/* 深淵號：深海聲納。底色是越往下越暗的海水，唯一的強調色是海沫綠，用在「可以按」和「目前深度」 */
:root {
  --sea-0: #08131b;
  --sea-1: #0c1a24;
  --sea-2: #11222e;
  --sea-3: #172c3a;
  --line: #1f3546;
  --line-2: #2c4659;
  --ink: #e1e9ee;
  --ink-2: #a3b6c2;
  --ink-3: #7590a1;
  --foam: #7fd8c8;
  --foam-ink: #062019;
  --foam-dim: rgb(127 216 200 / 0.14);
  --coral: #f08d74;
  --ok: #8fd19e;
  --r-lg: 14px;
  --r: 9px;
  --r-sm: 6px;
  --f-text: "Noto Sans TC", system-ui, sans-serif;
  --f-head: "Noto Serif TC", "Noto Sans TC", serif;
  --f-mono: "JetBrains Mono", ui-monospace, monospace;
  --wrap: 1080px;
  color-scheme: dark;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  background: var(--sea-0);
  background-image: linear-gradient(180deg, #0f2230 0, var(--sea-0) 520px);
  color: var(--ink);
  font: 400 15.5px/1.75 var(--f-text);
  line-break: strict;
  word-break: keep-all;
  overflow-wrap: anywhere;
}
a { color: inherit; }
img { max-width: 100%; display: block; }
button, input, textarea, select { font: inherit; color: inherit; }
:focus-visible { outline: 2px solid var(--foam); outline-offset: 2px; border-radius: 4px; }
.skip { position: absolute; left: -999px; top: 8px; background: var(--foam); color: var(--foam-ink); padding: 6px 12px; border-radius: var(--r-sm); z-index: 10; }
.skip:focus { left: 8px; }
h1, h2, h3, .kw, .btn, .nav a, .tag { word-break: keep-all; overflow-wrap: anywhere; }
h1, h2 { font-family: var(--f-head); font-weight: 700; letter-spacing: 0.01em; text-wrap: balance; }
.num { font-family: var(--f-mono); font-variant-numeric: tabular-nums; }

/* ── 頁首 ── */
.bar {
  position: sticky; top: 0; z-index: 5;
  display: flex; align-items: center; gap: 28px;
  padding: 12px max(16px, calc((100vw - var(--wrap)) / 2));
  background: rgb(8 19 27 / 0.86);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.brand { display: flex; align-items: center; gap: 9px; text-decoration: none; font: 700 18px var(--f-head); letter-spacing: 0.08em; }
.brand-mark { width: 24px; height: 24px; color: var(--foam); }
.nav { display: flex; gap: 4px; }
.nav a { text-decoration: none; color: var(--ink-2); padding: 6px 12px; border-radius: var(--r-sm); font-size: 14.5px; transition: color .15s, background .15s; }
.nav a:hover { color: var(--ink); background: var(--sea-2); }
.nav a[aria-current="page"] { color: var(--ink); background: var(--sea-3); }
.who { margin-left: auto; display: flex; align-items: center; gap: 10px; font-size: 14px; }
.who img { width: 28px; height: 28px; border-radius: 50%; }
.who .tier { font: 500 12px var(--f-mono); color: var(--foam); border: 1px solid var(--line-2); border-radius: 999px; padding: 1px 8px; }

main { flex: 1; width: 100%; max-width: var(--wrap); margin: 0 auto; padding: 40px 16px 72px; }
main:focus { outline: none; }
.foot { display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; padding: 20px max(16px, calc((100vw - var(--wrap)) / 2)); border-top: 1px solid var(--line); color: var(--ink-3); font-size: 13px; }

/* ── 按鈕 ── */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  min-height: 42px; padding: 0 18px;
  border-radius: var(--r); border: 1px solid var(--line-2);
  background: var(--sea-2); color: var(--ink);
  font-weight: 500; font-size: 15px; text-decoration: none; cursor: pointer;
  transition: background .15s, border-color .15s, transform .1s;
}
.btn:hover { background: var(--sea-3); border-color: var(--ink-3); }
.btn:active { transform: translateY(1px); }
.btn.primary { background: var(--foam); border-color: var(--foam); color: var(--foam-ink); }
.btn.primary:hover { background: #95e2d4; }
.btn.small { min-height: 34px; padding: 0 12px; font-size: 14px; }
.btn.ghost { background: transparent; }
.btn[disabled] { opacity: .5; cursor: not-allowed; }
.btn svg { width: 18px; height: 18px; }
.link { background: none; border: 0; padding: 0; color: var(--ink-2); text-decoration: underline; text-underline-offset: 3px; cursor: pointer; font-size: 14px; }
.link:hover { color: var(--ink); }

