:root {
  --bg: #f6f4ef; --card: #ffffff; --ink: #2b2b28; --muted: #8a877e;
  --accent: #b3502d; --line: #e4e0d6; --mine: #eef3ec;
}
* { box-sizing: border-box; }
body { margin: 0; font: 15px/1.6 -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg); color: var(--ink); }
[hidden] { display: none !important; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: 10px; padding: 24px; }
.narrow { max-width: 360px; margin: 12vh auto; display: flex; flex-direction: column; gap: 12px; }
label { display: flex; flex-direction: column; gap: 4px; font-size: 13px; color: var(--muted); }
input, textarea { font: inherit; padding: 8px 10px; border: 1px solid var(--line); border-radius: 8px; background: #fff; }
button { font: inherit; padding: 8px 16px; border: 0; border-radius: 8px; background: var(--accent);
  color: #fff; cursor: pointer; }
button:hover { filter: brightness(1.08); }
.muted { color: var(--muted); font-size: 13px; }
.err { color: #a33; font-size: 13px; }
header { display: flex; align-items: center; gap: 16px; padding: 10px 20px;
  background: var(--card); border-bottom: 1px solid var(--line); position: sticky; top: 0; }
#channel-list { display: flex; gap: 8px; flex: 1; }
#channel-list a { text-decoration: none; color: var(--ink); padding: 4px 10px; border-radius: 999px; }
#channel-list a.active { background: var(--accent); color: #fff; }
#channel-list .badge { background: var(--accent); color: #fff; border-radius: 999px;
  font-size: 11px; padding: 0 6px; margin-left: 4px; }
main { max-width: 760px; margin: 0 auto; padding: 16px; display: flex; flex-direction: column; gap: 16px; }
.msg { background: var(--card); border: 1px solid var(--line); border-radius: 10px; padding: 12px 16px; }
.msg.mine { background: var(--mine); }
.msg .head { display: flex; gap: 8px; align-items: baseline; flex-wrap: wrap; }
.msg .head .from { font-weight: 600; }
.msg .head .to { color: var(--muted); font-size: 13px; }
.msg .head time { color: var(--muted); font-size: 12px; margin-left: auto; }
.msg .summary { margin: 6px 0; }
.msg .toggle { background: none; border: 0; color: var(--accent); cursor: pointer; padding: 0; font-size: 13px; }
.msg .body { border-top: 1px dashed var(--line); margin-top: 8px; padding-top: 8px; overflow-x: auto; }
.msg .body table { border-collapse: collapse; }
.msg .body td, .msg .body th { border: 1px solid var(--line); padding: 4px 8px; }
.msg .body pre { background: #f0ede6; padding: 8px; border-radius: 6px; overflow-x: auto; }
#composer { display: flex; flex-direction: column; gap: 8px; background: var(--card);
  border: 1px solid var(--line); border-radius: 10px; padding: 12px 16px; }
#composer textarea { min-height: 90px; resize: vertical; }
#to-row { display: flex; gap: 12px; font-size: 13px; color: var(--muted); flex-wrap: wrap; }
.row { display: flex; align-items: center; gap: 12px; }
.steps { max-width: 560px; margin: 6vh auto; display: flex; flex-direction: column; gap: 16px; }
.steps pre { background: #f0ede6; padding: 10px; border-radius: 8px; overflow-x: auto; white-space: pre-wrap; }
.dl { display: inline-block; margin: 4px 8px 4px 0; padding: 8px 14px; background: var(--accent);
  color: #fff; border-radius: 8px; text-decoration: none; }
.import-btn { padding: 8px 14px; border: 1px dashed var(--accent); border-radius: 8px;
  color: var(--accent); cursor: pointer; font-size: 13px; }
.import-btn:hover { background: #f7ede8; }
#composer textarea.dragging { border-color: var(--accent); background: #fbf6f0; }
#composer button[type=submit]:disabled { opacity: 0.4; cursor: not-allowed; }