/* Hallmark · study hub · editorial · technical · course catalog */
:root {
  --color-bg: #f7f5f0;
  --color-surface: #ffffff;
  --color-ink: #1a1a1a;
  --color-ink-muted: #5c5a55;
  --color-line: #e2ddd3;
  --color-accent: #2f5d50;
  --color-accent-soft: #e8f0ed;
  --color-focus: #1a1a1a;
  --font-body: "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  --font-display: "Noto Serif SC", "Songti SC", "SimSun", Georgia, serif;
  --font-mono: "JetBrains Mono", "SF Mono", ui-monospace, monospace;
  --measure: 48rem;
  --page-max: 92rem;
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 1rem;
  --space-4: 1.5rem;
  --space-5: 2.5rem;
  --space-6: 4rem;
  --radius: 0.75rem;
  --shadow: 0 1px 0 color-mix(in srgb, var(--color-ink) 6%, transparent);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  overflow-x: clip;
}

body {
  min-height: 100vh;
  background: var(--color-bg);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: 1.0625rem;
  line-height: 1.65;
}

a {
  color: var(--color-accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
}

a:hover {
  color: var(--color-ink);
}

a:focus-visible,
button:focus-visible,
input:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 3px;
}

.site {
  width: min(100% - 2.5rem, var(--page-max));
  margin-inline: auto;
  padding-block: var(--space-5) var(--space-6);
  min-width: 0;
}

.site-header {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-3);
  padding-bottom: var(--space-4);
  border-bottom: 1px solid var(--color-line);
  margin-bottom: var(--space-5);
}

.wordmark {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 600;
  letter-spacing: 0;
  color: var(--color-ink);
  text-decoration: none;
}

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  font-size: 0.9375rem;
}

.nav a {
  color: var(--color-ink-muted);
  text-decoration: none;
}

.nav a:hover,
.nav a[aria-current="page"] {
  color: var(--color-ink);
}

.hero {
  max-width: var(--measure);
  margin-bottom: var(--space-4);
}

.hero h1 {
  margin: 0 0 var(--space-3);
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 2.75rem);
  font-weight: 600;
  line-height: 1.15;
  overflow-wrap: break-word;
  min-width: 0;
}

.hero p {
  margin: 0;
  color: var(--color-ink-muted);
  font-size: 1.125rem;
}

.catalog-toolbar {
  display: grid;
  gap: var(--space-2);
  margin-bottom: var(--space-4);
}

.search-field {
  display: grid;
  gap: var(--space-2);
  max-width: 32rem;
}

.search-label {
  font-size: 0.875rem;
  color: var(--color-ink-muted);
}

.search-field input {
  width: 100%;
  min-width: 0;
  padding: 0.85rem 1rem;
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
  background: var(--color-surface);
  color: var(--color-ink);
  font: inherit;
  box-shadow: var(--shadow);
}

.search-field input::placeholder {
  color: color-mix(in srgb, var(--color-ink-muted) 80%, transparent);
}

.catalog-status {
  margin: 0;
  font-size: 0.875rem;
  color: var(--color-ink-muted);
}

.course-grid,
.note-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(100%, 18rem), 1fr));
  gap: var(--space-3);
}

.course-item[hidden] {
  display: none;
}

.course-card,
.note-card {
  display: grid;
  gap: var(--space-2);
  min-height: 11rem;
  padding: var(--space-4);
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  text-decoration: none;
  color: inherit;
  transition: border-color 160ms ease, box-shadow 160ms ease;
}

.course-card:hover,
.note-card:hover {
  border-color: color-mix(in srgb, var(--color-accent) 35%, var(--color-line));
  box-shadow: 0 8px 24px color-mix(in srgb, var(--color-ink) 6%, transparent);
}

.course-tag {
  display: inline-flex;
  width: fit-content;
  padding: 0.2rem 0.55rem;
  border-radius: 999px;
  background: var(--color-accent-soft);
  color: var(--color-accent);
  font-size: 0.75rem;
  font-weight: 600;
}