/* ── 首頁 ── */
.hero { display: grid; grid-template-columns: 1.25fr 0.75fr; gap: 48px; align-items: center; padding: 24px 0 56px; }
.hero h1 { font-size: clamp(34px, 5vw, 56px); line-height: 1.2; margin: 0 0 18px; }
.hero p.lead { color: var(--ink-2); font-size: 17px; max-width: 32em; margin: 0 0 28px; }
.hero .cta { display: flex; gap: 12px; flex-wrap: wrap; align-items: center; }
.hero .cta small { color: var(--ink-3); font-size: 13px; }
.sonar { position: relative; aspect-ratio: 1; max-width: 340px; width: 100%; justify-self: center; }
.sonar svg { width: 100%; height: 100%; }
.sonar .sweep { transform-origin: 50% 50%; animation: sweep 6s linear infinite; }
@keyframes sweep { to { transform: rotate(360deg); } }
@media (prefers-reduced-motion: reduce) { .sonar .sweep { animation: none; } }

.notice { display: flex; gap: 14px; align-items: center; justify-content: space-between; flex-wrap: wrap; padding: 14px 18px; border: 1px solid rgb(127 216 200 / .28); border-radius: var(--r); background: var(--foam-dim); margin-bottom: 28px; }
.notice.warn { border-color: rgb(240 141 116 / .32); background: rgb(240 141 116 / .08); }

.decks { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1px; background: var(--line); border: 1px solid var(--line); border-radius: var(--r-lg); overflow: hidden; }
.deck { background: var(--sea-1); padding: 26px 24px 28px; display: flex; flex-direction: column; gap: 10px; text-decoration: none; transition: background .15s; }
.deck:hover { background: var(--sea-2); }
.deck .lvl { font: 500 12px var(--f-mono); color: var(--ink-3); letter-spacing: 0.06em; }
.deck h3 { margin: 0; font-size: 19px; }
.deck p { margin: 0; color: var(--ink-2); font-size: 14.5px; }
.deck .go { margin-top: auto; padding-top: 8px; color: var(--foam); font-size: 14px; }

.section-h { display: flex; align-items: baseline; justify-content: space-between; gap: 16px; margin: 56px 0 18px; }
.section-h h2 { margin: 0; font-size: 22px; }
.section-h a { color: var(--ink-2); font-size: 14px; }

/* ── 入門課：深度表 ── */
.page-h { margin-bottom: 32px; }
.page-h h1 { font-size: clamp(28px, 4vw, 38px); margin: 0 0 8px; line-height: 1.3; }
.page-h p { margin: 0; color: var(--ink-2); max-width: 40em; }
.depth-now { display: inline-flex; gap: 10px; align-items: baseline; margin-top: 16px; padding: 6px 14px; border: 1px solid var(--line-2); border-radius: 999px; font-size: 14px; color: var(--ink-2); }
.depth-now b { font: 500 15px var(--f-mono); color: var(--foam); }

.dive { list-style: none; margin: 0; padding: 0; position: relative; }
.dive::before { content: ""; position: absolute; left: 92px; top: 12px; bottom: 12px; width: 2px; background: linear-gradient(var(--line-2), var(--line) 70%, transparent); }
.dive li { position: relative; display: grid; grid-template-columns: 80px 26px 1fr; gap: 0 16px; align-items: start; }
.dive .m { font: 500 13px var(--f-mono); color: var(--ink-3); text-align: right; padding-top: 22px; }
.dive .dot { width: 14px; height: 14px; margin: 24px 0 0 6px; border-radius: 50%; border: 2px solid var(--line-2); background: var(--sea-0); position: relative; z-index: 1; }
.dive li.done .dot { background: var(--foam); border-color: var(--foam); }
.dive li.done .m { color: var(--foam); }
.unit-card { display: block; text-decoration: none; padding: 16px 20px; margin: 6px 0; border-radius: var(--r); border: 1px solid transparent; transition: background .15s, border-color .15s; }
.unit-card:hover { background: var(--sea-1); border-color: var(--line); }
.unit-card .t { display: flex; gap: 12px; align-items: baseline; flex-wrap: wrap; }
.unit-card h3 { margin: 0; font-size: 18px; }
.unit-card .meta { font: 400 12.5px var(--f-mono); color: var(--ink-3); }
.unit-card p { margin: 4px 0 0; color: var(--ink-2); font-size: 14.5px; }
.unit-card.locked h3 { color: var(--ink-2); }
.tag { font: 500 11.5px var(--f-mono); padding: 1px 7px; border-radius: 999px; border: 1px solid var(--line-2); color: var(--ink-3); }
.tag.foam { color: var(--foam); border-color: rgb(127 216 200 / .35); }
.tag.coral { color: var(--coral); border-color: rgb(240 141 116 / .35); }

