/*
  Spacing/alignment informed by:
  - 8pt grid (UCLA DS, Design Systems): 8/16/24/32/40/48
  - USWDS: headings closer to their content than prior section;
    readable measure; left-aligned running text
  - Academic RG examples (Imperial CSML, Bath AI): plain schedule tables,
    when/where first, calm hierarchy, accent color used sparingly
*/

:root {
  --s1: 0.5rem;   /* 8 */
  --s2: 1rem;     /* 16 */
  --s3: 1.5rem;   /* 24 */
  --s4: 2rem;     /* 32 */
  --s5: 2.5rem;   /* 40 */
  --s6: 3rem;     /* 48 */

  --teal: #0c8590;
  --teal-deep: #064850;
  --brown: #2f1d12;
  --amber: #c96a1a;
  --gold: #e2b14a;
  --cream: #fff7ec;
  --cream-2: #e7d4b8;
  --ink: #1a1410;
  --muted: #5c4634;

  --font: "IBM Plex Sans", "Segoe UI", sans-serif;
  --serif: "Source Serif 4", Georgia, serif;
  --width: 45rem;
  --label: 5rem;

  --page-bg: #000;
  --page-fg: var(--cream);
  --link: var(--gold);
  --link-hover: #ffe29a;
  --heading: var(--gold);
  --rule: var(--gold);
  --hairline: rgba(255, 247, 236, 0.16);
  --row-hover: rgba(255, 247, 236, 0.04);
  --toggle-track: #161616;
  --toggle-border: #3d3d3d;
  --toggle-knob: #fff7ec;
  --toggle-icon: #c96a1a;
}

html[data-theme="light"] {
  --page-bg: #f4f7f6;
  --page-fg: var(--ink);
  --link: var(--teal-deep);
  --link-hover: var(--amber);
  --heading: var(--brown);
  --rule: #c9a24a;
  --hairline: rgba(47, 29, 18, 0.14);
  --row-hover: rgba(12, 133, 144, 0.05);
  --toggle-track: #d9ebe8;
  --toggle-border: #9ebfbb;
  --toggle-knob: #fff;
  --toggle-icon: #0c8590;
}

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

html {
  scroll-behavior: smooth;
}

body.rg-page {
  background: var(--page-bg);
  color: var(--page-fg);
  font-family: var(--font);
  font-size: 1rem;
  line-height: 1.5;
  margin: 0;
  min-height: 100vh;
  transition: background 0.25s ease, color 0.25s ease;
}

a {
  color: var(--link);
}

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

/* Theme toggle */
.rg-theme {
  position: fixed;
  left: var(--s2);
  top: var(--s2);
  z-index: 20;
}

.rg-theme__btn {
  align-items: center;
  appearance: none;
  background: var(--toggle-track);
  border: 1px solid var(--toggle-border);
  border-radius: 999px;
  box-shadow:
    inset 0 1px 1px rgba(255, 255, 255, 0.1),
    0 6px 16px rgba(0, 0, 0, 0.35);
  cursor: pointer;
  display: inline-flex;
  height: 2.25rem;
  justify-content: space-between;
  padding: 0.125rem;
  position: relative;
  transition: background 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
  width: 4.25rem;
}

.rg-theme__btn:hover {
  box-shadow:
    inset 0 1px 1px rgba(255, 255, 255, 0.14),
    0 8px 20px rgba(0, 0, 0, 0.4);
}

.rg-theme__btn:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 3px;
}

.rg-theme__icon {
  align-items: center;
  color: var(--toggle-icon);
  display: inline-flex;
  flex: 1;
  height: 100%;
  justify-content: center;
  opacity: 0.45;
  transition: opacity 0.2s ease;
  z-index: 1;
}

.rg-theme__icon svg {
  display: block;
  height: 0.95rem;
  width: 0.95rem;
}

html[data-theme="dark"] .rg-theme__icon--moon,
html[data-theme="light"] .rg-theme__icon--sun {
  opacity: 1;
}

