/* Underflow 心流之下 — theme CSS
   來源:Claude Design「Underflow Brand Book」tokens + 首頁 v6 空
   深海是世界,骨白是聲音,熔岩紅是心臟。一處紅;#FFFFFF 禁用;深海 82 · 骨白 15 · 熔岩 3 */

:root {
  --deep-sea: #0b1418;
  --bone: #e9e4d6;
  --lava: #cb3f47;
  --ink: #1c1512;
  --abyss: #04070a;

  --bone-90: rgba(233, 228, 214, .9);
  --bone-75: rgba(233, 228, 214, .75);
  --bone-60: rgba(233, 228, 214, .6);
  --bone-45: rgba(233, 228, 214, .45);
  --bone-35: rgba(233, 228, 214, .35);
  --bone-line: rgba(233, 228, 214, .14);
  --bone-line-strong: rgba(233, 228, 214, .25);

  --ink-70: rgba(28, 21, 18, .7);
  --ink-55: rgba(28, 21, 18, .55);
  --ink-40: rgba(28, 21, 18, .4);
  --ink-line: rgba(28, 21, 18, .15);

  --font-display: "Cormorant", serif;
  --font-serif: "Noto Serif TC", serif;
  --font-sans: "Noto Sans TC", sans-serif;
  --font-mono: "IBM Plex Mono", monospace;

  --track-label: .3em;
  --track-label-wide: .34em;
  --track-cta: .22em;
  --track-mono: .14em;

  --leading-title: 1.55;
  --leading-body: 2.1;
  --leading-quote: 1.95;

  --edge: 56px;
  --spine: 31%;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bone);
  font-family: var(--font-serif);
  font-weight: 300;
  color: var(--ink);
}

a { color: inherit; text-decoration: none; transition: color .3s ease; }
a:hover { color: var(--lava); }

@keyframes uf-in { from { opacity: 0; } to { opacity: 1; } }
@keyframes uf-line { from { transform: scaleX(0); } to { transform: scaleX(1); } }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .uf-anim, .uf-anim-slow { animation: none !important; opacity: 1 !important; }
}

/* ── 屏(screen)骨架 ── */
.uf-screen { position: relative; height: 100vh; min-height: 620px; }
.uf-screen--tall { min-height: 720px; }

.uf-depth {
  position: absolute; left: var(--edge); bottom: 46px;
  font-family: var(--font-mono); font-size: 12px;
  letter-spacing: var(--track-mono); color: var(--ink-40);
}
.uf-depth--light { color: var(--bone-45); }

.uf-rule { position: absolute; left: 0; right: 0; height: 1px; background: var(--ink-line); }

.uf-anim { animation: uf-in 1.8s .2s ease-out both; }
.uf-anim-slow { animation: uf-in 3s .6s ease-out both; }

/* ── 一 · 水面 ── */
.uf-brand {
  position: absolute; left: var(--edge); top: 44px;
  display: flex; align-items: baseline; gap: 14px;
}
.uf-brand__latin { font-family: var(--font-display); font-weight: 400; font-size: 18px; letter-spacing: .06em; }
.uf-brand__zh { font-family: var(--font-sans); font-weight: 300; font-size: 13px; letter-spacing: .36em; color: var(--ink-40); }

.uf-nav {
  position: absolute; right: var(--edge); top: 46px;
  display: flex; gap: 30px;
  font-family: var(--font-sans); font-weight: 300; font-size: 13px;
  letter-spacing: .26em; color: var(--ink-40);
}

.uf-hero-copy { position: absolute; left: var(--spine); top: 40%; max-width: 430px; }
.uf-hero-copy__term {
  font-family: var(--font-display); font-style: italic; font-weight: 400;
  font-size: 15px; letter-spacing: .08em; color: var(--lava);
}
.uf-hero-copy__def {
  margin-top: 34px; font-weight: 300; font-size: 22px;
  line-height: 2.5; letter-spacing: .06em; text-wrap: pretty;
}
.uf-hero-copy__src {
  margin-top: 30px; font-family: var(--font-sans); font-weight: 300;
  font-size: 13px; letter-spacing: .18em; color: var(--ink-40);
}