/* ── 單元內容 ── */
.reader { display: grid; grid-template-columns: minmax(0, 1fr) 240px; gap: 56px; }
.crumb { font: 500 13px var(--f-mono); color: var(--ink-3); margin-bottom: 10px; }
.crumb a { color: var(--ink-3); text-decoration: none; }
.crumb a:hover { color: var(--ink); }
.prose { max-width: 38em; }
.prose h2 { font-size: 20px; margin: 36px 0 10px; }
.prose p { margin: 0 0 16px; }
.prose ul, .prose ol { margin: 0 0 18px; padding-left: 1.3em; }
.prose li { margin: 4px 0; }
.prose li::marker { color: var(--foam); }
.video { aspect-ratio: 16 / 9; border-radius: var(--r-lg); overflow: hidden; background: var(--sea-1); border: 1px solid var(--line); margin-bottom: 28px; }
.video iframe, .video video { width: 100%; height: 100%; border: 0; display: block; }
.video.empty { display: grid; place-items: center; color: var(--ink-3); font-size: 14px; }
.side { position: sticky; top: 88px; align-self: start; display: flex; flex-direction: column; gap: 14px; font-size: 14px; }
.side .box { border: 1px solid var(--line); border-radius: var(--r); padding: 14px 16px; background: var(--sea-1); }
.side .box h4 { margin: 0 0 6px; font-size: 13px; color: var(--ink-3); font-weight: 500; }
.pager { display: flex; justify-content: space-between; gap: 12px; margin-top: 40px; padding-top: 24px; border-top: 1px solid var(--line); flex-wrap: wrap; }

/* 練習題 */
.quiz { margin-top: 48px; }
.quiz > h2 { font-size: 22px; margin: 0 0 4px; }
.quiz > p { color: var(--ink-2); margin: 0 0 20px; font-size: 14.5px; }
.q { border: 1px solid var(--line); border-radius: var(--r-lg); padding: 20px 22px; margin-bottom: 14px; background: var(--sea-1); }
.q .qn { font: 500 12px var(--f-mono); color: var(--ink-3); }
.q h3 { font-size: 16.5px; margin: 4px 0 14px; font-family: var(--f-text); font-weight: 500; line-height: 1.6; }
.opts { display: grid; gap: 8px; }
.opt { text-align: left; display: flex; gap: 12px; align-items: flex-start; padding: 10px 14px; border-radius: var(--r); border: 1px solid var(--line-2); background: var(--sea-0); cursor: pointer; line-height: 1.6; transition: border-color .15s, background .15s; }
.opt:hover:not([disabled]) { border-color: var(--ink-3); background: var(--sea-2); }
.opt .k { font: 500 13px var(--f-mono); color: var(--ink-3); padding-top: 1px; }
.opt.right { border-color: var(--ok); background: rgb(143 209 158 / .08); }
.opt.wrong { border-color: var(--coral); background: rgb(240 141 116 / .07); }
.opt[disabled] { cursor: default; }
.explain { margin-top: 12px; padding: 12px 14px; border-radius: var(--r); background: var(--sea-2); font-size: 14.5px; color: var(--ink-2); }
.explain b { color: var(--ink); }

/* ── 表單、列表 ── */
.cols { display: grid; grid-template-columns: minmax(0, 1fr) 360px; gap: 40px; align-items: start; }
.panel { border: 1px solid var(--line); border-radius: var(--r-lg); background: var(--sea-1); padding: 22px; }
.panel h2 { font-size: 19px; margin: 0 0 4px; }
.panel > p.sub { margin: 0 0 18px; color: var(--ink-2); font-size: 14px; }
.field { display: grid; gap: 6px; margin-bottom: 16px; }
.field label, .field .lbl { font-size: 13.5px; color: var(--ink-2); }
.field input[type=text], .field textarea { width: 100%; padding: 10px 12px; border-radius: var(--r); border: 1px solid var(--line-2); background: var(--sea-0); }
.field textarea { min-height: 150px; resize: vertical; line-height: 1.7; }
.field input:focus, .field textarea:focus { outline: none; border-color: var(--foam); }
.hint { font-size: 12.5px; color: var(--ink-3); }
.seg { display: inline-flex; border: 1px solid var(--line-2); border-radius: var(--r); overflow: hidden; }
.seg button { border: 0; background: transparent; padding: 7px 14px; cursor: pointer; color: var(--ink-2); font-size: 14px; }
.seg button + button { border-left: 1px solid var(--line-2); }
.seg button[aria-pressed="true"] { background: var(--sea-3); color: var(--ink); }
.file { position: relative; display: inline-flex; width: fit-content; }
.file input { position: absolute; inset: 0; opacity: 0; cursor: pointer; }
.file:focus-within { outline: 2px solid var(--foam); outline-offset: 2px; border-radius: var(--r); }
.thumbs { display: flex; gap: 8px; flex-wrap: wrap; }
.thumbs img { width: 72px; height: 54px; object-fit: cover; border-radius: var(--r-sm); border: 1px solid var(--line-2); }
.err { color: var(--coral); font-size: 14px; margin: 0 0 12px; }

