/* =======================================================================
 * Site-wide custom styles.
 *
 * Sections:
 *   1. Brand tokens (colour + typography)
 *   2. Typography overrides
 *   3. Brand colour → links, focus rings, theme accents
 *   4. Homepage hero
 *   5. Vertical timeline
 *   6. Year dividers
 *   7. Fade-up animation (respects prefers-reduced-motion)
 *   8. Giscus comments block
 * ======================================================================= */

/* ----- 1. Brand tokens ------------------------------------------------- */

@import url("https://fonts.googleapis.com/css2?family=Fraunces:ital,opsz,wght@0,9..144,500;0,9..144,600;0,9..144,700;1,9..144,500&family=Inter:wght@400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap");

:root {
  /* Oxidised purple. Change this single value to rebrand the whole site. */
  --kb-primary: #6B3FA0;
  --kb-primary-contrast: #ffffff;
  --kb-primary-soft: #efe7f7;
  --kb-primary-soft-border: #d9c5ec;
  --kb-primary-dark: #52307f;

  /* Font stacks */
  --kb-font-display: "Fraunces", Georgia, "Times New Roman", serif;
  --kb-font-body:    "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --kb-font-mono:    "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

html[data-theme="dark"] {
  --kb-primary:         #b38bdd;
  --kb-primary-contrast: #1a1020;
  --kb-primary-soft:    #2a1a3c;
  --kb-primary-soft-border: #4a315f;
  --kb-primary-dark:    #d8b9f2;
}

/* ----- 2. Typography --------------------------------------------------- */

html, body {
  font-family: var(--kb-font-body);
}

h1, h2, h3, h4, h5, h6,
.bd-header .navbar-brand,
.bd-sidebar .bd-sidebar-title {
  font-family: var(--kb-font-display);
  font-weight: 600;
  letter-spacing: -0.005em;
}

h1 { font-weight: 700; letter-spacing: -0.015em; }

code, kbd, samp, pre,
.highlight pre,
.highlight code,
.cell_input pre,
.cell_output pre {
  font-family: var(--kb-font-mono);
  font-variant-ligatures: none;
}

/* ----- 3. Brand colour accents ---------------------------------------- */

/* Override the PyData / Sphinx Book theme primary accent variable. */
:root {
  --pst-color-primary:       var(--kb-primary);
  --pst-color-primary-hover: var(--kb-primary-dark);
  --pst-color-link:          var(--kb-primary);
  --pst-color-link-hover:    var(--kb-primary-dark);
}
html[data-theme="dark"] {
  --pst-color-primary:       var(--kb-primary);
  --pst-color-primary-hover: var(--kb-primary-dark);
  --pst-color-link:          var(--kb-primary);
  --pst-color-link-hover:    var(--kb-primary-dark);
}

a:focus-visible,
button:focus-visible,
[role="button"]:focus-visible {
  outline: 2px solid var(--kb-primary);
  outline-offset: 2px;
  border-radius: 3px;
}

/* ----- 4. Homepage hero ---------------------------------------------- */

/* The markdown `# What I'm learning` renders normally as the page H1 above
 * the hero. We lift it so it reads as part of the hero block. */
.bd-article > section > h1:first-child {
  font-size: clamp(2rem, 4.5vw, 3rem);
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: -0.02em;
  margin: 0.5rem 0 1rem;
}

.kb-hero {
  display: grid;
  grid-template-columns: 1.3fr 1fr;
  gap: 2rem;
  align-items: center;
  max-width: 1100px;
  margin: 0.25rem auto 2.5rem;
  padding: 0 0 2rem;
  border-bottom: 1px solid var(--pst-color-border, #dee2e6);
}

.kb-hero p {
  font-size: 1.12rem;
  color: var(--pst-color-text-muted, #6c757d);
  line-height: 1.55;
  margin: 0;
  max-width: 44ch;
}

.kb-hero-art {
  display: flex;
  justify-content: flex-end;
}

.kb-hero-art img,
.kb-hero-art svg {
  width: 100%;
  max-width: 340px;
  height: auto;
}

@media (max-width: 768px) {
  .kb-hero {
    grid-template-columns: 1fr;
    gap: 1.25rem;
    text-align: center;
  }
  .kb-hero-art { justify-content: center; }
}

/* ----- 5. Vertical timeline ----------------------------------------- */

.kb-timeline {
  position: relative;
  list-style: none;
  max-width: 1100px;
  margin: 0 auto 3rem;
  padding: 1rem 0;
}

.kb-timeline::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  width: 3px;
  background: var(--pst-color-border, #dee2e6);
  transform: translateX(-50%);
  border-radius: 3px;
}

.kb-entry {
  position: relative;
  width: 50%;
  padding: 0.75rem 2.5rem;
  box-sizing: border-box;
}

.kb-entry--left  { left: 0;   text-align: right; }
.kb-entry--right { left: 50%; text-align: left;  }

/* Dot on the centre line. */
.kb-entry::before {
  content: "";
  position: absolute;
  top: 1.5rem;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--kb-primary);
  border: 3px solid var(--pst-color-background, #fff);
  z-index: 1;
  box-shadow: 0 0 0 1px var(--pst-color-border, #dee2e6);
}

