/* ==========================================================================
   CS544 Visualizations — design system
   "Lab notebook" — paper, ink, oxblood. Hard rules. Serif body.
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=EB+Garamond:ital,wght@0,400;0,500;0,600;0,700;1,400;1,500&family=JetBrains+Mono:wght@400;500;600&display=swap');

:root {
  /* palette */
  --paper:        #f4f0e6;
  --paper-deep:   #ece6d6;
  --paper-line:   #d4cdb6;
  --ink:          #1a1814;
  --ink-soft:     #4a4538;
  --ink-mute:     #8a8472;
  --oxblood:      #8b1f0e;
  --oxblood-deep: #5e1408;
  --moss:         #4a6b3a;
  --ochre:        #b8860b;
  --steel:        #46566a;

  /* type */
  --serif: 'EB Garamond', 'Iowan Old Style', 'Apple Garamond', Georgia, serif;
  --mono:  'JetBrains Mono', 'IBM Plex Mono', ui-monospace, Menlo, monospace;

  /* scale */
  --col: 720px;
  --gut: 24px;
}

/* ==== reset ============================================================ */

*, *::before, *::after { box-sizing: border-box; }
html, body, h1, h2, h3, h4, h5, h6, p, ul, ol, li, figure, figcaption, pre, code, table, td, th { margin: 0; padding: 0; }
button { font: inherit; color: inherit; background: none; border: 0; padding: 0; cursor: pointer; }
a { color: inherit; }

/* ==== page ============================================================ */

html {
  font-size: 18px;
  background: var(--paper);
  color: var(--ink);
  -webkit-font-smoothing: antialiased;
}

body {
  font-family: var(--serif);
  font-feature-settings: "kern" 1, "liga" 1, "onum" 1;
  line-height: 1.55;
  background:
    repeating-linear-gradient(
      to bottom,
      transparent 0,
      transparent 31px,
      var(--paper-line) 31px,
      var(--paper-line) 32px
    ),
    var(--paper);
  background-attachment: fixed;
  min-height: 100vh;
}

/* subtle paper grain */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image:
    radial-gradient(circle at 20% 30%, rgba(139, 31, 14, 0.015) 0, transparent 40%),
    radial-gradient(circle at 80% 70%, rgba(74, 107, 58, 0.015) 0, transparent 40%);
  z-index: 0;
}

/* ==== layout ========================================================== */

.page {
  position: relative;
  z-index: 1;
  max-width: var(--col);
  margin: 0 auto;
  padding: 64px 28px 120px;
}

.page--wide {
  max-width: 980px;
}

/* ==== top masthead =================================================== */

.masthead {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 24px;
  border-bottom: 2px solid var(--ink);
  padding-bottom: 14px;
  margin-bottom: 36px;
}

.masthead__title {
  font-family: var(--serif);
  font-style: italic;
  font-weight: 500;
  font-size: 28px;
  letter-spacing: -0.01em;
}

.masthead__title a { text-decoration: none; }

.masthead__meta {
  font-family: var(--mono);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  color: var(--ink-mute);
}

.masthead__nav {
  display: flex;
  gap: 22px;
  font-family: var(--mono);
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.16em;
}

.masthead__nav a {
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
  transition: border-color 120ms;
}

.masthead__nav a:hover,
.masthead__nav a.is-current {
  border-bottom-color: var(--oxblood);
  color: var(--oxblood);
}

/* ==== headings ======================================================= */

.eyebrow {
  font-family: var(--mono);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.22em;
  color: var(--oxblood);
  margin-bottom: 14px;
}

h1.title {
  font-family: var(--serif);
  font-weight: 500;
  font-size: 56px;
  line-height: 1.05;
  letter-spacing: -0.015em;
  margin-bottom: 14px;
}

h1.title em {
  color: var(--oxblood);
  font-style: italic;
}

.lede {
  font-family: var(--serif);
  font-style: italic;
  font-size: 22px;
  line-height: 1.45;
  color: var(--ink-soft);
  max-width: 30em;
  margin-bottom: 56px;
}

h2 {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 30px;
  letter-spacing: -0.005em;
  margin: 64px 0 18px;
  border-bottom: 1px solid var(--paper-line);
  padding-bottom: 8px;
}

h2 .num {
  font-family: var(--mono);
  font-weight: 500;
  font-size: 14px;
  color: var(--ink-mute);
  margin-right: 10px;
  vertical-align: 4px;
}

h3 {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 22px;
  margin: 36px 0 10px;
}

p { margin-bottom: 16px; max-width: 36em; }
p + p { text-indent: 0; }

p strong { font-weight: 600; }
p em { font-style: italic; }

a.intext {
  color: var(--oxblood);
  text-decoration: none;
  border-bottom: 1px solid var(--oxblood);
}