.course-card h2,
.note-card h2 {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 600;
  overflow-wrap: break-word;
  min-width: 0;
}

.course-card p,
.note-card p {
  margin: 0;
  color: var(--color-ink-muted);
  font-size: 0.975rem;
}

.catalog-empty {
  margin: var(--space-5) 0 0;
  color: var(--color-ink-muted);
}

.meta {
  font-size: 0.8125rem;
  color: var(--color-ink-muted);
}

.layout-note {
  display: grid;
  grid-template-columns: minmax(0, 17rem) minmax(0, 1fr);
  gap: var(--space-5);
  align-items: start;
}

.layout-note.is-toc-collapsed {
  grid-template-columns: 2.75rem minmax(0, 1fr);
  gap: var(--space-3);
}

.toc {
  position: sticky;
  top: var(--space-3);
  z-index: 20;
  display: flex;
  align-items: stretch;
  min-width: 0;
  max-height: calc(100vh - 2 * var(--space-3));
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.toc-edge {
  flex: 0 0 2.75rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  margin: 0;
  padding: var(--space-3) 0;
  border: 0;
  border-right: 1px solid var(--color-line);
  background: color-mix(in srgb, var(--color-bg) 55%, var(--color-surface));
  color: var(--color-ink-muted);
  cursor: pointer;
  font: inherit;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  writing-mode: vertical-rl;
  text-orientation: mixed;
  transform: rotate(180deg);
}

.toc-edge:hover {
  color: var(--color-accent);
  background: var(--color-accent-soft);
}

.toc-edge:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: -2px;
}

.toc-edge-mark {
  display: inline-block;
  width: 0.42rem;
  height: 0.42rem;
  border-right: 1.5px solid currentColor;
  border-bottom: 1.5px solid currentColor;
  transform: rotate(-45deg);
  transition: transform 160ms ease;
}

.toc.is-collapsed .toc-edge-mark {
  transform: rotate(135deg);
}

.toc-nav {
  flex: 1 1 auto;
  min-width: 0;
  padding: var(--space-3);
  overflow-y: auto;
}

.toc-heading {
  margin: 0 0 var(--space-3);
  padding-bottom: var(--space-2);
  border-bottom: 1px solid var(--color-line);
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--color-ink-muted);
}

.toc.is-collapsed .toc-nav {
  display: none;
}

.toc-backdrop {
  display: none;
}

.toc ol {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 0.15rem;
}

.toc li {
  margin: 0;
}

.toc a {
  display: block;
  padding: 0.45rem 0.65rem;
  border-radius: calc(var(--radius) - 0.15rem);
  border-left: 2px solid transparent;
  color: var(--color-ink-muted);
  text-decoration: none;
  font-size: 0.875rem;
  line-height: 1.4;
  transition: background-color 140ms ease, color 140ms ease, border-color 140ms ease;
}

.toc a:hover {
  background: var(--color-accent-soft);
  color: var(--color-accent);
  text-decoration: none;
}

@media (max-width: 860px) {
  .layout-note,
  .layout-note.is-toc-collapsed {
    grid-template-columns: minmax(0, 1fr);
    gap: 0;
  }

  /* 收起时只保留左下角按钮，避免挡住表格首列 */
  .toc {
    position: fixed;
    top: auto;
    left: 0;
    bottom: 5.5rem;
    z-index: 40;
    width: auto;
    max-height: none;
    display: block;
    background: transparent;
    border: none;
    border-radius: 0;
    box-shadow: none;
    overflow: visible;
  }

  .toc-edge {
    writing-mode: horizontal-tb;
    text-orientation: mixed;
    transform: none;
    flex: none;
    width: auto;
    min-width: 2.75rem;
    min-height: 2.75rem;
    padding: 0.6rem 0.75rem;
    border: 1px solid var(--color-line);
    border-left: 0;
    border-radius: 0 var(--radius) var(--radius) 0;
    background: var(--color-surface);
    box-shadow: var(--shadow);
    font-size: 0.8125rem;
    letter-spacing: 0;
    gap: 0.4rem;
  }

