:root {
  color-scheme: light;
  --bg: #f6f4ee;
  --ink: #17202a;
  --muted: #66717d;
  --panel: #fffdf7;
  --line: rgba(23, 32, 42, 0.12);
  --accent: #1f6f78;
  --accent-strong: #124e55;
  --warm: #b66b2d;
  --good: #27764c;
  --warn: #a44235;
  --soft: #e7f2ee;
  --shadow: 0 16px 40px rgba(23, 32, 42, 0.08);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--ink);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.5;
}

a {
  color: var(--accent-strong);
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.18em;
}

pre,
code {
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
}

pre {
  white-space: pre-wrap;
  padding: 0.9rem;
  border: 1px solid var(--line);
  background: #f3f7f5;
  border-radius: 8px;
}

.shell {
  width: min(1220px, calc(100% - 2rem));
  margin: 0 auto;
  padding: 1.2rem 0 4rem;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  color: var(--ink);
  font-weight: 900;
  text-decoration: none;
}

.brand-mark {
  width: 2rem;
  height: 2rem;
  display: grid;
  place-items: center;
  border-radius: 8px;
  background: #d6efe6;
  color: #1f6f78;
}

.nav {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  flex-wrap: wrap;
}

.nav a,
.nav button,
.button {
  appearance: none;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 0.55rem 0.75rem;
  background: rgba(255, 255, 255, 0.74);
  color: var(--ink);
  font: inherit;
  font-weight: 800;
  text-decoration: none;
  cursor: pointer;
}

.button.primary,
.nav a.primary {
  background: var(--accent-strong);
  color: #fff;
  border-color: transparent;
}

.button.danger {
  background: var(--warn);
  color: #fff;
}

.page-head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 1rem;
  margin: 1.25rem 0 1rem;
}

.page-head h1,
.panel h1,
.panel h2,
.panel h3 {
  margin: 0;
  line-height: 1.08;
}

.page-head h1 {
  font-size: clamp(2rem, 4vw, 3.5rem);
  letter-spacing: 0;
}

.eyebrow {
  margin: 0 0 0.25rem;
  color: var(--accent-strong);
  font-size: 0.78rem;
  text-transform: uppercase;
  font-weight: 900;
  letter-spacing: 0.08em;
}

.lede,
.muted,
.meta {
  color: var(--muted);
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1rem;
}

.grid.two {
  grid-template-columns: minmax(0, 1.35fr) minmax(280px, 0.65fr);
}

.panel,
.card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.panel {
  padding: 1rem;
}

.card {
  padding: 0.9rem;
}

.stack {
  display: grid;
  gap: 1rem;
}

.stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 0.75rem;
}

.stat {
  padding: 0.8rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fbfaf5;
}

.stat strong {
  display: block;
  font-size: 1.7rem;
  line-height: 1;
}

.track-card {
  display: grid;
  gap: 0.7rem;
}

.progress {
  height: 0.75rem;
  border: 1px solid var(--line);
  background: #eef0ea;
  border-radius: 999px;
  overflow: hidden;
}

.progress span {
  display: block;
  height: 100%;
  background: var(--accent);
}

.pill-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.pill {
  display: inline-flex;
  align-items: center;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.22rem 0.5rem;
  background: #f7faf7;
  color: var(--muted);
  font-size: 0.85rem;
  font-weight: 800;
}

.pill.shaky {
  color: var(--warn);
  background: rgba(164, 66, 53, 0.08);
}

.pill.mastered {
  color: var(--good);
  background: rgba(39, 118, 76, 0.1);
}

.review-card {
  display: grid;
  gap: 1rem;
}

.prompt {
  font-size: 1.05rem;
}

.prompt pre {
  margin: 0.65rem 0 0;
}

label {
  display: grid;
  gap: 0.35rem;
  color: var(--muted);
  font-weight: 800;
}

input,
textarea,
select {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 0.65rem 0.75rem;
  background: #fff;
  color: var(--ink);
  font: inherit;
}

textarea {
  min-height: 8rem;
  resize: vertical;
}

.form-grid {
  display: grid;
  gap: 0.75rem;
}

.button-row,
.filters {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
}

.answer-panel {
  border-left: 4px solid var(--accent);
  padding-left: 0.85rem;
}

.hidden-policy {
  padding: 0.75rem;
  border: 1px dashed rgba(31, 111, 120, 0.38);
  background: var(--soft);
  border-radius: 8px;
}

.table-wrap {
  overflow-x: auto;
}

table {
  width: 100%;
  border-collapse: collapse;
}

th,
td {
  padding: 0.55rem;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

th {
  color: var(--muted);
  font-size: 0.84rem;
  text-transform: uppercase;
}

.tree {
  display: grid;
  gap: 1rem;
}

.unit {
  border-top: 1px solid var(--line);
  padding-top: 0.9rem;
}

.topic-list {
  display: grid;
  gap: 0.45rem;
  margin-top: 0.6rem;
}

.topic-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 0.75rem;
  align-items: center;
  padding: 0.65rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fbfaf5;
}

.login-page {
  display: grid;
  place-items: center;
  padding: 1rem;
}

.login-card {
  width: min(420px, 100%);
  padding: 1.2rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: var(--shadow);
}

.form-error,
.notice {
  padding: 0.7rem 0.8rem;
  border-radius: 8px;
}

.form-error {
  color: var(--warn);
  background: rgba(164, 66, 53, 0.1);
}

.notice {
  color: var(--good);
  background: rgba(39, 118, 76, 0.1);
}

@media (max-width: 760px) {
  .topbar,
  .page-head,
  .grid.two,
  .topic-row {
    display: grid;
    grid-template-columns: 1fr;
  }

  .nav {
    width: 100%;
  }
}