:root { --bg: #F2F6F6; --surface: #FFFFFF; --ink: #15272B; --muted: #5D7177; --accent: #0B7C8A; --line: #D5DFE1; --danger: #B4232C; --tint: #E6F3F5; }
* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--bg); color: var(--ink); font: 16px/1.6 "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif; }
.wrap { max-width: 720px; margin: 0 auto; padding: 0 16px 48px; }
h1 { font-size: 22px; margin: 20px 0 8px; }
h2.section { font-size: 17px; color: var(--accent); margin: 28px 0 10px; }
.intro, .hint { color: var(--muted); }
.hint { font-size: 14px; margin: 4px 0 8px; }
.rules { margin: 0 0 18px; padding-left: 20px; font-size: 15px; }
.rules li { margin: 4px 0; }
.points { margin: 2px 0 8px; padding-left: 20px; color: var(--muted); font-size: 14px; line-height: 1.55; }
.points li { margin: 2px 0; }
.card { background: var(--surface); border: 1px solid var(--line); border-radius: 12px; padding: 14px 16px; margin: 0 0 12px; }
.q-title { display: block; font-weight: 600; margin-bottom: 4px; }
.num { color: var(--accent); margin-right: 6px; }
.req { font-size: 12px; font-weight: 400; color: var(--muted); margin-left: 8px; }
input[type=text], textarea { width: 100%; font: inherit; font-size: 16px; color: var(--ink); background: #fff; border: 1px solid var(--line); border-radius: 8px; padding: 10px 12px; margin-top: 6px; }
textarea { display: block; resize: none; min-height: 88px; overflow: hidden; }
::placeholder { color: #9AABAF; }
input:focus, textarea:focus, button:focus, a:focus, .btn:focus-within { outline: 3px solid rgba(11, 124, 138, .35); outline-offset: 1px; border-color: var(--accent); }
.chip { display: inline-flex; align-items: center; gap: 6px; margin-top: 10px; padding: 5px 12px; border: 1px solid var(--line); border-radius: 999px; font-size: 14px; color: var(--muted); cursor: pointer; user-select: none; }
.chip input { margin: 0; accent-color: var(--accent); }
.chip.on { border-color: var(--accent); color: var(--accent); background: var(--tint); }
.btn { display: inline-block; font: inherit; font-size: 16px; padding: 12px 20px; border-radius: 10px; border: 1px solid var(--accent); cursor: pointer; text-align: center; }
.btn-primary { width: 100%; background: var(--accent); color: #fff; margin-top: 8px; }
.btn-primary:disabled { opacity: .6; cursor: default; }
.btn-secondary { background: #fff; color: var(--accent); }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }
.error { color: var(--danger); font-size: 14px; margin: 8px 0 0; white-space: pre-line; }
.done { color: var(--accent); font-weight: 600; text-align: center; margin-top: 12px; }
.progress { position: sticky; top: 0; z-index: 2; background: rgba(242, 246, 246, .96); border-bottom: 1px solid var(--line); font-size: 14px; color: var(--muted); }
.progress .wrap { display: flex; justify-content: space-between; padding: 8px 16px; }
.files { list-style: none; padding: 0; margin: 10px 0 0; }
.files li { display: flex; align-items: center; gap: 10px; padding: 8px 0; border-top: 1px solid var(--line); font-size: 14px; }
.files .fname { flex: 1; word-break: break-all; }
.files .fsize { color: var(--muted); white-space: nowrap; }
.link { background: none; border: 0; color: var(--danger); font: inherit; font-size: 14px; cursor: pointer; padding: 4px; }
/* admin */
.wide { max-width: none; }
.meta { color: var(--muted); }
.meta a { color: var(--accent); }
.table-wrap { overflow-x: auto; background: var(--surface); border: 1px solid var(--line); border-radius: 12px; }
table { border-collapse: collapse; font-size: 14px; }
th, td { border-bottom: 1px solid var(--line); padding: 8px 10px; vertical-align: top; text-align: left; }
th { background: var(--tint); position: sticky; top: 0; }
th.qh { min-width: 280px; max-width: 360px; font-weight: 600; }
td.ans { min-width: 280px; max-width: 360px; white-space: pre-wrap; word-break: break-word; }
.sticky { position: sticky; left: 0; background: var(--surface); }
th.sticky { background: var(--tint); z-index: 1; }
.nowrap { white-space: nowrap; }
.badge { display: inline-block; font-size: 12px; color: var(--accent); border: 1px solid var(--accent); border-radius: 999px; padding: 0 8px; margin-right: 6px; line-height: 1.5; }
.admin h2 { font-size: 18px; margin: 28px 0 10px; }
.admin h3 { font-size: 15px; margin: 0 0 8px; }
.admin p.ans { white-space: pre-wrap; margin: 0 0 10px; padding-bottom: 10px; border-bottom: 1px solid var(--line); }
.admin p.ans:last-child { border-bottom: 0; margin-bottom: 0; padding-bottom: 0; }