:root {
  color-scheme: light dark;
  --bg: #fff; --fg: #1d1d1f; --muted: #6e6e73; --line: #e5e5ea; --sel: #e8f0fe; --accent: #0a66d8; --err: #c4281c;
  font: 15px/1.45 -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
}
@media (prefers-color-scheme: dark) {
  :root { --bg: #1c1c1e; --fg: #f2f2f7; --muted: #98989d; --line: #38383a; --sel: #23324a; --accent: #4c9cff; --err: #ff6b5e; }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--fg); }
a { color: var(--accent); }
button, .button {
  font: inherit; color: var(--fg); background: transparent; border: 1px solid var(--line);
  border-radius: 6px; padding: 4px 12px; cursor: pointer; text-decoration: none; display: inline-block;
}
button.primary, .button.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
kbd { font: 11px ui-monospace, monospace; opacity: .7; }
.error { color: var(--err); }
.note, .meta, .date { color: var(--muted); }

.login { max-width: 360px; margin: 20vh auto; text-align: center; }

header { display: flex; align-items: center; gap: 16px; padding: 8px 16px; border-bottom: 1px solid var(--line); flex-wrap: wrap; }
header form { margin: 0; }
header .user { font-weight: 600; }
header .accounts { color: var(--muted); display: flex; gap: 8px; flex: 1; font-size: 13px; }

.app { display: grid; grid-template-columns: minmax(280px, 380px) 1fr; height: calc(100vh - 49px); }
.list { border-right: 1px solid var(--line); overflow-y: auto; padding: 8px 0; }
.group h2, .group summary { font-size: 12px; text-transform: uppercase; letter-spacing: .04em; color: var(--muted); margin: 12px 16px 4px; cursor: default; }
.group summary { cursor: pointer; }
.list ul { list-style: none; margin: 0; padding: 0; }
.item { display: grid; grid-template-columns: 1fr auto; gap: 0 8px; padding: 8px 16px; color: inherit; text-decoration: none; border-left: 3px solid transparent; }
.item:hover { background: var(--sel); }
.item.sel { background: var(--sel); border-left-color: var(--accent); }
.item .from { font-weight: 600; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.item .date { font-size: 12px; }
.item .subject, .item .summary { grid-column: 1 / -1; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.item .summary { color: var(--muted); font-size: 13px; }

.panel { overflow-y: auto; padding: 16px 24px; }
.panel.empty { display: grid; place-items: center; color: var(--muted); }
.panel h1 { font-size: 20px; margin: 0 0 4px; }
.panel .lead { font-size: 16px; }
.panel details summary { cursor: pointer; color: var(--muted); }
.panel pre.body { white-space: pre-wrap; word-wrap: break-word; font: inherit; background: color-mix(in srgb, var(--line) 35%, transparent); padding: 12px; border-radius: 6px; max-height: 40vh; overflow-y: auto; }
.panel textarea { width: 100%; font: inherit; color: inherit; background: transparent; border: 1px solid var(--line); border-radius: 6px; padding: 10px; margin-top: 12px; resize: vertical; }
.buttons { display: flex; gap: 8px; margin-top: 8px; }

#undo { position: fixed; left: 50%; bottom: 24px; transform: translateX(-50%); background: var(--fg); color: var(--bg); padding: 10px 16px; border-radius: 8px; display: flex; gap: 12px; align-items: center; }
#undo[hidden] { display: none; }
#undo button { color: var(--bg); border-color: var(--bg); }

@media (max-width: 720px) { .app { grid-template-columns: 1fr; height: auto; } .list { border-right: 0; } }