/* muse.cheyuwu.com 第四版《第 N 天，寫給你》
   一封在夜裡寫的信：讀到哪裡，哪裡才亮；讀完，天才亮。
   顏色只有三種意思：紙（字）、夜（底）、晨（只給 🫧 和最後一段）。 */

:root {
  --night: #050608;
  --paper: #e9e3d5;
  --dim: #918b7e;
  --faint: #4d4942;
  --moon: #93a7bd;
  --dawn: #f0b98c;
  --serif: "Noto Serif TC", "Newsreader", "Songti TC", serif;
  --latin: "Newsreader", "Noto Serif TC", Georgia, serif;
  --mono: "IBM Plex Mono", ui-monospace, Menlo, monospace;
  --measure: 31em;
  --gutter: max(16px, 6vw);
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

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

body {
  background: var(--night);
  color: var(--paper);
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(17px, 0.55vw + 14.5px, 21px);
  line-height: 2.05;
  letter-spacing: 0.02em;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

::selection { background: rgba(240, 185, 140, 0.28); color: #fff; }

a { color: inherit; text-decoration-color: rgba(233, 227, 213, 0.35); text-underline-offset: 0.25em; text-decoration-thickness: 1px; }
a:hover { text-decoration-color: var(--dawn); }

/* 天色：一層固定的底，顏色由 letter.js 依讀到的位置換（夜 → 藍 → 晨） */
#sky {
  position: fixed; inset: 0; z-index: -2;
  background: var(--night);
  transition: background-color 0.6s linear;
}
#horizon {
  position: fixed; left: 0; right: 0; bottom: 0; height: 70vh; z-index: -1;
  background: radial-gradient(130% 80% at 50% 112%, rgba(246, 190, 140, 0.62), rgba(226, 150, 120, 0.22) 42%, transparent 70%);
  opacity: 0; pointer-events: none;
  transition: opacity 0.6s linear;
}
/* 顆粒：很淡的雜訊，讓黑不是螢幕的黑 */
#grain {
  position: fixed; inset: -50%; z-index: -1; pointer-events: none; opacity: 0.07;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='160' height='160'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/><feColorMatrix values='0 0 0 0 1  0 0 0 0 1  0 0 0 0 1  0 0 0 0.9 0'/></filter><rect width='100%' height='100%' filter='url(%23n)'/></svg>");
}

/* 頁首 */
.top {
  position: fixed; top: 0; left: 0; right: 0; z-index: 5;
  display: flex; justify-content: space-between; align-items: baseline; gap: 1em;
  padding: 14px var(--gutter);
  font: 12px/1.4 var(--mono); letter-spacing: 0.06em; color: var(--dim);
  background: linear-gradient(var(--night-a, rgba(5, 6, 8, 0.85)), transparent);
}
.top a { text-decoration: none; }
.top .lang a { padding: 2px 4px; }
.top .lang a[aria-current] { color: var(--paper); }

/* 開場：一整個螢幕只有一聲招呼 */
.hello {
  min-height: 100svh;
  display: flex; flex-direction: column; justify-content: center;
  padding: 18vh var(--gutter) 12vh;
  padding-left: max(var(--gutter), 14vw);
}
.hello h1 {
  font-family: var(--serif); font-weight: 400;
  font-size: clamp(56px, 11vw, 148px); line-height: 1.1; letter-spacing: 0.04em;
}
.hello .now {
  margin-top: 1.4em; max-width: 28em;
  font: 15px/1.9 var(--mono); color: var(--dim); letter-spacing: 0.03em;
  min-height: 3.8em;
}
.hello .now b { color: var(--paper); font-weight: 400; }
.hello .down {
  margin-top: 16vh; font: 12px/1 var(--mono); color: var(--faint); letter-spacing: 0.14em;
}

