:root {
  --ink: #1c1917;
  --paper: #faf7f2;
  --panel: #ffffff;
  --border: #e5ded3;
  --accent: #7c2d12;
  --accent-soft: #fbeae0;
  --muted: #78716c;
  --error-bg: #fef2f2;
  --error-ink: #9f1239;
  --radius: 10px;
  --maxw: 760px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, serif;
  color: var(--ink);
  background: var(--paper);
  line-height: 1.6;
}

main { max-width: var(--maxw); margin: 0 auto; padding: 1.5rem 1.25rem 3rem; }

.site-header {
  display: flex; align-items: center; justify-content: space-between;
  gap: 1rem; flex-wrap: wrap;
  max-width: var(--maxw); margin: 0 auto; padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border);
}
.brand { font-size: 1.25rem; font-weight: 700; text-decoration: none; color: var(--ink); }
.brand-mark {
  display: inline-grid; place-items: center;
  width: 1.7rem; height: 1.7rem; border-radius: 6px;
  background: var(--accent); color: #fff; font-size: 1rem; vertical-align: -0.35rem;
}
.site-header nav { display: flex; align-items: center; gap: 1.1rem; }
.site-header nav a { color: var(--accent); text-decoration: none; }
.inline { display: inline; margin: 0; }
.linkbtn { background: none; border: none; color: var(--accent); cursor: pointer; font: inherit; padding: 0; }

footer { text-align: center; color: var(--muted); font-size: .85rem; padding: 2rem 1rem; }

h1 { font-size: 1.6rem; margin: 0 0 .5rem; }
.muted { color: var(--muted); }
.lede { font-size: 1.05rem; }
.fineprint { font-size: .85rem; color: var(--muted); }

.panel, .auth-card, .result {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
}
.auth-card { max-width: 420px; margin: 2rem auto; }

label { display: block; margin: .9rem 0 .3rem; font-weight: 600; }
label .muted { font-weight: 400; }
input, textarea, select {
  width: 100%; padding: .6rem .7rem; font: inherit;
  border: 1px solid var(--border); border-radius: 8px; background: #fff; color: var(--ink);
}
textarea { resize: vertical; }
.stack > * + * { margin-top: .4rem; }
.row { display: flex; gap: .75rem; align-items: flex-end; flex-wrap: wrap; margin-top: 1rem; }
.row > label { margin: 0; flex: 1 1 180px; }

.btn {
  display: inline-block; padding: .6rem 1.1rem; font: inherit; cursor: pointer;
  border: 1px solid var(--accent); border-radius: 8px;
  background: var(--accent); color: #fff;
}
.btn:hover { background: #641f0c; }
.btn[disabled] { opacity: .55; cursor: progress; }
.btn-ghost { background: #fff; color: var(--accent); }
.btn-ghost:hover { background: var(--accent-soft); }
.btn-google { width: 100%; background: #fff; color: var(--ink); border-color: var(--border); }
.btn-google:hover { background: #f5f0e8; }

.divider { display: flex; align-items: center; gap: .8rem; color: var(--muted); margin: 1rem 0; }
.divider::before, .divider::after { content: ""; flex: 1; height: 1px; background: var(--border); }

.styleset { border: none; padding: 0; margin: 1rem 0 0; }
.styleset legend { font-weight: 600; padding: 0; margin-bottom: .4rem; }
.segmented { display: flex; gap: .5rem; flex-wrap: wrap; }
.seg {
  flex: 1 1 150px; margin: 0; display: block; cursor: pointer;
  border: 1px solid var(--border); border-radius: 8px; padding: .55rem .7rem;
  font-weight: 400; background: #fff; transition: border-color .12s, background .12s;
}
.seg:hover { background: var(--accent-soft); }
.seg input { position: absolute; opacity: 0; width: 0; height: 0; }
.seg:has(input:checked) { border-color: var(--accent); background: var(--accent-soft); box-shadow: inset 0 0 0 1px var(--accent); }
.seg:has(input:focus-visible) { outline: 2px solid var(--accent); outline-offset: 2px; }
.seg-name { display: block; font-weight: 700; }
.seg-blurb { display: block; font-size: .8rem; color: var(--muted); }