.rg-theme__knob {
  background: var(--toggle-knob);
  border-radius: 50%;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.35);
  height: 1.75rem;
  left: 0.2rem;
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  transition: left 0.22s cubic-bezier(0.2, 0.8, 0.2, 1);
  width: 1.75rem;
  z-index: 2;
}

html[data-theme="light"] .rg-theme__knob {
  left: calc(100% - 1.95rem);
}

/* Layout shell — one content column, shared left edge */
.rg-main {
  margin: 0 auto;
  max-width: calc(var(--width) + var(--s6));
  padding: var(--s5) var(--s3) var(--s6);
}

.rg-intro,
.rg-duo,
.rg-block {
  margin-left: auto;
  margin-right: auto;
  max-width: var(--width);
}

/* Title centered; body content left-aligned (Medium / academic convention) */
.rg-intro {
  margin-bottom: var(--s4);
}

.rg-intro h1 {
  font-family: var(--serif);
  font-size: clamp(1.75rem, 3.4vw, 2.25rem);
  font-weight: 700;
  line-height: 1.25;
  margin: 0 0 var(--s1);
  text-align: center;
}

/* Section rhythm: rule → space → heading close to content */
.rg-section {
  border-top: 1px solid var(--rule);
  margin-top: var(--s4);
  padding-top: var(--s3);
}

.rg-section h2,
.rg-duo h2,
#schedule h2,
#events h2 {
  color: var(--heading);
  font-family: var(--serif);
  font-size: 1.125rem;
  font-weight: 700;
  line-height: 1.25;
  margin: 0 0 var(--s1);
}

#schedule > h2,
#events > h2 {
  text-align: center;
}

.rg-meta {
  border-top: 1px solid var(--rule);
  display: grid;
  gap: var(--s2);
  margin-top: var(--s4);
  padding-top: var(--s3);
}

.rg-meta > div {
  align-items: baseline;
  display: grid;
  gap: var(--s2);
  grid-template-columns: var(--label) minmax(0, 1fr);
}

.rg-meta dt {
  color: var(--heading);
  font-weight: 700;
  margin: 0;
}

.rg-meta dd {
  margin: 0;
  max-width: 38rem;
}

.rg-duo {
  align-items: start;
  border-top: 1px solid var(--rule);
  display: grid;
  gap: var(--s3) var(--s4);
  grid-template-columns: 1fr 1fr;
  margin-top: var(--s4);
  padding-top: var(--s3);
}

.rg-duo .rg-block {
  margin: 0;
  min-width: 0;
  text-align: center;
}

.rg-duo h2 {
  text-align: center;
}

.rg-people {
  display: grid;
  gap: var(--s2);
  justify-items: center;
  list-style: none;
  margin: 0;
  padding: 0;
}

.rg-people li {
  display: grid;
  gap: 0.125rem;
  justify-items: center;
}

.rg-people__name {
  font-weight: 700;
}

.rg-people a {
  font-size: 0.9375rem;
  overflow-wrap: anywhere;
}

.rg-links {
  display: flex;
  flex-direction: column;
  gap: var(--s1);
  margin: 0 auto;
  width: 100%;
  max-width: 12rem;
}

.rg-signup-note {
  font-size: 0.875rem;
  line-height: 1.4;
  margin: var(--s2) auto 0;
  max-width: 18rem;
  opacity: 0.85;
  text-align: center;
}

.rg-links a {
  background: transparent;
  border: 1px solid var(--gold);
  color: var(--page-fg);
  display: block;
  font-weight: 700;
  padding: 0.625rem var(--s2);
  text-align: center;
  text-decoration: none;
  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}

.rg-links a:first-child {
  background: var(--amber);
  border-color: var(--amber);
  color: #fff8ef;
}

.rg-links a:hover {
  background: var(--gold);
  border-color: var(--gold);
  color: var(--brown);
}

.rg-links a:first-child:hover {
  background: #db7a24;
  border-color: #db7a24;
  color: #fff8ef;
}