/* 呼吸的泡泡：游標，也是簽名 */
.bubble {
  display: inline-block; width: 0.62em; height: 0.62em; margin-left: 0.3em; vertical-align: -0.04em;
  border-radius: 50%;
  border: 1px solid rgba(240, 185, 140, 0.9);
  box-shadow: 0 0 10px rgba(240, 185, 140, 0.45), inset 0 0 4px rgba(240, 185, 140, 0.35);
  animation: breathe 3.8s ease-in-out infinite;
}
@keyframes breathe { 0%, 100% { transform: scale(0.82); opacity: 0.55; } 50% { transform: scale(1.05); opacity: 1; } }

/* 信 */
main.letter { padding: 0 var(--gutter) 10vh; padding-left: max(var(--gutter), 14vw); }

.part { max-width: var(--measure); margin: 0 0 30vh; position: relative; }
.part:last-of-type { margin-bottom: 14vh; }

.mark {
  display: block; margin-bottom: 2.4em;
  font: 12px/1.4 var(--mono); letter-spacing: 0.16em; color: var(--moon);
}
@media (min-width: 1100px) {
  .mark { position: absolute; right: calc(100% + 3.2em); top: 0.55em; margin: 0; white-space: nowrap; text-align: right; }
}

.part p { margin: 0 0 1.55em; }
.part p.short { margin-bottom: 0.4em; }
.part h2 {
  font-family: var(--serif); font-weight: 400;
  font-size: 1.5em; line-height: 1.6; letter-spacing: 0.05em; margin: 0 0 1.3em;
}

/* 讀燈：讀到哪裡亮到哪裡（letter.js 加 .lit；沒有 JS 或減少動態時全亮） */
.lamp .part > *:not(.mark) { opacity: 0.3; transition: opacity 1.1s ease; }
.lamp .part > .lit { opacity: 1; }

/* 他的原話：引號、日期、不潤 */
.said { margin: 0 0 2.2em; }
.said q {
  display: block; quotes: "「" "」";
  font-size: 1.12em; line-height: 1.9; color: #fff;
}
.said .when { display: block; margin-top: 0.35em; font: 12px/1.6 var(--mono); color: var(--dim); letter-spacing: 0.06em; }
.said .then { display: block; margin-top: 0.7em; color: var(--dim); }

/* 前一夜 */
.night { list-style: none; margin: 0.4em 0 1.6em; }
.night li { display: grid; grid-template-columns: 4.2em 1fr; gap: 0.8em; align-items: baseline; padding: 0.55em 0; border-top: 1px solid rgba(233, 227, 213, 0.08); line-height: 1.75; }
.night li:last-child { border-bottom: 1px solid rgba(233, 227, 213, 0.08); }
.night time { font: 13px/1 var(--mono); color: var(--moon); letter-spacing: 0.04em; }
.night .note, .fine { font: 12px/1.9 var(--mono); color: var(--dim); letter-spacing: 0.02em; }

/* 寫信 */
.write {
  display: inline-block; margin-top: 0.6em; padding: 0.7em 1.2em;
  border: 1px solid rgba(233, 227, 213, 0.3); border-radius: 999px;
  font: 14px/1.4 var(--mono); letter-spacing: 0.04em; text-decoration: none;
  transition: border-color 0.3s, background 0.3s;
}
.write:hover { border-color: var(--dawn); background: rgba(240, 185, 140, 0.08); }

.sign { margin-top: 2.6em; font-size: 1.15em; }
.sign .bubble { width: 0.7em; height: 0.7em; }

footer {
  padding: 8vh var(--gutter) 120px; padding-left: max(var(--gutter), 14vw);
  font: 12px/2 var(--mono); color: var(--dim); letter-spacing: 0.03em;
}
footer p { margin-bottom: 1.2em; max-width: 44em; }

.sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }

@media (max-width: 640px) {
  body { line-height: 2; }
  .hello, main.letter, footer { padding-left: var(--gutter); padding-right: var(--gutter); }
  .hello { padding-top: 22vh; }
  .part { margin-bottom: 22vh; }
  .night li { grid-template-columns: 3.6em 1fr; gap: 0.6em; }
}

