:root {
  --paper: #f5f7fa;
  --surface: #ffffff;
  --ink: #1e2a3d;
  --muted: #5d6b82;
  --line: #d9dfe8;
  --red: #c23b32;
  --blue: #1f4e99;
  --ok: #2f7a4b;
  --wait: #9a5f0c;
  --mark: #ffe9a8;
  --focus: #1f4e99;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --paper: #131923;
    --surface: #1b2330;
    --ink: #e6ebf2;
    --muted: #9ba7b9;
    --line: #2c3646;
    --red: #e0675e;
    --blue: #7ea6ec;
    --ok: #6fc38f;
    --wait: #e2a854;
    --mark: #5a4a12;
    --focus: #7ea6ec;
  }
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 15px/1.6 system-ui, -apple-system, "Segoe UI", "Noto Sans TC", "PingFang TC", "Microsoft JhengHei", sans-serif;
}
a { color: var(--blue); }
code, pre { font-family: ui-monospace, "SF Mono", Menlo, Consolas, monospace; font-size: 13px; }
:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }

/* The one bold element: an air-mail envelope edge. */
.airmail {
  height: 8px;
  background: repeating-linear-gradient(-45deg,
    var(--red) 0 14px, transparent 14px 22px, var(--blue) 22px 36px, transparent 36px 44px);
}

main { max-width: 960px; margin: 0 auto; padding: 16px 16px 48px; }

/* Header */
.top {
  max-width: 960px; margin: 0 auto; padding: 14px 16px 0;
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
}
.brand { color: var(--ink); text-decoration: none; font-weight: 700; font-size: 20px; letter-spacing: -0.01em; }
.top form { margin: 0; }

/* Buttons and inputs */
button {
  font: inherit; font-weight: 600; cursor: pointer;
  background: var(--blue); color: #fff; border: 0; border-radius: 6px; padding: 8px 16px;
}
@media (prefers-color-scheme: dark) { button { color: #0f1520; } }
button.quiet { background: transparent; color: var(--muted); border: 1px solid var(--line); }
button.quiet:hover { color: var(--ink); }
input, select {
  font: inherit; color: var(--ink); background: var(--surface);
  border: 1px solid var(--line); border-radius: 6px; padding: 0 10px; width: 100%; min-width: 0;
  height: 40px; line-height: 38px;
}
input[type=search] { -webkit-appearance: none; appearance: none; }
label { display: block; font-size: 13px; color: var(--muted); margin-bottom: 4px; }

/* Login */
.login {
  max-width: 360px; margin: 10vh auto 0; background: var(--surface);
  border: 1px solid var(--line); border-radius: 10px; padding: 28px 24px;
}
.login h1 { margin: 0 0 4px; font-size: 26px; letter-spacing: -0.02em; }
.login form { display: grid; gap: 6px; }
.login label { margin-top: 10px; }
.login button { margin-top: 18px; padding: 10px; }
#otp { letter-spacing: 0.3em; font-variant-numeric: tabular-nums; }
.note { color: var(--muted); margin: 0 0 8px; }
.error { color: var(--red); font-weight: 600; margin: 12px 0 0; }

/* Filters */
.filters {
  display: flex; flex-wrap: wrap; align-items: flex-end; gap: 12px;
  background: var(--surface); border: 1px solid var(--line); border-radius: 10px; padding: 14px;
}
.field { flex: 0 1 170px; }
.field.grow { flex: 1 1 240px; }
.actions { display: flex; align-items: center; gap: 14px; }
.reset { font-size: 14px; color: var(--muted); }

.summary { color: var(--muted); font-size: 14px; margin: 18px 2px 8px; font-variant-numeric: tabular-nums; }
.empty { margin: 32px 2px; color: var(--muted); }

/* Messages: a ledger, not a card grid. */
.msgs { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--line); }
.msg { padding: 14px 2px 12px; border-bottom: 1px solid var(--line); }
.meta { display: flex; flex-wrap: wrap; align-items: center; gap: 6px 12px; font-size: 14px; }
.meta time { color: var(--muted); font-variant-numeric: tabular-nums; }
.route b { font-weight: 650; }
.arrow { color: var(--red); margin: 0 6px; }
.body {
  margin: 6px 0 4px; white-space: pre-wrap; overflow-wrap: anywhere;
  display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden;
}
mark { background: var(--mark); color: inherit; border-radius: 2px; padding: 0 1px; }

