/* ==========================================================================
   deep-learning-intro-study
   Editorial theme: one teal accent, system fonts, light and dark schemes.
   Every custom class is prefixed with `dl-` and used on docs/index.md.
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. Tokens
   -------------------------------------------------------------------------- */

:root {
  /* Teal palette shared by both schemes. */
  --dl-teal-900: #004d40;
  --dl-teal-800: #00574b;
  --dl-teal-700: #00695c;
  --dl-teal-600: #00796b;
  --dl-teal-300: #5ecdbf;
  --dl-teal-200: #8fe0d5;
  --dl-teal-050: #e0f2f1;

  /* Header and Material buttons: white text on #00695c is 6.6:1. */
  --md-primary-fg-color: var(--dl-teal-700);
  --md-primary-fg-color--light: var(--dl-teal-600);
  --md-primary-fg-color--dark: var(--dl-teal-900);

  /* System font stacks that fall back gracefully for Korean text. */
  --md-text-font-family: -apple-system, BlinkMacSystemFont, "Segoe UI",
    "Apple SD Gothic Neo", "Noto Sans KR", "Malgun Gothic", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  --md-code-font-family: ui-monospace, SFMono-Regular, Menlo, Consolas,
    "Liberation Mono", "Noto Sans Mono CJK KR", monospace;

  --dl-radius: 0.5rem;
  --dl-motion: 160ms ease-out;
}

[data-md-color-scheme="default"] {
  --dl-accent: var(--dl-teal-600);        /* 5.3:1 on white */
  --dl-accent-strong: var(--dl-teal-800); /* 7.4:1 on --dl-accent-soft */
  --dl-accent-soft: var(--dl-teal-050);
  --dl-accent-border: #7fc9bf;
  --dl-surface: #ffffff;
  --dl-surface-alt: #f5f8f8;
  --dl-line: #d8dee0;
  --dl-line-strong: #b8c2c5;
  --dl-muted: #55626b;                    /* 6.4:1 on white */
  --md-typeset-a-color: var(--dl-accent);
  --md-accent-fg-color: var(--dl-accent);
  --md-accent-fg-color--transparent: rgba(0, 121, 107, 0.1);
}

[data-md-color-scheme="slate"] {
  --dl-accent: var(--dl-teal-300);        /* 8.3:1 on slate background */
  --dl-accent-strong: var(--dl-teal-200);
  --dl-accent-soft: rgba(94, 205, 191, 0.14);
  --dl-accent-border: rgba(94, 205, 191, 0.45);
  --dl-surface: #262a33;
  --dl-surface-alt: #1f232b;
  --dl-line: #363c47;
  --dl-line-strong: #4a5160;
  --dl-muted: #aab3bc;
  --md-typeset-a-color: var(--dl-accent);
  --md-accent-fg-color: var(--dl-accent);
  --md-accent-fg-color--transparent: rgba(94, 205, 191, 0.12);
}

/* --------------------------------------------------------------------------
   2. Global typography
   -------------------------------------------------------------------------- */

.md-typeset {
  word-break: keep-all;
  overflow-wrap: anywhere;
}

.md-typeset h1 {
  font-weight: 750;
  letter-spacing: -0.02em;
  color: var(--md-default-fg-color);
}

.md-typeset h2 {
  margin-top: 2.1em;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.md-typeset a {
  text-underline-offset: 0.15em;
}

/* No creator or generator metadata is shown on the learner-facing site. */
.md-footer-meta {
  display: none;
}

.md-typeset a:focus-visible,
.md-typeset .md-button:focus-visible {
  outline: 2px solid var(--dl-accent);
  outline-offset: 2px;
  border-radius: 0.15rem;
}

/* Buttons keep readable contrast in both schemes. */
.md-typeset .md-button {
  color: var(--dl-accent);
  border-color: var(--dl-accent);
  border-radius: var(--dl-radius);
  font-weight: 600;
  transition: background-color var(--dl-motion), color var(--dl-motion),
    border-color var(--dl-motion);
}

.md-typeset .md-button:hover,
.md-typeset .md-button:focus-visible {
  color: var(--dl-accent-strong);
  background-color: var(--dl-accent-soft);
  border-color: var(--dl-accent);
}