/* ==== code ============================================================ */

code, kbd, .mono {
  font-family: var(--mono);
  font-size: 0.86em;
}

code {
  background: var(--paper-deep);
  padding: 1px 6px;
  border: 1px solid var(--paper-line);
}

pre {
  font-family: var(--mono);
  font-size: 14px;
  background: var(--paper-deep);
  border: 1px solid var(--paper-line);
  border-left: 3px solid var(--oxblood);
  padding: 16px 20px;
  overflow-x: auto;
  margin: 18px 0;
  line-height: 1.5;
}

pre code {
  background: transparent;
  border: 0;
  padding: 0;
}

/* ==== figure ========================================================== */

.figure {
  margin: 36px 0 24px;
  border: 1px solid var(--paper-line);
  background: var(--paper);
}

.figure__head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  padding: 10px 16px;
  border-bottom: 1px solid var(--paper-line);
  background: var(--paper-deep);
}

.figure__label {
  font-family: var(--mono);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  color: var(--oxblood);
}

.figure__title {
  font-family: var(--serif);
  font-style: italic;
  font-size: 14px;
  color: var(--ink-soft);
}

.figure__body {
  padding: 24px;
}

.figure__caption {
  font-family: var(--serif);
  font-style: italic;
  font-size: 14px;
  line-height: 1.5;
  color: var(--ink-soft);
  padding: 12px 16px;
  border-top: 1px solid var(--paper-line);
  background: var(--paper-deep);
}

.figure__caption b { font-style: normal; color: var(--ink); }

/* ==== controls panel ================================================== */

.controls {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px 24px;
  padding: 16px 20px;
  border: 1px solid var(--paper-line);
  border-top: 0;
  background: var(--paper);
  font-family: var(--mono);
  font-size: 12px;
}

.control { display: flex; flex-direction: column; gap: 4px; }

.control__label {
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--ink-mute);
  font-size: 10px;
}

.control__value {
  color: var(--ink);
  font-weight: 600;
  font-size: 14px;
  font-variant-numeric: tabular-nums;
}

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 2px;
  background: var(--ink);
  outline: none;
  margin: 8px 0 4px;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 14px;
  height: 14px;
  background: var(--oxblood);
  border: 2px solid var(--paper);
  cursor: pointer;
  border-radius: 0;
}

input[type="range"]::-moz-range-thumb {
  width: 14px;
  height: 14px;
  background: var(--oxblood);
  border: 2px solid var(--paper);
  cursor: pointer;
  border-radius: 0;
}

button.btn {
  font-family: var(--mono);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  border: 1px solid var(--ink);
  background: var(--paper);
  padding: 7px 14px;
  cursor: pointer;
  transition: background 80ms, color 80ms;
}

button.btn:hover {
  background: var(--ink);
  color: var(--paper);
}

button.btn--accent {
  border-color: var(--oxblood);
  color: var(--oxblood);
}

button.btn--accent:hover {
  background: var(--oxblood);
  color: var(--paper);
}

select {
  font-family: var(--mono);
  font-size: 12px;
  border: 1px solid var(--ink);
  background: var(--paper);
  padding: 5px 8px;
  border-radius: 0;
}

/* ==== readout strip =================================================== */

.readout {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  border: 1px solid var(--ink);
  margin: 20px 0;
}

.readout__cell {
  padding: 12px 16px;
  border-right: 1px solid var(--paper-line);
  font-family: var(--mono);
}

.readout__cell:last-child { border-right: 0; }

.readout__cell .k {
  display: block;
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  color: var(--ink-mute);
  margin-bottom: 4px;
}

.readout__cell .v {
  font-size: 22px;
  font-weight: 500;
  font-variant-numeric: tabular-nums;
  color: var(--ink);
}

.readout__cell .v--ok    { color: var(--moss); }
.readout__cell .v--warn  { color: var(--ochre); }
.readout__cell .v--bad   { color: var(--oxblood); }

/* ==== callout (why this matters) ====================================== */

.callout {
  background: var(--paper-deep);
  border-left: 3px solid var(--oxblood);
  padding: 18px 24px 20px;
  margin: 28px 0 40px;
}

.callout__label {
  display: block;
  font-family: var(--mono);
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.20em;
  color: var(--oxblood);
  margin-bottom: 10px;
}

