@font-face {
  font-family: "Departure Mono";
  src: url("assets/fonts/DepartureMono-Regular.woff2") format("woff2");
  font-style: normal;
  font-weight: 400;
  font-display: swap;
}

:root {
  color-scheme: dark;
  --background: #151922;
  --text: #d4d9d4;
  --green: #7dff8c;
  --blue: #6eb5ff;
  --selection: #23482a;
  --muted: #a0a9b8;
  --dim: #7f899a;
  --red: #ff6b7d;
  --border: #394251;
  --border-strong: #536175;
  --lights-off: inline;
  --lights-on: none;
}

@media (prefers-color-scheme: light) {
  :root:not([data-theme="dark"]) {
    color-scheme: light;
    --background: #f3f1ea;
    --text: #262b35;
    --green: #15722a;
    --blue: #1d5bbf;
    --selection: #c4e6c8;
    --muted: #586172;
    --dim: #5f6878;
    --red: #c42a40;
    --border: #c8c9c6;
    --border-strong: #98a0ab;
    --lights-off: none;
    --lights-on: inline;
  }
}

:root[data-theme="light"] {
  color-scheme: light;
  --background: #f3f1ea;
  --text: #262b35;
  --green: #15722a;
  --blue: #1d5bbf;
  --selection: #c4e6c8;
  --muted: #586172;
  --dim: #5f6878;
  --red: #c42a40;
  --border: #c8c9c6;
  --border-strong: #98a0ab;
  --lights-off: none;
  --lights-on: inline;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  color: var(--text);
  background: var(--background);
  font-family: "Departure Mono", monospace;
  font-size: 16.5px;
  line-height: 1.55;
  -webkit-font-smoothing: none;
}

::selection { background: var(--selection); }

main {
  width: min(100% - 40px, 760px);
  margin: 0 auto;
  padding: 28px 0 52px;
}

section { margin-bottom: 30px; }
.intro { display: flow-root; }

h1,
h2 {
  margin: 0 0 8px;
  color: var(--green);
  font: inherit;
}

p { margin: 0 0 8px; }

a {
  color: var(--blue);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

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

.theme-toggle {
  position: absolute;
  top: 28px;
  right: 28px;
  padding: 5px 8px;
  border: 1px solid var(--border-strong);
  color: var(--dim);
  background: var(--background);
  font: inherit;
  font-size: 11px;
  line-height: 1.2;
  text-transform: uppercase;
  cursor: pointer;
}

.theme-toggle:hover {
  border-color: var(--green);
  color: var(--green);
}

.theme-toggle:focus-visible {
  outline: 1px solid var(--green);
  outline-offset: 2px;
}

.lights-off { display: var(--lights-off); }
.lights-on { display: var(--lights-on); }

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

.work-list li {
  position: relative;
  margin-bottom: 6px;
  padding-left: 20px;
}

.work-list li::before {
  position: absolute;
  top: 0.7em;
  left: 3px;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: currentColor;
  content: "";
  transform: translateY(-50%);
}

.writing-nav { margin-bottom: 30px; }
.writing-header { margin-bottom: 30px; }
.writing-date { color: var(--muted); }
.writing-body p { margin-bottom: 20px; }
.writing-body { overflow-wrap: break-word; }

.writing-diagram {
  margin: 24px 0 30px;
  padding: 20px;
  border: 1px solid var(--border);
  font-size: 13.75px;
  text-align: center;
}

.flow-steps {
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: flow-step;
}

.flow-steps li,
.flow-node {
  padding: 10px 12px;
  border: 1px solid var(--border-strong);
}

.flow-steps li {
  position: relative;
  counter-increment: flow-step;
}

.flow-steps li::before { content: counter(flow-step) ". "; }
.flow-steps li + li { margin-top: 32px; }

.flow-steps li + li::after {
  position: absolute;
  top: -29px;
  left: 0;
  width: 100%;
  color: var(--green);
  content: "↓";
}

.flow-inputs,
.flow-branches {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.writing-diagram .flow-label {
  margin: 8px 0;
  color: var(--green);
}

.flow-note { color: var(--muted); }
.writing-diagram p.flow-note { margin: 8px 0 0; }

.page-end {
  display: flex;
  width: 41ch;
  max-width: 100%;
  margin: 96px auto 0;
  color: var(--green);
  font-size: 13.75px;
  line-height: 1.05;
  white-space: nowrap;
  user-select: none;
}

.page-end::before,
.page-end::after { content: "+"; }

.page-end.is-turned::before,
.page-end.is-turned::after { content: "×"; }

.page-end span {
  flex: 1;
  min-width: 0;
  overflow: hidden;
}

.page-end span::before { content: "----------------------------------------------------------------------------------------------------------------------------------------------------------------"; }

.snake-panel {
  width: max-content;
  margin: 80px auto 0;
  padding: 14px;
  color: var(--green);
  background: var(--background);
  font-size: 13.75px;
  line-height: 1.18;
  user-select: none;
}

.snake-header {
  display: flex;
  justify-content: space-between;
  margin-bottom: 6px;
  color: var(--text);
}

#snake-status,
.snake-note {
  color: var(--dim);
  font-size: 11px;
}

#snake-board {
  margin: 0;
  color: var(--green);
  font: inherit;
  line-height: 1.05;
}

.snake-note { margin: 6px 0 0; }

.snake-panel.is-crashed {
  color: var(--red);
}

.snake-panel.is-crashed #snake-board,
.snake-panel.is-crashed #snake-status {
  animation: snake-redout 260ms steps(3) forwards;
}

@keyframes snake-redout {
  from { color: var(--green); }
  to { color: var(--red); }
}

@media (max-width: 600px) {
  body { font-size: 13.75px; }
  main {
    width: 100%;
    padding: 18px 14px 36px;
  }
  section { margin-bottom: 26px; }
  .theme-toggle { top: 16px; right: 14px; }
  .writing-diagram { padding: 12px; font-size: 11px; }
  .flow-inputs, .flow-branches { gap: 10px; }
  .flow-steps li, .flow-node { padding: 8px; }
  .page-end,
  .snake-panel { font-size: 11px; }
  #snake-status, .snake-note { font-size: 11px; }
}

@media (prefers-reduced-motion: reduce) {
  .snake-panel.is-crashed #snake-board,
  .snake-panel.is-crashed #snake-status { animation: none; color: var(--red); }
}