.kb-entry--left::before  { right: -8px; }
.kb-entry--right::before { left: -8px; }

/* Card — deliberately no hover effect (requested). */
.kb-card {
  display: block;
  background: var(--pst-color-on-background, #fff);
  border: 1px solid var(--pst-color-border, #dee2e6);
  border-radius: 10px;
  padding: 1rem 1.25rem;
  text-decoration: none !important;
  color: inherit !important;
}

.kb-date {
  display: inline-block;
  font-family: var(--kb-font-mono);
  font-size: 0.76rem;
  font-weight: 600;
  color: var(--kb-primary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-right: 0.4rem;
}

.kb-title {
  font-family: var(--kb-font-display);
  font-size: 1.12rem;
  font-weight: 600;
  margin: 0.3rem 0 0.35rem;
  color: var(--pst-color-text-base, #212529);
  line-height: 1.3;
}

.kb-desc {
  font-size: 0.92rem;
  color: var(--pst-color-text-muted, #6c757d);
  margin: 0;
  line-height: 1.5;
}

.kb-tag {
  display: inline-block;
  font-family: var(--kb-font-body);
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  padding: 0.15rem 0.55rem;
  border-radius: 999px;
  vertical-align: 2px;
}

.kb-tag-ai     { background: var(--kb-primary-soft); color: var(--kb-primary-dark); }
.kb-tag-ml     { background: #dbeafe; color: #1e40af; }
.kb-tag-maths  { background: #fff3cd; color: #8a6d0b; }
.kb-tag-paper  { background: #e2d9f3; color: #59359a; }
.kb-tag-note   { background: #e6f4ea; color: #1e6b3a; }

.kb-entry--right .kb-tag { margin-left: 0.4rem; }
.kb-entry--left  .kb-tag { margin-right: 0.4rem; }

html[data-theme="dark"] .kb-card {
  background: var(--pst-color-surface, #222832);
  border-color: var(--pst-color-border, #3c4554);
}
html[data-theme="dark"] .kb-entry::before {
  border-color: var(--pst-color-background, #14181f);
}
html[data-theme="dark"] .kb-tag-ml    { background: #1e3a5f; color: #93c5fd; }
html[data-theme="dark"] .kb-tag-maths { background: #4a3a0a; color: #ffd966; }
html[data-theme="dark"] .kb-tag-paper { background: #3a2a5c; color: #c8a2ff; }
html[data-theme="dark"] .kb-tag-note  { background: #1e4530; color: #9ddcae; }

/* ----- 6. Year dividers ---------------------------------------------
 * The homepage uses real top-level H2s ("## 2026") so they appear in the
 * right-hand "On this page" nav. We target them structurally (scoped to
 * the intro page) and style them as sticky pills in the brand colour. */

#what-im-learning > section > h2 {
  display: block;
  width: fit-content;
  margin: 2.25rem auto 1rem;
  padding: 0.3rem 1.15rem;
  position: sticky;
  top: 4.25rem;            /* clears the fixed page header */
  z-index: 2;
  background: var(--pst-color-background, #fff);
  border: 2px solid var(--kb-primary);
  border-radius: 999px;
  border-bottom: 2px solid var(--kb-primary);   /* override theme's bottom rule */
  text-align: center;
  font-family: var(--kb-font-display);
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--kb-primary);
}

#what-im-learning > section > h2 > a.headerlink {
  display: none;   /* hide the '#' anchor on year pills for visual calm */
}

/* ----- 7. Fade-up animation ----------------------------------------- */

.kb-entry {
  opacity: 0;
  transform: translateY(18px);
  transition:
    opacity 0.5s cubic-bezier(0.2, 0.6, 0.2, 1),
    transform 0.5s cubic-bezier(0.2, 0.6, 0.2, 1);
}

.kb-entry.kb-in-view {
  opacity: 1;
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  .kb-entry {
    opacity: 1 !important;
    transform: none !important;
    transition: none !important;
  }
}

/* ----- 8. Mobile timeline ------------------------------------------- */

@media (max-width: 768px) {
  .kb-timeline::before { left: 20px; }

  .kb-entry,
  .kb-entry--left,
  .kb-entry--right {
    width: 100%;
    left: 0;
    padding-left: 48px;
    padding-right: 1rem;
    text-align: left;
  }

  .kb-entry::before,
  .kb-entry--left::before,
  .kb-entry--right::before {
    left: 12px;
    right: auto;
  }

  .kb-entry--left .kb-tag { margin-left: 0.4rem; margin-right: 0; }

  .kb-year { top: 4rem; }
}

/* ----- 9. Giscus comments section ----------------------------------- */

.kb-comments {
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--pst-color-border, #dee2e6);
}
.kb-comments h2 {
  font-family: var(--kb-font-display);
  font-size: 1.2rem;
  font-weight: 600;
  margin: 0 0 0.35rem;
}
.kb-comments-intro {
  font-size: 0.9rem;
  color: var(--pst-color-text-muted, #6c757d);
  margin: 0 0 1rem;
}