:root {
  --blue: #2563eb;
  --blue-d: #1d4ed8;
  --bg: #f1f5f9;
  --card: #ffffff;
  --line: #e2e8f0;
  --text: #0f172a;
  --muted: #64748b;
  --danger: #dc2626;
  --ok: #16a34a;
}
* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0; background: var(--bg); color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", sans-serif;
  font-size: 14px;
}
.center { display: flex; align-items: center; justify-content: center; min-height: 100vh; }
.muted { color: var(--muted); }
.danger { color: var(--danger); }
button {
  font: inherit; cursor: pointer; border: none; border-radius: 8px;
  padding: 8px 14px; background: var(--blue); color: #fff;
}
button:hover { background: var(--blue-d); }
button.ghost { background: #fff; color: var(--text); border: 1px solid var(--line); }
button.ghost:hover { background: #f8fafc; }
button.sm { padding: 4px 10px; font-size: 12px; border-radius: 6px; }
button.warn { background: var(--danger); }
input, select, textarea {
  font: inherit; padding: 9px 11px; border: 1px solid var(--line);
  border-radius: 8px; background: #fff; color: var(--text); width: 100%;
}
input:focus, select:focus, textarea:focus { outline: 2px solid #bfdbfe; border-color: var(--blue); }
label { display: block; font-size: 12px; color: var(--muted); margin: 10px 0 4px; }

/* 登录 */
.login-card {
  width: 340px; background: var(--card); border: 1px solid var(--line);
  border-radius: 16px; padding: 28px; box-shadow: 0 10px 30px rgba(0,0,0,.06);
}
.login-card h1 { margin: 0 0 4px; font-size: 22px; }
.login-card .sub { color: var(--muted); margin-bottom: 18px; }
.login-card button { width: 100%; margin-top: 16px; padding: 11px; }
.err { color: var(--danger); font-size: 13px; margin-top: 10px; min-height: 18px; }

/* 布局 */
.shell { display: flex; flex-direction: column; height: 100vh; }
.topbar {
  display: flex; align-items: center; gap: 14px; padding: 10px 16px;
  background: var(--card); border-bottom: 1px solid var(--line);
}
.topbar .brand { font-weight: 700; font-size: 16px; }
.topbar .tabs { display: flex; gap: 6px; }
.topbar .tabs button { background: transparent; color: var(--muted); padding: 6px 12px; }
.topbar .tabs button.active { background: #eff6ff; color: var(--blue); }
.topbar .spacer { flex: 1; }
.topbar .who { color: var(--muted); font-size: 13px; }
.badge { font-size: 11px; padding: 1px 7px; border-radius: 999px; background: #eef2ff; color: var(--blue); }
.badge.admin { background: #fef3c7; color: #b45309; }

.main { flex: 1; overflow: hidden; display: flex; }

/* 消息 */
.msg-wrap { flex: 1; display: flex; flex-direction: column; }
.msg-list { flex: 1; overflow-y: auto; padding: 16px; }
.msg {
  max-width: 70%; margin: 8px 0; padding: 9px 12px; border-radius: 12px;
  background: #fff; border: 1px solid var(--line); word-break: break-word;
}
.msg .meta { font-size: 11px; color: var(--muted); margin-bottom: 3px; }
.msg.mine { margin-left: auto; background: #eff6ff; border-color: #bfdbfe; }
.msg .title { font-weight: 600; }
.msg.cmd { background: #f0fdf4; border-color: #bbf7d0; }
.msg img { max-width: 220px; border-radius: 8px; display: block; margin-top: 6px; }
.msg a.file { color: var(--blue); }
.composer { border-top: 1px solid var(--line); padding: 10px 16px; background: var(--card); }
.composer .row { display: flex; gap: 8px; align-items: center; }
.composer textarea { resize: none; height: 40px; }
.composer .row2 { display: flex; gap: 8px; margin-top: 8px; flex-wrap: wrap; align-items: center; }
.chip { background: #f1f5f9; color: #334155; border: 1px solid var(--line); }
.target-sel { max-width: 220px; }

/* 用户管理 */
.users-wrap { flex: 1; overflow-y: auto; padding: 18px; }
table { width: 100%; border-collapse: collapse; background: #fff; border: 1px solid var(--line); border-radius: 10px; overflow: hidden; }
th, td { text-align: left; padding: 9px 12px; border-bottom: 1px solid var(--line); }
th { background: #f8fafc; color: var(--muted); font-weight: 600; font-size: 12px; }
tr:last-child td { border-bottom: none; }
.toolbar { display: flex; gap: 8px; margin-bottom: 14px; align-items: center; }
.toolbar h2 { margin: 0; font-size: 16px; flex: 1; }

/* 弹窗 */
.modal-bg { position: fixed; inset: 0; background: rgba(0,0,0,.35); display: flex; align-items: center; justify-content: center; }
.modal { width: 360px; background: #fff; border-radius: 14px; padding: 22px; }
.modal h3 { margin: 0 0 12px; }
.modal .actions { display: flex; gap: 8px; justify-content: flex-end; margin-top: 18px; }
.hidden { display: none !important; }