:root {
  --paper: #fbfaf7;
  --surface: #ffffff;
  --ink: #263238;
  --muted: #66747b;
  --line: #ddd8ce;
  --teal: #2f7d75;
  --teal-soft: #dcefeb;
  --coral: #c95f4d;
  --coral-soft: #f6dfda;
  --gold: #9f742c;
  --gold-soft: #f5ead2;
  --plum: #665a91;
  --plum-soft: #e9e5f3;
  --shadow: 0 18px 48px rgba(38, 50, 56, 0.1);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.65;
}

button,
input {
  font: inherit;
}

button {
  cursor: pointer;
}

.shell {
  width: min(1180px, calc(100% - 32px));
  margin: 0 auto;
}

.app-header {
  background:
    linear-gradient(90deg, rgba(47, 125, 117, 0.13), rgba(201, 95, 77, 0.08)),
    var(--paper);
  border-bottom: 1px solid var(--line);
}

.header-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(280px, 420px);
  gap: 28px;
  align-items: stretch;
  padding: 44px 0 24px;
}

.intro-panel,
.flow-panel,
.rail-section,
.note-card,
.lesson-card,
.practice-row,
.table-wrap,
.glossary-card,
.summary-strip {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.intro-panel {
  padding: 32px;
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--teal);
  font-size: 0.82rem;
  font-weight: 800;
  letter-spacing: 0;
}

h1,
h2,
h3,
h4,
p {
  overflow-wrap: anywhere;
}

h1 {
  margin: 0;
  font-size: clamp(2.15rem, 6vw, 4.5rem);
  line-height: 1.04;
  letter-spacing: 0;
}

h2 {
  margin: 0 0 12px;
  font-size: 1.55rem;
  line-height: 1.25;
  letter-spacing: 0;
}

h3 {
  margin: 0 0 10px;
  font-size: 1.1rem;
  line-height: 1.35;
  letter-spacing: 0;
}

h4 {
  margin: 0 0 8px;
  font-size: 0.98rem;
  letter-spacing: 0;
}

p {
  margin: 0;
}

.intro-copy {
  max-width: 680px;
  margin-top: 14px;
  color: var(--muted);
  font-size: 1.08rem;
}

.quick-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  margin-top: 28px;
}

.quick-stats div {
  min-height: 82px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fffcf6;
}

.quick-stats strong {
  display: block;
  font-size: 1.8rem;
  line-height: 1;
}

.quick-stats span {
  display: block;
  margin-top: 6px;
  color: var(--muted);
  font-size: 0.9rem;
}

.flow-panel {
  display: grid;
  align-content: center;
  grid-template-columns: 1fr;
  gap: 12px;
  padding: 24px;
}

.flow-node {
  min-height: 54px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 8px;
  font-weight: 800;
}

.flow-node.core {
  background: var(--teal-soft);
  color: #1f605a;
}

.flow-node.air {
  background: var(--gold-soft);
  color: var(--gold);
}

.flow-node.resist {
  background: var(--plum-soft);
  color: var(--plum);
}

.flow-node.voice {
  background: var(--coral-soft);
  color: var(--coral);
}

.flow-line {
  width: 2px;
  height: 18px;
  margin: 0 auto;
  background: var(--line);
}

.top-nav {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(251, 250, 247, 0.94);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(14px);
}

.nav-scroll {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding: 12px 0;
  scrollbar-width: none;
}

.nav-scroll::-webkit-scrollbar {
  display: none;
}

.nav-tab {
  flex: 0 0 auto;
  min-width: 80px;
  min-height: 42px;
  padding: 8px 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  color: var(--muted);
  font-weight: 800;
}

.nav-tab.is-active {
  background: var(--ink);
  border-color: var(--ink);
  color: var(--surface);
}

.main-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 310px;
  gap: 22px;
  padding: 26px 0 56px;
}

.content-stage {
  min-width: 0;
}

.view {
  display: grid;
  gap: 18px;
}

.section-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  gap: 16px;
  margin-bottom: 2px;
}

.section-head p {
  max-width: 740px;
  color: var(--muted);
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.lesson-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.note-card,
.lesson-card,
.glossary-card,
.summary-strip {
  padding: 20px;
}

.lesson-card {
  display: grid;
  gap: 14px;
}

.lesson-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.pill {
  display: inline-flex;
  align-items: center;
  min-height: 30px;
  padding: 4px 10px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #fffcf6;
  color: var(--muted);
  font-size: 0.84rem;
  font-weight: 800;
}