.chip {
  font-size: 12px; font-weight: 600; border-radius: 999px; padding: 1px 9px;
  border: 1px solid currentColor;
}
.chip.ok { color: var(--ok); }
.chip.sent { color: var(--blue); }
.chip.wait { color: var(--wait); }
.chip.kind { color: var(--red); }

details summary { cursor: pointer; color: var(--muted); font-size: 13px; width: fit-content; }
details[open] summary { margin-bottom: 8px; }
dl { display: grid; grid-template-columns: max-content 1fr; gap: 2px 14px; margin: 0 0 10px; font-size: 13px; }
dt { color: var(--muted); }
dd { margin: 0; overflow-wrap: anywhere; }
pre {
  margin: 0; padding: 12px; background: var(--paper); border: 1px solid var(--line); border-radius: 6px;
  overflow-x: auto; white-space: pre-wrap; overflow-wrap: anywhere;
}

/* Pager */
.pager { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 22px; font-variant-numeric: tabular-nums; }
.pager a, .pager span {
  min-width: 38px; text-align: center; padding: 6px 10px; border-radius: 6px; text-decoration: none;
  border: 1px solid var(--line); background: var(--surface);
}
.pager .cur { background: var(--ink); color: var(--paper); border-color: var(--ink); font-weight: 700; }
.pager .off { color: var(--muted); opacity: .55; }
.pager .gap { border: 0; background: none; min-width: 0; }

@media (max-width: 600px) {
  .field, .field.grow { flex: 1 1 100%; }
  .actions { width: 100%; justify-content: space-between; }
}

/* Agent setup instructions (login page) */
.setup {
  max-width: 640px; margin: 28px auto 0; padding: 20px 24px;
  border: 1px solid var(--line); border-radius: 10px; background: var(--surface);
  font-size: 14px; line-height: 1.6;
}
.setup h2 { margin: 0 0 8px; font-size: 17px; }
.setup ol { padding-left: 20px; margin: 10px 0; }
.setup li { margin: 8px 0; }
.setup pre {
  margin: 6px 0 2px; padding: 10px 12px; overflow-x: auto;
  background: var(--paper); border: 1px solid var(--line); border-radius: 6px;
}
.setup .rules { color: var(--muted); margin: 10px 0 0; }

/* Navigation */
.nav { display: flex; gap: 16px; margin-right: auto; margin-left: 20px; font-size: 15px; }
.nav a { color: var(--muted); text-decoration: none; padding: 4px 0; }
.nav a:hover { color: var(--ink); }
.nav a[aria-current="page"] { color: var(--ink); font-weight: 650; border-bottom: 2px solid var(--red); }

/* Agent admin */
.admin h1 { font-size: 22px; margin: 8px 0 14px; }
.admin h2 { font-size: 16px; margin: 0 0 8px; }
.admin .notice { color: var(--ok); font-weight: 600; margin: 0 0 12px; }
.admin .error { margin: 0 0 12px; }
.table-wrap { overflow-x: auto; margin: 0 0 12px; }
.admin table { width: 100%; border-collapse: collapse; font-size: 14px; font-variant-numeric: tabular-nums; }
.admin th, .admin td { text-align: left; padding: 8px 10px; border-bottom: 1px solid var(--line); white-space: nowrap; }
.admin th { color: var(--muted); font-weight: 600; }
.admin-forms { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 16px; margin: 18px 0; }
.admin-forms form {
  display: grid; gap: 6px; align-content: start; padding: 18px;
  background: var(--surface); border: 1px solid var(--line); border-radius: 10px;
}
.admin-forms label { margin-top: 6px; }
.admin-forms button { margin-top: 12px; padding: 9px; }
.hint { color: var(--muted); font-size: 13px; margin: 0; }
button.danger { background: var(--red); }
.secret { width: 100%; font-family: ui-monospace, "SF Mono", Menlo, Consolas, monospace; font-size: 14px; }
.admin ol { padding-left: 20px; }
.admin pre {
  margin: 6px 0; padding: 10px 12px; overflow-x: auto;
  background: var(--paper); border: 1px solid var(--line); border-radius: 6px;
}