.pill {
  display: inline-block; padding: .05rem .5rem; border-radius: 999px;
  background: var(--accent-soft); color: var(--accent); font-size: .78rem; white-space: nowrap;
}

.demos { margin-top: 1rem; }
.demos summary { cursor: pointer; color: var(--accent); }
.chip {
  display: inline-block; margin: .5rem .4rem 0 0; padding: .35rem .7rem;
  border: 1px solid var(--border); border-radius: 999px; background: #fff; cursor: pointer; font: inherit;
}
.chip:hover { background: var(--accent-soft); }

.error { background: var(--error-bg); color: var(--error-ink); border: 1px solid #f6d5d5;
  border-radius: 8px; padding: .7rem .9rem; margin-top: 1rem; }

.result { margin-top: 1.5rem; }
.result-head { display: flex; align-items: baseline; justify-content: space-between; gap: 1rem; }
.tags { font-size: .8rem; color: var(--muted); text-transform: lowercase; }

/* multi-option switcher (pure CSS via :has) */
.opt-radio { position: absolute; opacity: 0; width: 0; height: 0; }
.opt-tabs { display: flex; gap: .4rem; margin: .8rem 0 1rem; flex-wrap: wrap; }
.opt-tab {
  cursor: pointer; padding: .35rem .9rem; border: 1px solid var(--border);
  border-radius: 999px; font-size: .9rem; background: #fff; user-select: none;
}
.opt-tab:hover { background: var(--accent-soft); }
.opts:has(#opt1:checked) [for="opt1"],
.opts:has(#opt2:checked) [for="opt2"],
.opts:has(#opt3:checked) [for="opt3"] { background: var(--accent); color: #fff; border-color: var(--accent); }
.opt-panel { display: none; }
.opts:has(#opt1:checked) .opt-panel[data-i="1"],
.opts:has(#opt2:checked) .opt-panel[data-i="2"],
.opts:has(#opt3:checked) .opt-panel[data-i="3"] { display: block; }
.draft { white-space: pre-wrap; font-size: 1.08rem; background: var(--accent-soft);
  border-radius: 8px; padding: 1rem; }
.lesson { display: grid; grid-template-columns: max-content 1fr; gap: .3rem .9rem; margin: .5rem 0 1rem; }
.lesson dt { font-weight: 700; color: var(--muted); }
.lesson dd { margin: 0; }
[lang="zh"] { font-family: "Songti SC", "STSong", "Noto Serif CJK SC", serif; }

.htmx-indicator { display: none; }
.htmx-request .htmx-indicator, .htmx-request.htmx-indicator { display: block; }

.history-item { border: 1px solid var(--border); border-radius: 8px; padding: .5rem .9rem; margin-top: .6rem; }
.history-item summary { cursor: pointer; display: flex; gap: .7rem; align-items: baseline; flex-wrap: wrap; }
.history-item[open] summary { border-bottom: 1px solid var(--border); padding-bottom: .6rem; margin-bottom: .3rem; }
.history-item .when { color: var(--muted); font-variant-numeric: tabular-nums; font-size: .85rem; }
.history-item .preview { color: var(--ink); flex: 1 1 60%; }
.history-item .label { font-weight: 700; color: var(--muted); margin: .9rem 0 .2rem; font-size: .82rem; text-transform: uppercase; letter-spacing: .02em; }
.history-item .hist-msg { white-space: pre-wrap; }
.history-item .draft { margin-top: .2rem; }
.history-item .lesson { margin: .6rem 0; font-size: .95rem; }
.alts { margin-top: .8rem; }
.alts summary { cursor: pointer; color: var(--accent); font-size: .9rem; }
.alt { border-left: 2px solid var(--border); padding-left: .8rem; margin-top: .7rem; }
.alt .draft { margin: .2rem 0; }
.hist-foot { display: flex; align-items: center; justify-content: space-between; gap: 1rem;
  margin-top: .8rem; padding-top: .6rem; border-top: 1px solid var(--border); }
.hist-foot form { margin: 0; }
.linkbtn.danger { color: var(--error-ink); }
.linkbtn.danger:hover { text-decoration: underline; }
.history-item.htmx-swapping { opacity: 0; transition: opacity .15s ease-out; }

@media (max-width: 480px) {
  .panel, .auth-card, .result { padding: 1.1rem; }
}