.md-typeset .md-button--primary,
.md-typeset .md-button--primary:hover,
.md-typeset .md-button--primary:focus-visible {
  color: #ffffff;
  background-color: var(--dl-teal-700);
  border-color: var(--dl-teal-700);
}

.md-typeset .md-button--primary:hover,
.md-typeset .md-button--primary:focus-visible {
  background-color: var(--dl-teal-800);
  border-color: var(--dl-teal-800);
}

/* Chapter pages: keep the original quote-style path marker. */
.curriculum-path {
  border-left: 0.2rem solid var(--dl-accent);
  padding-left: 1rem;
}

/* --------------------------------------------------------------------------
   3. Homepage layout
   -------------------------------------------------------------------------- */

.dl-home {
  --dl-gap: 1rem;
}

.dl-section {
  margin-top: 3rem;
  padding-top: 0.25rem;
}

.dl-section--closing {
  border-top: 1px solid var(--dl-line);
  padding-top: 1.5rem;
}

.md-typeset .dl-section > h2 {
  margin-top: 0;
  margin-bottom: 0.9rem;
}

/* Hero ------------------------------------------------------------------- */

.dl-hero {
  padding-bottom: 1.75rem;
  border-bottom: 1px solid var(--dl-line);
}

.md-typeset .dl-kicker {
  margin: 0 0 0.4rem;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--dl-accent);
}

.md-typeset .dl-title {
  margin: 0 0 0.9rem;
  font-size: clamp(1.7rem, 4.5vw, 2.35rem);
  line-height: 1.2;
  max-width: 24ch;
}

.md-typeset .dl-title .headerlink {
  display: none;
}

.md-typeset .dl-lede {
  max-width: 44rem;
  font-size: 0.95rem;
  line-height: 1.75;
  color: var(--md-default-fg-color);
}

.md-typeset .dl-meta {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(13rem, 1fr));
  gap: var(--dl-gap);
  margin: 1.4rem 0;
  padding: 0;
}

.md-typeset .dl-meta__item {
  padding: 0.55rem 0 0;
  border-top: 2px solid var(--dl-accent-border);
}

.md-typeset .dl-meta dt {
  margin: 0 0 0.2rem;
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--dl-muted);
}

.md-typeset .dl-meta dd {
  margin: 0;
  font-size: 0.8rem;
  line-height: 1.55;
}

.md-typeset .dl-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 0;
}

.md-typeset .dl-actions .md-button {
  margin: 0;
}

/* Cards ------------------------------------------------------------------ */

.md-typeset .dl-grid {
  display: grid;
  gap: var(--dl-gap);
  grid-template-columns: repeat(auto-fit, minmax(15rem, 1fr));
}

.md-typeset .dl-grid--4 {
  grid-template-columns: repeat(auto-fit, minmax(13.5rem, 1fr));
}

.md-typeset .dl-card,
.md-typeset .dl-phase,
.md-typeset .dl-route {
  margin: 0;
  padding: 1rem 1.1rem;
  background: var(--dl-surface);
  border: 1px solid var(--dl-line);
  border-radius: var(--dl-radius);
  transition: border-color var(--dl-motion);
}

.md-typeset .dl-card:hover,
.md-typeset .dl-phase:hover,
.md-typeset .dl-route:hover {
  border-color: var(--dl-line-strong);
}

.md-typeset .dl-card__title,
.md-typeset .dl-phase__title {
  margin: 0 0 0.5rem;
  font-size: 0.9rem;
  font-weight: 700;
  line-height: 1.35;
}

.md-typeset .dl-card ul,
.md-typeset .dl-phase ul {
  margin: 0;
  padding-left: 1.1rem;
  font-size: 0.78rem;
  line-height: 1.6;
}

.md-typeset .dl-card li,
.md-typeset .dl-phase li {
  margin-bottom: 0.3rem;
}

.md-typeset .dl-card > p:last-child,
.md-typeset .dl-phase > p:last-child {
  margin-bottom: 0;
}

.md-typeset .dl-card--link p {
  font-size: 0.78rem;
  line-height: 1.6;
}

.md-typeset .dl-card--link ul {
  list-style: none;
  padding-left: 0;
}

.md-typeset .dl-card--link li {
  padding: 0.3rem 0;
  border-top: 1px solid var(--dl-line);
}