  .toc-edge-mark {
    transform: rotate(-45deg);
  }

  .toc.is-open .toc-edge-mark,
  .toc.is-collapsed .toc-edge-mark {
    transform: rotate(135deg);
  }

  .toc:not(.is-open) .toc-nav {
    display: none;
  }

  .toc.is-open {
    top: 0;
    left: 0;
    bottom: 0;
    width: min(18.5rem, calc(100vw - 3rem));
    display: flex;
    align-items: stretch;
    background: var(--color-surface);
    border: 1px solid var(--color-line);
    border-left: 0;
    border-radius: 0 var(--radius) var(--radius) 0;
    box-shadow: var(--shadow);
    overflow: hidden;
  }

  .toc.is-open .toc-edge {
    border-right: 1px solid var(--color-line);
    border-radius: 0;
    box-shadow: none;
  }

  .toc.is-open .toc-nav {
    display: block;
    flex: 1 1 auto;
    overflow-y: auto;
  }

  .toc-backdrop {
    display: block;
    position: fixed;
    inset: 0;
    z-index: 35;
    border: 0;
    margin: 0;
    padding: 0;
    background: color-mix(in srgb, var(--color-ink) 28%, transparent);
    opacity: 0;
    pointer-events: none;
    transition: opacity 180ms ease;
  }

  .toc-backdrop.is-visible {
    opacity: 1;
    pointer-events: auto;
  }
}

@media (prefers-reduced-motion: reduce) {
  .toc-edge-mark,
  .toc-backdrop,
  .toc a {
    transition: none;
  }
}


.article {
  max-width: var(--measure);
}

.article h1 {
  margin: 0 0 var(--space-3);
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 3vw, 2.25rem);
  line-height: 1.2;
  overflow-wrap: break-word;
  min-width: 0;
}

.article h2 {
  margin: var(--space-5) 0 var(--space-3);
  font-size: 1.25rem;
}

.article p,
.article li {
  color: var(--color-ink);
}

.article code,
.kicker {
  font-family: var(--font-mono);
  font-size: 0.9em;
}

.site-footer {
  margin-top: var(--space-6);
  padding-top: var(--space-4);
  border-top: 1px solid var(--color-line);
  color: var(--color-ink-muted);
  font-size: 0.875rem;
}

@media (prefers-reduced-motion: reduce) {
  .course-card,
  .note-card {
    transition: none;
  }
}


/* Note / course article surfaces (shared with homepage tokens) */
.note-hero {
  margin: 0 0 var(--space-4);
  padding: var(--space-4);
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.note-hero h1 {
  margin: 0 0 var(--space-3);
}

.note-lead {
  font-size: 1.05rem;
  color: var(--color-ink);
}

.note-article .callout {
  margin: var(--space-3) 0;
  padding: var(--space-3) var(--space-4);
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.note-article .callout.df {
  background: var(--color-accent-soft);
  border-color: color-mix(in srgb, var(--color-accent) 28%, var(--color-line));
}

.note-article .callout.own {
  background: color-mix(in srgb, var(--color-accent-soft) 70%, white);
  border-color: color-mix(in srgb, var(--color-accent) 22%, var(--color-line));
}

.note-article .callout.warn {
  background: #fff7ed;
  border-color: #fcd34d;
}

.note-article .tag {
  display: inline-block;
  margin-right: var(--space-2);
  padding: 0.12rem 0.45rem;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 600;
  background: var(--color-accent-soft);
  color: var(--color-accent);
}

.note-article .tag.df,
.note-article .tag.own,
.note-article .tag.mix {
  background: var(--color-accent-soft);
  color: var(--color-accent);
}

.note-article .grid2 {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-3);
  margin: var(--space-3) 0;
}

