/* Layout: one quiet reading column under a thin sky band (the site began as an aerial-photo page); notes are
   listed like a logbook, each dated in its own column. No external fonts or scripts: everything loads from here. */
:root {
  --ink: #1c2733;
  --muted: #5b6a7a;
  --paper: #f6f8fa;
  --rule: #dde4eb;
  --accent: #285d8c;
  --dawn: #e2b98f;
  --code: #edf1f5;
  --sky-top: #d3e2ef;
  --sky-low: #f1ece6;
  --star: rgba(255, 255, 255, 0);
  --serif: "Noto Serif SC", "Source Han Serif SC", "Source Han Serif CN", "Songti SC", "STSong", "SimSun", serif;
  --sans: system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --mono: "JetBrains Mono", "Cascadia Code", Consolas, "SFMono-Regular", Menlo, monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    --ink: #e1e7ed;
    --muted: #93a1b0;
    --paper: #0e131a;
    --rule: #222b36;
    --accent: #8bb7df;
    --dawn: #a9805e;
    --code: #161e28;
    --sky-top: #0a1018;
    --sky-low: #1a2431;
    --star: rgba(226, 236, 248, 0.75);
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.8;
}

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

a:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 2px; }

.wrap {
  max-width: 760px;
  margin: 0 auto;
  padding-left: max(20px, env(safe-area-inset-left, 0px));
  padding-right: max(20px, env(safe-area-inset-right, 0px));
}

/* The sky band ---------------------------------------------------------------------------------------- */
.sky {
  position: relative;
  overflow: hidden;
  background: linear-gradient(180deg, var(--sky-top) 0%, var(--sky-low) 100%);
}

.sky::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    radial-gradient(1.2px 1.2px at 8% 22%, var(--star) 50%, transparent 52%),
    radial-gradient(1px 1px at 19% 64%, var(--star) 50%, transparent 52%),
    radial-gradient(1.4px 1.4px at 33% 14%, var(--star) 50%, transparent 52%),
    radial-gradient(1px 1px at 47% 41%, var(--star) 50%, transparent 52%),
    radial-gradient(1.2px 1.2px at 61% 19%, var(--star) 50%, transparent 52%),
    radial-gradient(1px 1px at 72% 57%, var(--star) 50%, transparent 52%),
    radial-gradient(1.5px 1.5px at 84% 27%, var(--star) 50%, transparent 52%),
    radial-gradient(1px 1px at 93% 48%, var(--star) 50%, transparent 52%);
}

.sky::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent 0%, var(--dawn) 30%, var(--dawn) 70%, transparent 100%);
}

.sky .wrap { position: relative; padding-block: 64px 34px; }

.site-name {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(30px, 6vw, 42px);
  font-weight: 600;
  letter-spacing: 0.06em;
  line-height: 1.3;
}

.site-name a { color: var(--ink); text-decoration: none; }

.intro {
  margin: 14px 0 0;
  max-width: 34em;
  color: var(--muted);
  text-wrap: pretty;
}

/* Home: the logbook of notes ---------------------------------------------------------------------------- */
main.home { padding-block: 40px 8px; }

.section-label {
  display: flex;
  align-items: baseline;
  gap: 10px;
  margin: 0 0 6px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.12em;
  color: var(--muted);
}

.section-label .count { font-family: var(--mono); font-weight: 400; letter-spacing: 0; }

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

.log li {
  display: grid;
  grid-template-columns: 7.2em minmax(0, 1fr);
  column-gap: 28px;
  padding-block: 26px;
  border-top: 1px solid var(--rule);
}

.log time {
  padding-top: 4px;
  font-family: var(--mono);
  font-size: 13px;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.log h2 {
  margin: 0 0 6px;
  font-family: var(--sans);
  font-size: 19px;
  font-weight: 650;
  line-height: 1.5;
  text-wrap: balance;
}

.log h2 a {
  color: var(--ink);
  text-decoration: none;
  background-image: linear-gradient(var(--accent), var(--accent));
  background-repeat: no-repeat;
  background-position: 0 100%;
  background-size: 0 1px;
  transition: background-size 0.25s ease, color 0.2s ease;
}

.log h2 a:hover { color: var(--accent); background-size: 100% 1px; }

.log p { margin: 0; color: var(--muted); }

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 14px;
  margin-top: 10px;
  font-family: var(--mono);
  font-size: 12.5px;
  color: var(--accent);
}

.about { padding-block: 34px 8px; border-top: 1px solid var(--rule); }

.about p { margin: 6px 0 0; max-width: 36em; color: var(--muted); }

/* A note ------------------------------------------------------------------------------------------------- */
.sky .back {
  display: inline-block;
  margin-bottom: 18px;
  font-size: 14px;
  color: var(--muted);
  text-decoration: none;
}

.sky .back:hover { color: var(--accent); }

.note-title {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(25px, 4.6vw, 34px);
  font-weight: 600;
  line-height: 1.4;
  letter-spacing: 0.02em;
  text-wrap: balance;
}

.note-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 16px;
  margin-top: 14px;
  font-family: var(--mono);
  font-size: 13px;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
}

article.note { padding-block: 36px 8px; font-size: 17px; line-height: 1.9; }

article.note > * { max-width: 40em; }

article.note h2 {
  margin: 2.1em 0 0.5em;
  font-family: var(--sans);
  font-size: 20px;
  font-weight: 650;
  line-height: 1.45;
}

article.note p, article.note li { text-wrap: pretty; }

article.note ul { padding-left: 1.3em; }

article.note li { margin: 0.5em 0; }

article.note li::marker { color: var(--dawn); }

code {
  font-family: var(--mono);
  font-size: 0.86em;
  background: var(--code);
  border-radius: 4px;
  padding: 1px 5px;
  overflow-wrap: anywhere;
}

pre {
  max-width: 100%;
  margin: 1.2em 0;
  padding: 16px 18px;
  overflow-x: auto;
  background: var(--code);
  border: 1px solid var(--rule);
  border-radius: 8px;
  line-height: 1.65;
}

pre code { padding: 0; background: none; font-size: 13.5px; overflow-wrap: normal; }

.takeaway {
  margin-top: 2em;
  padding: 14px 18px;
  border-left: 2px solid var(--dawn);
  background: var(--code);
  border-radius: 0 6px 6px 0;
}

/* Footer ----------------------------------------------------------------------------------------------------- */
footer.site { padding-block: 40px 36px; }

footer.site .wrap {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 8px 20px;
  padding-top: 18px;
  border-top: 1px solid var(--rule);
  font-size: 13px;
  color: var(--muted);
}

footer.site a { color: var(--muted); text-decoration: none; }

footer.site a:hover { color: var(--accent); }

@media (max-width: 560px) {
  .sky .wrap { padding-block: 48px 28px; }
  .log li { grid-template-columns: minmax(0, 1fr); row-gap: 4px; padding-block: 22px; }
  .log time { padding-top: 0; }
  article.note { font-size: 16px; }
}

@media (prefers-reduced-motion: reduce) {
  .log h2 a { transition: none; }
}