:root { --ink: #172e46; --teal: #216d73; --text: #34475b; --muted: #627082; --bg: #f2f6f8; --line: #dbe2e8; --warn: #775720; --warn-bg: #f5eee1; --danger: #c0392b; }
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--text); font-family: "Noto Sans TC", "Source Han Sans TC", "Microsoft JhengHei", system-ui, sans-serif; line-height: 1.6; }
[hidden] { display: none !important; }
.wrap { max-width: 880px; margin: 0 auto; padding: 16px; }
header.bar { display: flex; flex-wrap: wrap; gap: 8px 12px; align-items: center; justify-content: space-between; margin-bottom: 16px; }
h1 { margin: 0; color: var(--ink); font-size: 1.35rem; }
h2 { margin: 0 0 12px; color: var(--ink); font-size: 1.1rem; }
h3 { margin: 0 0 6px; color: var(--teal); font-size: 1rem; }
.card { background: #fff; border: 1px solid var(--line); border-radius: 12px; padding: 20px; margin-bottom: 16px; }
.row { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
label { display: block; font-size: .9rem; color: var(--muted); margin: 10px 0 4px; }
input, textarea, select { font: inherit; color: var(--text); border: 1px solid var(--line); border-radius: 8px; padding: 8px 10px; background: #fff; }
textarea { width: 100%; resize: vertical; min-height: 64px; }
input:focus, textarea:focus, select:focus { outline: 2px solid var(--teal); outline-offset: 1px; }
button { font: inherit; border: 1px solid var(--ink); border-radius: 8px; padding: 8px 14px; background: #fff; color: var(--ink); cursor: pointer; }
button.primary { background: var(--ink); color: #fff; }
button.danger { border-color: var(--danger); color: var(--danger); }
button:disabled { opacity: .5; cursor: default; }
.muted { color: var(--muted); font-size: .9rem; }
.pill { display: inline-block; padding: 2px 10px; border-radius: 999px; font-size: .85rem; background: var(--bg); color: var(--muted); }
.pill.open { background: #e3f1f1; color: var(--teal); }
.pill.makeup { background: var(--warn-bg); color: var(--warn); }
.notice { background: var(--warn-bg); color: var(--warn); border-radius: 8px; padding: 8px 12px; margin-top: 12px; }
.error { color: var(--danger); margin-top: 8px; min-height: 1.6em; }
.question { border-top: 1px solid var(--line); padding-top: 14px; margin-top: 14px; }
.link-box { display: grid; grid-template-columns: 1fr auto; gap: 16px; align-items: center; }
.code { font-size: 2rem; font-weight: 700; letter-spacing: .15em; color: var(--ink); }
.url { word-break: break-all; color: var(--teal); }
#qr-small canvas, #qr-small img { width: 120px; height: 120px; }
.overlay { position: fixed; inset: 0; background: #fff; display: grid; place-items: center; text-align: center; z-index: 10; padding: 16px; }
.overlay .code { font-size: 4rem; }
#qr-big canvas, #qr-big img { width: min(70vh, 80vw); height: auto; margin: 0 auto; }
@media (max-width: 560px) { .link-box { grid-template-columns: 1fr; } }

/* Student page */
.wrap.narrow { max-width: 560px; }
.student input { width: 100%; }
button.wide { width: 100%; padding: 12px; }
.row.between { justify-content: space-between; flex-wrap: nowrap; }
.notice-list { padding-left: 1.2em; margin: 0 0 16px; }
.notice-list li { margin-bottom: 6px; }
.chat-head { display: flex; justify-content: space-between; align-items: center; gap: 8px; position: sticky; top: 0; background: var(--bg); padding: 8px 0; z-index: 1; }
#log, #done-log { display: flex; flex-direction: column; gap: 10px; margin-bottom: 12px; }
.q-head { background: #fff; border: 1px solid var(--line); border-left: 4px solid var(--teal); border-radius: 8px; padding: 10px 12px; color: var(--ink); }
.q-head .muted { display: block; }
.bubble { max-width: 88%; padding: 10px 12px; border-radius: 12px; white-space: pre-wrap; word-break: break-word; }
.bubble.student { align-self: flex-end; background: var(--ink); color: #fff; border-bottom-right-radius: 4px; }
.bubble.ai { align-self: flex-start; background: #fff; border: 1px solid var(--line); border-bottom-left-radius: 4px; }
.bubble.pending { color: var(--muted); font-style: italic; }
.answer-box { position: sticky; bottom: 0; background: var(--bg); padding: 8px 0 12px; }
.answer-box textarea { min-height: 96px; font-size: 16px; }
details { margin-top: 16px; }
summary { cursor: pointer; color: var(--teal); }

/* Teacher results */
.stats h3 { margin-top: 14px; }
.stat { display: grid; grid-template-columns: minmax(0, 1fr) 120px 48px; gap: 10px; align-items: center; margin: 4px 0; font-size: .92rem; }
.stat-bar { height: 10px; background: var(--bg); border-radius: 999px; overflow: hidden; }
.stat-bar span { display: block; height: 100%; background: var(--teal); }
.stat-count { text-align: right; color: var(--muted); }
.analysis { background: #f4f9f9; border: 1px solid var(--line); border-radius: 10px; padding: 14px 16px; margin: 12px 0; }
.analysis h4 { margin: 12px 0 4px; color: var(--ink); }
.analysis ul { margin: 0; padding-left: 1.2em; }
.analysis li { margin-bottom: 6px; }
.table-wrap { overflow-x: auto; margin-top: 16px; }
#results-table { width: 100%; border-collapse: collapse; font-size: .92rem; }
#results-table th, #results-table td { text-align: left; padding: 8px; border-bottom: 1px solid var(--line); vertical-align: top; }
#results-table th { color: var(--muted); font-weight: 500; white-space: nowrap; }
.result-row { cursor: pointer; }
.result-row:hover, .result-row:focus { background: var(--bg); outline: none; }
.result-detail td { background: #fafcfd; }
.detail p { margin: 4px 0; }
.dialogue { display: flex; flex-direction: column; gap: 8px; margin: 10px 0; }
@media (max-width: 560px) { .stat { grid-template-columns: 1fr 80px 40px; } }
.mistake { background: #fff; border: 1px solid var(--line); border-left: 4px solid var(--warn); border-radius: 8px; padding: 10px 12px; margin: 8px 0; }
.mistake p { margin: 4px 0; }
.mistake details { margin-top: 6px; }
.mistake-head { display: flex; justify-content: space-between; gap: 8px; align-items: baseline; }
.mistake-head .pill { background: var(--warn-bg); color: var(--warn); white-space: nowrap; }
.class-feedback { background: #fff; border: 1px solid var(--line); border-radius: 8px; padding: 10px 12px; margin-bottom: 8px; white-space: pre-wrap; }