:root {
  --bg: #0f1115;
  --bg2: #161a21;
  --bg3: #1d222b;
  --line: #262c37;
  --fg: #e6e9ef;
  --fg2: #9aa4b2;
  --acc: #4c8dff;
  --ok: #2ecc71;
  --err: #ff5f56;
  --warn: #f5a623;
  --radius: 10px;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; height: 100%; }
body {
  background: var(--bg);
  color: var(--fg);
  font: 14px/1.55 -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
        "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}
a { color: var(--acc); text-decoration: none; }
a:hover { text-decoration: underline; }
.mono { font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 12px; }
.muted { color: var(--fg2); }

/* ---------- buttons / inputs ---------- */
.btn {
  display: inline-block;
  padding: 7px 13px;
  border-radius: 8px;
  border: 1px solid var(--line);
  background: var(--bg3);
  color: var(--fg);
  cursor: pointer;
  font-size: 13px;
  line-height: 1.3;
  text-align: center;
}
.btn:hover { background: #242b36; text-decoration: none; }
.btn.primary { background: var(--acc); border-color: var(--acc); color: #fff; }
.btn.primary:hover { background: #3d7ce8; }
.btn.ghost { background: transparent; }
.btn.block { display: block; width: 100%; margin-bottom: 8px; }
.btn.tiny { padding: 3px 9px; font-size: 12px; }
.btn.danger { color: var(--err); border-color: #3a2224; }
.btn.danger:hover { background: #2a1a1c; }

input, select, textarea {
  width: 100%;
  padding: 9px 11px;
  margin: 4px 0 12px;
  border-radius: 8px;
  border: 1px solid var(--line);
  background: var(--bg2);
  color: var(--fg);
  font-size: 14px;
  font-family: inherit;
}
input:focus, select:focus, textarea:focus { outline: none; border-color: var(--acc); }
label { color: var(--fg2); font-size: 12.5px; display: block; margin-top: 6px; }

/* ---------- cards / alerts ---------- */
.card {
  background: var(--bg2);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px;
}
.alert { padding: 9px 12px; border-radius: 8px; margin: 10px 0; font-size: 13px; }
.alert.err { background: #2a1a1c; border: 1px solid #55272a; color: #ffb3ae; }
.alert.ok { background: #16281f; border: 1px solid #24503a; color: #9ff0c2; }
.alert.warn { background: #2a2415; border: 1px solid #554424; color: #f5d79a; }

/* ---------- login ---------- */
.login-wrap { min-height: 100%; display: flex; align-items: center; justify-content: center; padding: 32px 16px; }
.login-card { width: 100%; max-width: 430px; }
.brand { margin: 0 0 4px; font-size: 22px; letter-spacing: .5px; }
.sub { margin: 0 0 14px; color: var(--fg2); font-size: 12.5px; }
.hint { color: var(--fg2); font-size: 12px; margin: -6px 0 10px; }
.row2 { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.seg { display: flex; gap: 16px; margin: 6px 0 8px; }
.seg label { display: flex; align-items: center; gap: 6px; color: var(--fg); margin: 0; }
.seg input { width: auto; margin: 0; }
.adv { margin: 6px 0 14px; }
.adv summary { cursor: pointer; color: var(--fg2); font-size: 13px; margin-bottom: 6px; }
.login-card button[type=submit] { width: 100%; margin-top: 6px; }

/* ---------- layout ---------- */
.layout { display: grid; grid-template-columns: 250px 1fr; height: 100vh; }
.side {
  background: var(--bg2);
  border-right: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}
.side-head { padding: 14px 14px 10px; border-bottom: 1px solid var(--line); }
.who { font-size: 13px; word-break: break-all; }
.proto { color: var(--fg2); font-size: 11px; letter-spacing: 1px; margin-top: 2px; }
.folders { flex: 1; overflow-y: auto; padding: 8px; }
.folder {
  display: block;
  padding: 7px 10px;
  border-radius: 7px;
  color: var(--fg);
  font-size: 13px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.folder:hover { background: var(--bg3); text-decoration: none; }
.folder.active { background: #22304a; color: #cfe0ff; }
.side-foot { padding: 10px; border-top: 1px solid var(--line); }

.main { display: flex; flex-direction: column; overflow: hidden; }
.topbar {
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
  padding: 13px 20px; border-bottom: 1px solid var(--line); background: var(--bg2);
}
.topbar h2 { margin: 0; font-size: 15px; font-weight: 600; }
.subject-h { max-width: 70ch; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.search { display: flex; gap: 8px; margin: 0; }
.search input { margin: 0; width: 240px; }

/* ---------- list ---------- */
.list { flex: 1; overflow-y: auto; }
.item { display: flex; align-items: center; border-bottom: 1px solid var(--line); }
.item:hover { background: var(--bg2); }
.item.unread .subject { color: #fff; font-weight: 600; }
.item.unread { border-left: 3px solid var(--acc); }
.item-main { flex: 1; padding: 10px 18px; color: inherit; min-width: 0; }
.item-main:hover { text-decoration: none; }
.line1 { display: flex; justify-content: space-between; gap: 12px; }
.from { font-size: 13px; color: var(--fg); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.date { font-size: 12px; color: var(--fg2); white-space: nowrap; }
.line2 { display: flex; justify-content: space-between; gap: 12px; margin-top: 2px; }
.subject { font-size: 13px; color: #c3cbd8; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.size { font-size: 11px; color: var(--fg2); white-space: nowrap; }
.row-act { padding-right: 14px; }
.empty { padding: 46px; text-align: center; color: var(--fg2); }

.pager {
  display: flex; align-items: center; justify-content: space-between;
  padding: 10px 20px; border-top: 1px solid var(--line); background: var(--bg2);
}
.pager-btns { display: flex; gap: 8px; }

/* ---------- message ---------- */
.meta { padding: 14px 20px; border-bottom: 1px solid var(--line); font-size: 13px; }
.meta-row { display: flex; gap: 10px; padding: 2px 0; }
.meta-row b { color: var(--fg2); font-weight: 500; width: 82px; flex: none; }
.atts { padding: 12px 20px; border-bottom: 1px solid var(--line); font-size: 13px; }
.att-list { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 8px; }
.att {
  display: inline-flex; gap: 8px; align-items: center;
  padding: 6px 11px; border: 1px solid var(--line); border-radius: 20px;
  background: var(--bg2); color: var(--fg); font-size: 12.5px;
}
.att:hover { text-decoration: none; border-color: var(--acc); }
.att-size { color: var(--fg2); }
.body { flex: 1; overflow-y: auto; padding: 20px; background: #fff; color: #1a1a1a; }
.body pre.plain { white-space: pre-wrap; word-break: break-word; font: inherit; margin: 0; color: #1a1a1a; }
.body img { max-width: 100%; height: auto; }
.body table { max-width: 100%; border-collapse: collapse; }
.body a { color: #0b57d0; }
.body blockquote { border-left: 3px solid #ddd; margin: 0 0 0 6px; padding-left: 12px; color: #555; }

@media (max-width: 720px) {
  .layout { grid-template-columns: 1fr; height: auto; }
  .side { border-right: none; border-bottom: 1px solid var(--line); }
  .folders { max-height: 200px; }
  .search input { width: 130px; }
}