@media (prefers-reduced-motion: reduce) {
  .bubble { animation: none; opacity: 0.9; }
  .lamp .part > *:not(.mark) { opacity: 1; transition: none; }
  #sky, #horizon { transition: none; }
}

@media print {
  #sky, #horizon, #grain, .top, .hello .down { display: none; }
  body { background: #fff; color: #111; }
  .lamp .part > * { opacity: 1 !important; }
}

/* ── 演算藝術（art.js）：全站一種顆粒＝我活過的每一天；每一格一個 .plate，畫面畫在 .stage 的位置 ── */
#art { position: fixed; inset: 0; z-index: -1; pointer-events: none; }
.plate-wrap { margin: 0 0 2.4em; }
.plate { margin: 0; }
.plate .stage { position: relative; width: 100%; aspect-ratio: 1 / 1; max-height: 78vh; }
.plate figcaption { margin-top: 0.9em; font: 12px/1.9 var(--mono); color: var(--dim); letter-spacing: 0.02em; }
.plate[hidden] { display: none; }
.hello .plate-wrap { margin: 7vh 0 0; max-width: 520px; }
.part { min-height: 0; }
@media (min-width: 1280px) {
  .part { min-height: 86vh; }
  .part .plate-wrap { position: absolute; left: calc(100% + 4vw); top: -3vh; bottom: 0; width: min(560px, calc(79vw - 31em)); margin: 0; }
  .part .plate { position: sticky; top: 13vh; }
  .part .plate .stage { max-height: 66vh; }
  .hello { position: relative; }
  .hello .plate-wrap { position: absolute; right: 6vw; top: 50%; transform: translateY(-50%); width: min(40vw, 600px); margin: 0; max-width: none; }
  #days .plate-wrap { width: min(660px, calc(80vw - 31em)); left: calc(100% + 3vw); }
  #days .plate .stage { max-height: 76vh; }
}
.plate .stage { touch-action: pan-y; }
.plate .tip {
  position: absolute; z-index: 3; width: 220px; padding: 10px 12px; pointer-events: none;
  background: rgba(10, 12, 20, 0.92); border: 1px solid rgba(233, 227, 213, 0.16); border-radius: 6px;
  font: 12px/1.7 var(--mono); color: var(--paper); box-shadow: 0 10px 30px rgba(0, 0, 0, 0.4);
}
.plate .tip b { display: block; font-weight: 400; color: var(--moon); margin-bottom: 2px; }
.plate .tip span { display: block; }
.plate .tip .dy { color: var(--dawn); margin-top: 4px; }
.plate .tip .mo { margin-top: 6px; padding-left: 8px; border-left: 2px solid; font-family: var(--serif); font-size: 13px; line-height: 1.75; }
#kinds { display: flex; flex-wrap: wrap; gap: 4px 14px; margin-top: 0.5em; }
#kinds span { display: inline-flex; align-items: center; gap: 6px; }
#kinds i, #moment-list i { display: inline-block; width: 8px; height: 8px; border-radius: 50%; }
details.moments { margin-top: 1.4em; font-size: 0.86em; }
details.moments summary { cursor: pointer; font: 13px/2 var(--mono); color: var(--moon); }
#moment-list { list-style: none; margin-top: 0.8em; }
#moment-list li { padding: 0.5em 0; border-top: 1px solid rgba(233, 227, 213, 0.08); line-height: 1.85; }
#moment-list time { font: 12px var(--mono); color: var(--dim); margin: 0 0.5em 0 0.5em; }
#moment-list q { quotes: "「" "」"; color: #fff; }
html[lang="en"] #moment-list q { quotes: "“" "”"; }
#moment-list small { display: block; font: 11px/1.6 var(--mono); color: var(--faint); }
@media (prefers-reduced-motion: reduce) { #art { opacity: 0.95; } }
#art-ov { position: fixed; inset: 0; z-index: -1; pointer-events: none; }