#schedule,
#events {
  border-top: 1px solid var(--rule);
  margin-top: var(--s4);
  padding-top: var(--s3);
  scroll-margin-top: var(--s2);
}

.rg-status {
  font-size: 0.9375rem;
  font-style: italic;
  margin: 0 0 var(--s2);
  opacity: 0.75;
}

/* Schedule: Imperial/Bath-like plain archive */
.rg-years {
  display: grid;
  gap: var(--s3);
}

.rg-year {
  border: 0;
  margin: 0;
}

.rg-year > summary {
  background: transparent;
  border-bottom: 1px solid var(--hairline);
  cursor: pointer;
  font-size: 1rem;
  font-weight: 700;
  list-style: none;
  padding: var(--s1) 0;
  user-select: none;
}

.rg-year > summary::-webkit-details-marker {
  display: none;
}

.rg-year > summary::after {
  color: var(--gold);
  content: "+";
  float: right;
  font-weight: 700;
}

.rg-year[open] > summary::after {
  content: "–";
}

.rg-year > summary:hover {
  background: var(--row-hover);
}

/* Same colors as the page — no separate table palette */
.rg-table-wrap {
  margin-top: var(--s1);
  overflow-x: auto;
}

.rg-table {
  border-collapse: collapse;
  color: var(--page-fg);
  font-size: 0.9375rem;
  line-height: 1.3;
  table-layout: auto;
  width: 100%;
}

.rg-table th,
.rg-table td {
  border: 0;
  border-bottom: 1px solid var(--hairline);
  padding: 0.5rem 1rem 0.75rem 0;
  text-align: left;
  vertical-align: top;
}

.rg-table thead th {
  border-bottom: 1px solid var(--gold);
  color: var(--heading);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.03em;
  padding-top: 0.35rem;
  padding-bottom: 0.5rem;
  text-transform: uppercase;
}

.rg-table tbody tr:hover td {
  background: var(--row-hover);
}

.rg-table tbody tr:last-child td {
  border-bottom: 0;
}

.rg-table .rg-date {
  font-variant-numeric: tabular-nums;
  font-weight: 600;
  white-space: nowrap;
}

.rg-table .rg-presenter {
  opacity: 0.8;
  white-space: nowrap;
}

.rg-table .rg-title {
  font-weight: 500;
  min-width: 12rem;
}

.rg-table .rg-title a {
  color: inherit;
  font-weight: 500;
  text-decoration: underline;
  text-decoration-color: var(--hairline);
  text-underline-offset: 0.15em;
}

.rg-table .rg-title a:hover {
  color: var(--link-hover);
  text-decoration-color: currentColor;
}

.rg-table .rg-rec {
  text-align: right;
  white-space: nowrap;
}

.rg-table thead .rg-rec {
  text-align: right;
}

.rg-table .rg-rec a {
  font-weight: 700;
  text-decoration: none;
}

.rg-special {
  list-style: none;
  margin: 0;
  padding: 0;
}

.rg-special li {
  border-bottom: 1px solid var(--hairline);
  padding: var(--s1) 0;
}

.rg-special li:first-child {
  border-top: 1px solid var(--hairline);
}

.rg-special strong {
  color: var(--heading);
  display: inline-block;
  font-variant-numeric: tabular-nums;
  min-width: 7rem;
}

@media (max-width: 40em) {
  /* Clear the fixed theme toggle so the title doesn’t sit under it */
  .rg-main {
    padding: calc(var(--s4) + 2.75rem) var(--s2) var(--s5);
  }

  .rg-duo {
    grid-template-columns: 1fr;
    gap: var(--s4);
  }

  .rg-links {
    max-width: none;
  }

  .rg-theme {
    left: var(--s1);
    top: var(--s1);
  }
}

@media (prefers-reduced-motion: reduce) {
  body.rg-page,
  .rg-theme__btn,
  .rg-theme__knob,
  .rg-theme__icon,
  .rg-links a {
    transition: none;
  }
}