fields {
  display: flex; flex-direction: column; gap: 8px;
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px dashed var(--border);
}
.wt-field {
  display: flex; align-items: baseline; gap: 10px;
  font-size: 12.5px;
}
.wt-field .tag {
  font-family: 'JetBrains Mono', monospace;
  font-weight: 700;
  color: var(--teal-600);
  background: var(--teal-100);
  padding: 2px 8px;
  border-radius: 4px;
  flex-shrink: 0;
  font-size: 11.5px;
}
.wt-field .txt { color: var(--ink-700); }

/* Message types */
.mtype-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 18px;
}
.mtype-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px 22px;
  transition: all .2s;
  position: relative;
  overflow: hidden;
}
.mtype-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 4px; height: 100%;
  background: linear-gradient(180deg, var(--teal-500), var(--gold-500));
}
.mtype-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
  border-color: var(--teal-400);
}
.mtype-code {
  font-family: 'JetBrains Mono', monospace;
  font-size: 22px;
  font-weight: 800;
  color: var(--navy-800);
  letter-spacing: 1px;
  margin-bottom: 6px;
}
.mtype-full {
  font-size: 13px;
  font-weight: 600;
  color: var(--ink-700);
  margin-bottom: 12px;
  line-height: 1.4;
}
.mtype-events {
  font-family: 'JetBrains Mono', monospace;
  font-size: 11.5px;
  color: var(--teal-600);
  background: var(--teal-100);
  padding: 6px 10px;
  border-radius: 6px;
  margin-bottom: 10px;
  display: inline-block;
  font-weight: 600;
}
.mtype-use {
  font-size: 12.5px;
  color: var(--ink-500);
  margin-top: 4px;
}

/* Pitfalls */
.pitfall-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 18px;
}
.pitfall {
  display: flex;
  gap: 16px;
  background: var(--white);
  border: 1px solid var(--border);
  border-left: 4px solid var(--warn);
  border-radius: var(--radius-sm);
  padding: 20px;
  transition: all .15s;
}
.pitfall:hover {
  box-shadow: var(--shadow-md);
  transform: translateX(2px);
}
.pitfall-icon {
  font-size: 22px;
  flex-shrink: 0;
  color: var(--warn);
}
.pitfall h4 {
  font-size: 14px;
  font-weight: 700;
  color: var(--navy-800);
  margin-bottom: 6px;
}
.pitfall p {
  font-size: 13px;
  color: var(--ink-700);
  line-height: 1.65;
}
.pitfall code {
  background: var(--bg-100);
  padding: 1px 6px; border-radius: 3px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  color: var(--teal-600);
}
.pitfall em { color: var(--navy-800); font-style: normal; font-weight: 600; }

/* CTA */
.learn-cta {
  background:
    radial-gradient(800px 300px at 50% 50%, rgba(18,163,163,.25), transparent 70%),
    linear-gradient(135deg, var(--navy-800), var(--navy-900));
  color: var(--white);
  padding: 70px 24px;
  text-align: center;
}
.learn-cta-inner { max-width: 600px; margin: 0 auto; }
.learn-cta h2 {
  font-size: 32px; font-weight: 800;
  letter-spacing: -.02em;
  margin-bottom: 12px;
}
.learn-cta p {
  font-size: 15.5px;
  color: rgba(255,255,255,.7);
  margin-bottom: 28px;
}

@media (max-width: 800px) {
  .walkthrough { grid-template-columns: 1fr; }
  .learn-hero { padding: 50px 20px 40px; }
  .learn-section { padding: 60px 20px; }
  .segment-panel { padding: 22px 18px; }
  .anatomy-diagram { padding: 20px 16px; }
  .positions-diagram { padding: 20px 16px; }
  .pos-row { font-size: 12px; }
  .learn-cta h2 { font-size: 24px; }
}