.list { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--line); }
.list li { border-bottom: 1px solid var(--line); }
.list a { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 4px 12px; padding: 14px 4px; text-decoration: none; }
.list .s { white-space: nowrap; }
.list a:hover { background: var(--sea-1); }
.list .t { font-weight: 500; }
.list .d { font: 400 12.5px var(--f-mono); color: var(--ink-3); grid-column: 1; }
.list .s { grid-row: 1 / span 2; grid-column: 2; align-self: center; }
.empty-note { color: var(--ink-3); padding: 28px 4px; font-size: 14.5px; }

.thread { max-width: 760px; }
.msg { border: 1px solid var(--line); border-radius: var(--r-lg); padding: 18px 20px; margin-bottom: 14px; background: var(--sea-1); }
.msg.staff { border-color: rgb(127 216 200 / .3); }
.msg .h { display: flex; gap: 10px; align-items: baseline; flex-wrap: wrap; font-size: 13px; color: var(--ink-3); margin-bottom: 8px; }
.msg .h b { color: var(--ink); font-weight: 500; font-size: 14px; }
.msg .b { white-space: pre-wrap; overflow-wrap: anywhere; }
.shots { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 10px; margin-top: 14px; }
.shots a img { border-radius: var(--r); border: 1px solid var(--line-2); }
.admin-tools { display: flex; gap: 10px; flex-wrap: wrap; align-items: center; margin: 4px 0 18px; }

/* ── 方案 ── */
.plans { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; align-items: stretch; }
.plan { border: 1px solid var(--line); border-radius: var(--r-lg); background: var(--sea-1); padding: 26px 24px; display: flex; flex-direction: column; }
.plan.main { border-color: rgb(127 216 200 / .45); background: linear-gradient(180deg, var(--foam-dim), var(--sea-1) 45%); }
.plan .depth { font: 500 12px var(--f-mono); color: var(--ink-3); letter-spacing: .06em; }
.plan h3 { margin: 6px 0 2px; font: 700 22px var(--f-head); }
.plan .price { margin: 10px 0 2px; font: 500 26px var(--f-mono); }
.plan .price small { font-size: 13px; color: var(--ink-3); }
.plan .note { color: var(--ink-3); font-size: 13px; min-height: 1.6em; }
.plan ul { list-style: none; padding: 0; margin: 18px 0 22px; display: grid; gap: 8px; font-size: 14.5px; }
.plan li { padding-left: 20px; position: relative; }
.plan li::before { content: ""; position: absolute; left: 2px; top: .7em; width: 8px; height: 2px; background: var(--foam); }
.plan .btn { margin-top: auto; }
.routes { margin-top: 48px; }
.routes table { width: 100%; border-collapse: collapse; font-size: 14.5px; }
.routes th, .routes td { text-align: left; padding: 12px 10px; border-bottom: 1px solid var(--line); vertical-align: top; }
.routes th { color: var(--ink-3); font-weight: 500; font-size: 13px; }
.fineprint { color: var(--ink-3); font-size: 13px; margin-top: 18px; }

.toast { position: fixed; left: 50%; bottom: 24px; transform: translateX(-50%); background: var(--sea-3); border: 1px solid var(--line-2); padding: 10px 18px; border-radius: var(--r); font-size: 14px; z-index: 20; box-shadow: 0 8px 30px rgb(0 0 0 / .4); }
.skeleton { color: var(--ink-3); padding: 40px 0; }

/* ── 手機 ── */
@media (max-width: 1080px) and (min-width: 861px) { .plans { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 860px) {
  .bar { gap: 12px; flex-wrap: wrap; padding-top: 10px; padding-bottom: 0; }
  .nav { order: 3; width: 100%; overflow-x: auto; margin: 0 -6px; padding-bottom: 6px; }
  .nav a { white-space: nowrap; }
  .who .name { display: none; }
  main { padding-top: 28px; }
  .hero { grid-template-columns: 1fr; gap: 24px; padding-top: 4px; }
  .sonar { max-width: 200px; order: -1; justify-self: start; }
  .decks, .plans { grid-template-columns: 1fr; }
  .reader, .cols { grid-template-columns: 1fr; gap: 28px; }
  .side { position: static; }
  .dive::before { left: 62px; }
  .dive li { grid-template-columns: 50px 26px 1fr; gap: 0 10px; }
  .unit-card { padding: 14px 8px; }
  .routes table, .routes tbody, .routes tr, .routes td { display: block; }
  .routes thead { display: none; }
  .routes tr { border-bottom: 1px solid var(--line); padding: 10px 0; }
  .routes td { border: 0; padding: 2px 0; }
  .routes td:first-child { font-weight: 500; }
}