.uf-hero-plate {
  position: absolute; right: var(--edge); bottom: 46px;
  width: min(260px, 20vw);
}
.uf-hero-plate img {
  width: 100%; aspect-ratio: 3.6 / 1; object-fit: cover;
  object-position: center 60%; display: block;
}

.uf-dive-cue {
  position: absolute; left: 50%; bottom: 44px; transform: translateX(-50%);
  display: flex; flex-direction: column; align-items: center; gap: 12px;
}
.uf-dive-cue__line { width: 1px; height: 34px; background: var(--ink-line); }
.uf-dive-cue__label {
  font-family: var(--font-sans); font-weight: 300; font-size: 13px;
  letter-spacing: .36em; color: var(--ink-40);
}

/* ── 二 · 可以訓練 ── */
.uf-train-copy { position: absolute; left: var(--spine); top: calc(30% + 82px); max-width: 430px; }
.uf-train-copy__lead { font-weight: 300; font-size: 22px; line-height: 2.5; letter-spacing: .06em; text-wrap: pretty; }
.uf-train-copy__body {
  margin-top: 36px; font-family: var(--font-sans); font-weight: 300;
  font-size: 13px; line-height: 2.4; letter-spacing: .04em; color: var(--ink-55);
}

/* ── 三 / 五 · 滿版影像 ── */
.uf-full-img { width: 100%; height: 100%; object-fit: cover; display: block; }
.uf-full-img--interface { object-position: center 32%; }
.uf-full-img--float { object-position: center 28%; }

/* ── 四 · 文章 ── */
.uf-articles { position: absolute; left: var(--spine); top: calc(19% + 86px); right: var(--edge); display: flex; flex-direction: column; gap: 64px; }
.uf-article-row {
  display: grid; grid-template-columns: 24px minmax(0, 1fr) 170px;
  align-items: baseline; gap: 30px;
}
.uf-article-row__no { font-family: var(--font-mono); font-size: 12px; color: var(--ink-40); }
.uf-article-row__title { font-weight: 300; font-size: 22px; line-height: 1.9; letter-spacing: .05em; }
.uf-article-row__meta {
  font-family: var(--font-sans); font-weight: 300; font-size: 13px;
  letter-spacing: .2em; color: var(--ink-40); text-align: right;
}
.uf-articles-empty { font-family: var(--font-sans); font-weight: 300; font-size: 13px; letter-spacing: .2em; color: var(--ink-40); }

/* ── 五 · 訪談 ── */
.uf-quote { position: absolute; left: var(--spine); bottom: 10%; max-width: 430px; }
.uf-quote__text { font-weight: 300; font-size: 20px; line-height: 2.5; letter-spacing: .06em; color: var(--bone); text-wrap: pretty; }
.uf-quote__row { margin-top: 30px; display: flex; align-items: baseline; gap: 26px; flex-wrap: wrap; }
.uf-quote__attr { font-family: var(--font-display); font-style: italic; font-weight: 400; font-size: 15px; letter-spacing: .06em; color: var(--bone-60); }
.uf-quote__cta { font-family: var(--font-sans); font-weight: 300; font-size: 13px; letter-spacing: .26em; color: var(--bone); }

/* ── 六 · 信 ── */
.uf-letter { background: var(--abyss); color: var(--bone); }
.uf-letter .uf-rule { background: var(--bone-line); }
.uf-rule__dot {
  position: absolute; left: var(--spine); top: -3px;
  width: 7px; height: 7px; border-radius: 50%; background: var(--lava);
}
.uf-letter-copy { position: absolute; left: var(--spine); top: calc(9% + 92px); max-width: 430px; }
.uf-letter-copy__lead { font-weight: 300; font-size: 21px; line-height: 2.4; letter-spacing: .06em; }

.uf-subscribe { margin-top: 64px; display: flex; align-items: stretch; max-width: 400px; }
.uf-subscribe input {
  flex: 1; border: none; border-bottom: 1px solid var(--bone-line-strong);
  padding: 12px 2px; font-size: 14px; color: var(--bone);
  background: transparent; outline: none;
  font-family: var(--font-sans); font-weight: 300; border-radius: 0;
}
.uf-subscribe input::placeholder { color: var(--bone-45); }
.uf-subscribe button {
  border: none; background: transparent;
  border-bottom: 1px solid var(--lava); color: var(--lava);
  padding: 12px 2px 12px 28px;
  font-family: var(--font-sans); font-size: 13px; letter-spacing: .26em;
  cursor: pointer; display: flex; align-items: center; transition: color .3s ease;
}
.uf-subscribe button:hover { color: var(--bone); }