.md-typeset .dl-card--link li:first-child {
  border-top: 0;
  padding-top: 0;
}

/* Phase cards ------------------------------------------------------------ */

.md-typeset .dl-phase {
  display: flex;
  flex-direction: column;
  border-top: 3px solid var(--dl-accent);
}

.md-typeset .dl-phase__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  margin: 0 0 0.5rem;
}

.md-typeset .dl-phase__num {
  font-family: Georgia, "Times New Roman", "Noto Serif KR", serif;
  font-size: 1.35rem;
  font-weight: 700;
  line-height: 1;
  color: var(--dl-accent);
}

.md-typeset .dl-phase__desc {
  margin: 0 0 0.75rem;
  font-size: 0.76rem;
  line-height: 1.6;
  color: var(--dl-muted);
}

.md-typeset .dl-phase ul {
  margin-top: auto;
  padding-top: 0.6rem;
  border-top: 1px dashed var(--dl-line);
  list-style: none;
  padding-left: 0;
}

/* Tags ------------------------------------------------------------------- */

.md-typeset .dl-tag {
  display: inline-block;
  padding: 0.12rem 0.5rem;
  border: 1px solid var(--dl-line-strong);
  border-radius: 999px;
  font-size: 0.62rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  line-height: 1.5;
  white-space: nowrap;
  color: var(--dl-muted);
  background: var(--dl-surface-alt);
}

.md-typeset .dl-tag--required,
.md-typeset .dl-tag--recombine,
.md-typeset .dl-tag--core {
  color: var(--dl-accent-strong);
  background: var(--dl-accent-soft);
  border-color: var(--dl-accent-border);
}

.md-typeset .dl-tag--exposure {
  color: var(--dl-accent-strong);
  background: transparent;
  border-color: var(--dl-accent);
}

.md-typeset .dl-tag--example {
  color: var(--dl-muted);
  background: transparent;
  border-style: dashed;
}

/* Backbone and branches map --------------------------------------------- */

.md-typeset .dl-map {
  margin: 1.25rem 0 0;
  padding: 1.25rem;
  background: var(--dl-surface-alt);
  border: 1px solid var(--dl-line);
  border-radius: var(--dl-radius);
}

.md-typeset .dl-map__row {
  position: relative;
  margin: 0;
}

.md-typeset .dl-map__row + .dl-map__row {
  margin-top: 2rem;
}

/* Connector between rows: a short vertical rule, no icons. */
.md-typeset .dl-map__row + .dl-map__row::before {
  content: "";
  position: absolute;
  left: 50%;
  top: -2rem;
  width: 2px;
  height: 2rem;
  background: var(--dl-accent-border);
  transform: translateX(-50%);
}

.md-typeset .dl-map__row--backbone,
.md-typeset .dl-map__row--recombine {
  padding: 0.9rem 1rem;
  background: var(--dl-surface);
  border: 1px solid var(--dl-accent-border);
  border-radius: var(--dl-radius);
}

.md-typeset .dl-map__row--backbone {
  border-left: 4px solid var(--dl-accent);
}

.md-typeset .dl-map__row--recombine {
  border-left: 4px solid var(--dl-accent);
  border-style: solid;
}

.md-typeset .dl-map__row--branches {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(12rem, 1fr));
  gap: var(--dl-gap);
}

.md-typeset .dl-branch {
  padding: 0.9rem 1rem;
  background: var(--dl-surface);
  border: 1px solid var(--dl-line);
  border-radius: var(--dl-radius);
}

.md-typeset .dl-map__label {
  margin: 0 0 0.5rem;
  font-size: 0.66rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--dl-muted);
}

.md-typeset .dl-map__nodes {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin: 0;
}

.md-typeset .dl-branch .dl-map__nodes {
  flex-direction: column;
  align-items: stretch;
}

.md-typeset .dl-node {
  display: inline-block;
  padding: 0.3rem 0.65rem;
  font-size: 0.74rem;
  font-weight: 600;
  line-height: 1.4;
  color: var(--md-default-fg-color);
  background: var(--dl-surface);
  border: 1px solid var(--dl-line-strong);
  border-radius: 0.35rem;
  text-decoration: none;
  transition: border-color var(--dl-motion), background-color var(--dl-motion),
    color var(--dl-motion);
}