.pill.teal {
  background: var(--teal-soft);
  color: #1f605a;
}

.pill.coral {
  background: var(--coral-soft);
  color: var(--coral);
}

.pill.gold {
  background: var(--gold-soft);
  color: var(--gold);
}

.pill.plum {
  background: var(--plum-soft);
  color: var(--plum);
}

.lesson-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.primary-action,
.secondary-action,
.reset-action {
  min-height: 42px;
  padding: 8px 13px;
  border-radius: 8px;
  font-weight: 800;
}

.primary-action {
  border: 1px solid var(--ink);
  background: var(--ink);
  color: var(--surface);
}

.secondary-action,
.reset-action {
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink);
}

.stack {
  display: grid;
  gap: 12px;
}

.accordion {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  overflow: hidden;
}

.accordion summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  min-height: 56px;
  padding: 14px 16px;
  cursor: pointer;
  font-weight: 900;
  list-style: none;
}

.accordion summary::-webkit-details-marker {
  display: none;
}

.accordion summary::after {
  content: "+";
  flex: 0 0 auto;
  width: 28px;
  height: 28px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--paper);
  color: var(--muted);
}

.accordion[open] summary::after {
  content: "-";
}

.accordion-body {
  display: grid;
  gap: 12px;
  padding: 0 16px 16px;
  color: var(--muted);
}

.accordion-body ul,
.note-card ul,
.practice-row ul {
  margin: 0;
  padding-left: 1.2em;
}

.accordion-body li,
.note-card li,
.practice-row li {
  margin: 4px 0;
}

.keyline {
  border-left: 4px solid var(--teal);
  padding: 14px 16px;
  background: #f7fbf8;
  border-radius: 8px;
}

.practice-list {
  display: grid;
  gap: 12px;
}

.practice-row {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  gap: 12px;
  align-items: start;
  padding: 16px;
  box-shadow: none;
}

.practice-row input[type="checkbox"] {
  width: 22px;
  height: 22px;
  margin-top: 3px;
  accent-color: var(--teal);
}

.practice-row.done {
  border-color: rgba(47, 125, 117, 0.55);
  background: #f3faf7;
}

.practice-time {
  min-width: 64px;
  padding: 4px 8px;
  border-radius: 8px;
  background: var(--gold-soft);
  color: var(--gold);
  text-align: center;
  font-weight: 900;
  font-size: 0.86rem;
}

.progress-bar {
  height: 10px;
  overflow: hidden;
  border-radius: 999px;
  background: #e7e1d7;
}

.progress-bar span {
  display: block;
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, var(--teal), var(--coral));
  transition: width 180ms ease;
}

.table-wrap {
  overflow-x: auto;
  box-shadow: none;
}

table {
  width: 100%;
  min-width: 720px;
  border-collapse: collapse;
  background: var(--surface);
}

th,
td {
  padding: 13px 14px;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

th {
  background: #f4efe5;
  color: var(--ink);
  font-size: 0.9rem;
}

tr:last-child td {
  border-bottom: 0;
}

.glossary-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.side-rail {
  position: sticky;
  top: 82px;
  display: grid;
  align-content: start;
  gap: 14px;
  min-width: 0;
}

.rail-section {
  padding: 18px;
  box-shadow: none;
}

.mini-list {
  display: grid;
  gap: 8px;
  margin-top: 12px;
}

.mini-list div {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  padding: 8px 0;
  border-bottom: 1px solid var(--line);
  color: var(--muted);
}

.mini-list div:last-child {
  border-bottom: 0;
}

.empty-state {
  padding: 26px;
  border: 1px dashed var(--line);
  border-radius: 8px;
  color: var(--muted);
  background: var(--surface);
}

@media (max-width: 930px) {
  .header-grid,
  .main-grid,
  .lesson-grid,
  .card-grid,
  .glossary-grid {
    grid-template-columns: 1fr;
  }

  .side-rail {
    position: static;
    order: -1;
  }
}

@media (max-width: 640px) {
  .shell {
    width: min(100% - 22px, 1180px);
  }

  .header-grid {
    padding-top: 24px;
  }

  .intro-panel,
  .flow-panel,
  .note-card,
  .lesson-card,
  .summary-strip {
    padding: 16px;
  }

  .quick-stats {
    grid-template-columns: 1fr;
  }

  .section-head {
    display: grid;
  }

  .practice-row {
    grid-template-columns: auto minmax(0, 1fr);
  }

  .practice-time {
    grid-column: 2;
    width: fit-content;
  }
}