.uf-form-note { margin-top: 22px; font-family: var(--font-sans); font-weight: 300; font-size: 13px; letter-spacing: .1em; color: var(--bone-60); display: none; }
form[data-members-form].success ~ .uf-form-note--success { display: block; }
form[data-members-form].error ~ .uf-form-note--error { display: block; color: var(--lava); }

.uf-footer {
  position: absolute; left: var(--edge); right: var(--edge); bottom: 44px;
  display: flex; justify-content: space-between; align-items: baseline; gap: 20px; flex-wrap: wrap;
}
.uf-footer__brand { display: flex; align-items: baseline; gap: 14px; }
.uf-footer__latin { font-family: var(--font-display); font-weight: 400; font-size: 16px; letter-spacing: .14em; color: var(--bone-45); }
.uf-footer__zh { font-family: var(--font-sans); font-weight: 300; font-size: 13px; letter-spacing: .3em; color: var(--bone-35); }
.uf-footer__links { display: flex; gap: 28px; font-family: var(--font-sans); font-weight: 300; font-size: 13px; letter-spacing: .24em; color: var(--bone-45); }
.uf-footer__depth { font-family: var(--font-mono); font-size: 12px; letter-spacing: var(--track-mono); color: var(--bone-35); }

/* ── 文章內頁(post.hbs,v1 簡版;完整文章頁設計之後接)── */
.uf-post { max-width: 640px; margin: 0 auto; padding: 160px 24px 140px; }
.uf-post__kicker { font-family: var(--font-sans); font-weight: 300; font-size: 13px; letter-spacing: .26em; color: var(--ink-40); }
.uf-post__title { margin-top: 30px; font-weight: 600; font-size: 30px; line-height: var(--leading-title); letter-spacing: .04em; }
.uf-post__meta { margin-top: 26px; font-family: var(--font-mono); font-size: 12px; letter-spacing: var(--track-mono); color: var(--ink-40); }
.uf-post__content { margin-top: 72px; font-size: 17px; line-height: var(--leading-body); letter-spacing: .04em; }
.uf-post__content h2 { margin: 72px 0 24px; font-weight: 600; font-size: 21px; line-height: var(--leading-title); letter-spacing: .05em; }
.uf-post__content h3 { margin: 56px 0 20px; font-weight: 600; font-size: 18px; }
.uf-post__content p { margin: 0 0 34px; }
.uf-post__content a { border-bottom: 1px solid var(--ink-line); }
.uf-post__content a:hover { border-color: var(--lava); }
.uf-post__content blockquote { margin: 48px 0; padding-left: 26px; border-left: 1px solid var(--lava); font-size: 18px; line-height: var(--leading-quote); color: var(--ink-70); }
.uf-post__content img { max-width: 100%; height: auto; }
.uf-post__content ul, .uf-post__content ol { margin: 0 0 34px; padding-left: 1.4em; }
.uf-post__content li { margin-bottom: 12px; }
.uf-post__back { position: absolute; left: var(--edge); top: 44px; }

/* ── 響應式 ── */
@media (max-width: 820px) {
  :root { --edge: 24px; --spine: 24px; }
  .uf-hero-copy, .uf-train-copy, .uf-articles, .uf-quote, .uf-letter-copy { max-width: none; right: 24px; }
  .uf-hero-copy__def, .uf-train-copy__lead, .uf-article-row__title { font-size: 19px; }
  .uf-article-row { grid-template-columns: 24px minmax(0, 1fr); }
  .uf-article-row__meta { grid-column: 2; text-align: left; margin-top: 6px; }
  .uf-nav { gap: 18px; letter-spacing: .18em; }
  .uf-hero-plate { display: none; }
  .uf-footer { flex-direction: column; gap: 18px; }
}