.md-typeset .dl-node:hover,
.md-typeset .dl-node:focus-visible {
  color: var(--dl-accent-strong);
  background: var(--dl-accent-soft);
  border-color: var(--dl-accent);
}

/* Depth labels ----------------------------------------------------------- */

.md-typeset .dl-depth {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(15rem, 1fr));
  gap: var(--dl-gap);
  margin: 1rem 0 0;
}

.md-typeset .dl-depth__item {
  padding: 0.9rem 1rem;
  background: var(--dl-surface);
  border: 1px solid var(--dl-line);
  border-radius: var(--dl-radius);
}

.md-typeset .dl-depth dt {
  margin: 0 0 0.5rem;
}

.md-typeset .dl-depth dd {
  margin: 0;
  font-size: 0.78rem;
  line-height: 1.6;
}

/* Reading routes --------------------------------------------------------- */

.md-typeset .dl-routes {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(17rem, 1fr));
  gap: var(--dl-gap);
  margin-top: 1rem;
}

.md-typeset .dl-route__name {
  margin: 0 0 0.3rem;
  font-size: 0.88rem;
  font-weight: 700;
}

.md-typeset .dl-route__desc {
  margin: 0 0 0.7rem;
  font-size: 0.76rem;
  line-height: 1.6;
  color: var(--dl-muted);
}

.md-typeset .dl-route__steps {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.3rem;
  margin: 0;
}

.md-typeset .dl-step {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 1.9rem;
  height: 1.9rem;
  padding: 0 0.45rem;
  font-size: 0.74rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  color: var(--dl-accent-strong);
  background: var(--dl-accent-soft);
  border: 1px solid var(--dl-accent-border);
  border-radius: 999px;
  text-decoration: none;
  transition: background-color var(--dl-motion), border-color var(--dl-motion);
}

.md-typeset a.dl-step:hover,
.md-typeset a.dl-step:focus-visible {
  border-color: var(--dl-accent);
  background: var(--dl-surface);
}

.md-typeset .dl-step--more,
.md-typeset .dl-step--or {
  color: var(--dl-muted);
  background: transparent;
  border-color: transparent;
  font-weight: 600;
}

/* Recurring questions ---------------------------------------------------- */

.md-typeset .dl-questions {
  margin: 0.75rem 0 0;
  padding-left: 0;
  list-style: none;
  counter-reset: dl-question;
}

.md-typeset .dl-questions li {
  position: relative;
  margin: 0;
  padding: 0.65rem 0 0.65rem 2.4rem;
  border-top: 1px solid var(--dl-line);
  font-size: 0.8rem;
  line-height: 1.65;
  counter-increment: dl-question;
}

.md-typeset .dl-questions li:last-child {
  border-bottom: 1px solid var(--dl-line);
}

.md-typeset .dl-questions li::before {
  content: counter(dl-question);
  position: absolute;
  left: 0;
  top: 0.75rem;
  width: 1.6rem;
  height: 1.6rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--dl-accent-strong);
  background: var(--dl-accent-soft);
  border: 1px solid var(--dl-accent-border);
  border-radius: 999px;
}

/* --------------------------------------------------------------------------
   4. Responsive and motion preferences
   -------------------------------------------------------------------------- */

@media screen and (max-width: 44.9375em) {
  .dl-section {
    margin-top: 2.25rem;
  }

  .md-typeset .dl-map {
    padding: 0.9rem;
  }

  .md-typeset .dl-map__row + .dl-map__row {
    margin-top: 1.5rem;
  }

  .md-typeset .dl-map__row + .dl-map__row::before {
    top: -1.5rem;
    height: 1.5rem;
  }

  .md-typeset .dl-actions .md-button {
    flex: 1 1 100%;
    text-align: center;
  }
}

@media (prefers-reduced-motion: reduce) {
  .md-typeset .dl-card,
  .md-typeset .dl-phase,
  .md-typeset .dl-route,
  .md-typeset .dl-node,
  .md-typeset .dl-step,
  .md-typeset .md-button {
    transition: none;
  }
}

@media print {
  .md-typeset .dl-card,
  .md-typeset .dl-phase,
  .md-typeset .dl-route,
  .md-typeset .dl-map,
  .md-typeset .dl-depth__item {
    break-inside: avoid;
    border-color: #999999;
  }
}