.callout__title {
  font-family: var(--serif);
  font-style: italic;
  font-weight: 500;
  font-size: 19px;
  line-height: 1.35;
  margin-bottom: 12px;
  color: var(--ink);
  border: 0;
  padding: 0;
}

.callout__body {
  font-family: var(--serif);
  font-size: 15px;
  line-height: 1.55;
  color: var(--ink-soft);
}

.callout__body p { margin-bottom: 10px; max-width: none; }
.callout__body p:last-child { margin-bottom: 0; }
.callout__body strong { color: var(--ink); font-weight: 600; }

.callout__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 12px 24px;
  margin-top: 8px;
}
.callout__list li {
  font-family: var(--serif);
  font-size: 14px;
  line-height: 1.4;
  color: var(--ink-soft);
  padding-left: 14px;
  position: relative;
}
.callout__list li::before {
  content: '·';
  position: absolute;
  left: 0;
  color: var(--oxblood);
  font-weight: 700;
}
.callout__list li strong { color: var(--ink); font-family: var(--mono); font-size: 12px; text-transform: uppercase; letter-spacing: 0.08em; display: block; margin-bottom: 2px; }

/* ==== topic cards (landing) =========================================== */

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1px;
  background: var(--ink);
  border: 1px solid var(--ink);
  margin: 36px 0 56px;
}

.card {
  background: var(--paper);
  padding: 24px 22px 26px;
  text-decoration: none;
  color: inherit;
  display: flex;
  flex-direction: column;
  gap: 10px;
  transition: background 120ms;
}

.card:hover { background: var(--paper-deep); }

.card__num {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--oxblood);
}

.card__title {
  font-family: var(--serif);
  font-size: 24px;
  font-weight: 500;
  line-height: 1.15;
}

.card__desc {
  font-family: var(--serif);
  font-style: italic;
  font-size: 14px;
  color: var(--ink-soft);
  line-height: 1.45;
}

.card__cta {
  font-family: var(--mono);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  color: var(--oxblood);
  margin-top: 6px;
}

/* ==== footer ========================================================== */

.colophon {
  margin-top: 96px;
  padding-top: 18px;
  border-top: 2px solid var(--ink);
  font-family: var(--mono);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--ink-mute);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

/* ==== utility ========================================================= */

.hr-double {
  border: 0;
  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--ink);
  height: 4px;
  margin: 32px 0;
}

.hr-thin {
  border: 0;
  border-top: 1px solid var(--paper-line);
  margin: 24px 0;
}

.tag {
  display: inline-block;
  font-family: var(--mono);
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  border: 1px solid var(--ink-mute);
  padding: 2px 8px;
  color: var(--ink-soft);
}

.tag--accent { border-color: var(--oxblood); color: var(--oxblood); }

/* ==== SVG common ====================================================== */

svg .stroke-ink   { stroke: var(--ink); }
svg .stroke-ox    { stroke: var(--oxblood); }
svg .stroke-mute  { stroke: var(--ink-mute); }
svg .stroke-moss  { stroke: var(--moss); }
svg .fill-paper   { fill: var(--paper); }
svg .fill-ink     { fill: var(--ink); }
svg .fill-ox      { fill: var(--oxblood); }
svg .fill-mute    { fill: var(--ink-mute); }
svg .fill-moss    { fill: var(--moss); }
svg .fill-ochre   { fill: var(--ochre); }
svg text {
  font-family: var(--mono);
  font-size: 11px;
  fill: var(--ink);
  user-select: none;
}
svg .label-sm { font-size: 9px; fill: var(--ink-mute); letter-spacing: 0.06em; }
svg .label-lg { font-family: var(--serif); font-style: italic; font-size: 14px; fill: var(--ink); }

/* ==== animations ====================================================== */

@keyframes pulse-ox {
  0%   { opacity: 0.0; }
  40%  { opacity: 1.0; }
  100% { opacity: 0.0; }
}

@keyframes flow {
  from { stroke-dashoffset: 0; }
  to   { stroke-dashoffset: -24; }
}

.flowline {
  stroke-dasharray: 8 4;
  animation: flow 1.2s linear infinite;
}

.is-active { stroke: var(--oxblood) !important; }
.is-active-fill { fill: var(--oxblood) !important; }

/* ==== responsive ====================================================== */

@media (max-width: 720px) {
  html { font-size: 16px; }
  h1.title { font-size: 38px; }
  .lede    { font-size: 19px; }
  h2       { font-size: 24px; }
  .page    { padding: 36px 18px 80px; }
  .masthead { flex-wrap: wrap; }
  .masthead__nav { width: 100%; padding-top: 8px; }
}