@media (max-width: 860px) {
  .note-article .grid2 {
    grid-template-columns: minmax(0, 1fr);
  }
}

.note-article .card {
  padding: var(--space-3) var(--space-4);
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.note-article .card h3 {
  margin-top: 0;
}

.note-article .table-wrap {
  display: block;
  width: 100%;
  max-width: 100%;
  min-width: 0;
  overflow-x: auto;
  overflow-y: hidden;
  -webkit-overflow-scrolling: touch;
  overscroll-behavior-x: contain;
  margin: var(--space-3) 0 var(--space-4);
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
  background: var(--color-surface);
  box-shadow: var(--shadow);
}

.note-article table {
  width: max-content;
  min-width: 100%;
  max-width: none;
  border-collapse: collapse;
  font-size: 0.92rem;
}

@media (max-width: 860px) {
  .note-article .table-wrap {
    /* leave room so left TOC button doesn't cover first cells */
    scroll-padding-inline: 3rem;
  }

  .note-article {
    min-width: 0;
    max-width: 100%;
  }

  .layout-note {
    min-width: 0;
    width: 100%;
  }
}

.note-article th,
.note-article td {
  padding: 0.6rem 0.65rem;
  border-bottom: 1px solid var(--color-line);
  text-align: left;
  vertical-align: top;
}

.note-article th {
  color: var(--color-ink-muted);
  font-weight: 600;
  background: color-mix(in srgb, var(--color-bg) 70%, white);
  white-space: nowrap;
}

.note-article tr:last-child td {
  border-bottom: none;
}

.note-article pre,
.note-article .flow {
  margin: var(--space-3) 0 var(--space-4);
  padding: 0.95rem 1.05rem;
  overflow-x: auto;
  border-radius: var(--radius);
  border: 1px solid color-mix(in srgb, var(--color-ink) 82%, transparent);
  background: #1a1a1a;
  color: #f0eee8;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  line-height: 1.5;
  white-space: pre;
}

.note-article pre code {
  background: transparent;
  border: none;
  padding: 0;
  color: inherit;
  font-size: inherit;
}

.note-article .mermaid-caption {
  margin: 0.15rem 0 0.55rem;
  color: var(--color-ink-muted);
  font-size: 0.92rem;
  font-weight: 600;
}

.note-article .mermaid-wrap {
  margin: var(--space-2) 0 var(--space-4);
  padding: 1.15rem 1.25rem;
  overflow-x: auto;
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.note-article .mermaid-wrap .mermaid {
  display: block;
  min-width: 45rem;
  background: var(--color-surface);
}

.note-article .mermaid-wrap svg {
  max-width: none !important;
  height: auto !important;
}

.note-article ul.compact li {
  margin: 0.28rem 0;
}

.note-article .tocdoc {
  columns: 2;
  gap: 1.4rem;
  font-size: 0.88rem;
  color: var(--color-ink-muted);
  line-height: 1.55;
}

.note-article .tocdoc .l1 {
  font-weight: 600;
  color: var(--color-ink);
  list-style: none;
  margin-left: 0;
}

.note-article .tocdoc .l2 {
  margin-left: 1rem;
}

.note-article .muted {
  color: var(--color-ink-muted);
}

.note-article .note-end {
  margin-top: var(--space-5);
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
  background: var(--color-surface);
  color: var(--color-ink-muted);
  font-size: 0.875rem;
}

.toc a[aria-current="true"] {
  background: var(--color-accent-soft);
  color: var(--color-accent);
  border-left-color: var(--color-accent);
  font-weight: 600;
}

.back-home {
  margin-top: var(--space-5);
  padding-top: var(--space-4);
  border-top: 1px solid var(--color-line);
  font-size: 0.9375rem;
}

.layout-note {
  align-items: start;
}

.note-article {
  max-width: none;
  min-width: 0;
}

.note-article > .note-hero + *,
.note-article > .callout:first-of-type {
  /* keep flow */
}