:root {
  --bg: #f4f6f8;
  --panel: #ffffff;
  --panel2: #eef1f5;
  --border: #e2e7ee;
  --text: #1a2330;
  --muted: #6b7a8d;
  --accent: #D52B1E;
  --accent2: #2563eb;
  --ok: #16a34a;
  --warn: #d97706;
  --radius: 12px;
  --font: 'DM Sans', system-ui, sans-serif;
}
* { box-sizing: border-box; }
html, body, #root { height: 100%; margin: 0; }
body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
}
.app { display: grid; grid-template-columns: 320px 1fr 360px; height: 100%; }
@media (max-width: 960px) {
  .app { grid-template-columns: 1fr; }
  .col-list, .col-thread { display: none; }
  .app.show-list .col-list { display: flex; }
  .app.show-thread .col-thread { display: flex; }
  .app.show-detail .col-detail { display: flex; }
}
.col-list, .col-thread, .col-detail {
  display: flex; flex-direction: column; min-height: 0;
  border-right: 1px solid var(--border);
}
.col-detail { border-right: 0; }
.top {
  padding: 14px 16px; border-bottom: 1px solid var(--border);
  display: flex; align-items: center; gap: 10px;
}
.brand { font-weight: 700; letter-spacing: -0.02em; }
.brand span { color: var(--accent); }
.badge {
  font-size: 11px; padding: 2px 8px; border-radius: 999px;
  background: var(--panel2); color: var(--muted);
}
.badge.ok { background: rgba(34,197,94,.15); color: var(--ok); }
.badge.warn { background: rgba(245,158,11,.15); color: var(--warn); }
.scroll { flex: 1; overflow: auto; }
.msg-item {
  padding: 12px 16px; border-bottom: 1px solid var(--border);
  cursor: pointer; transition: background .15s;
}
.msg-item:hover, .msg-item.active { background: var(--panel); }
.msg-item .from { font-weight: 600; font-size: 14px; }
.msg-item .subj { font-size: 13px; color: var(--muted); margin-top: 2px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.msg-item .meta { font-size: 11px; color: var(--muted); margin-top: 4px; display: flex; justify-content: space-between; }
.empty {
  padding: 40px 20px; text-align: center; color: var(--muted); font-size: 14px;
}
.detail-head { padding: 16px 20px; border-bottom: 1px solid var(--border); }
.detail-head h1 { margin: 0 0 8px; font-size: 18px; font-weight: 700; }
.detail-body { padding: 20px; overflow: auto; flex: 1; font-size: 14px; line-height: 1.55; }
.detail-body img { max-width: 100%; }
.reply {
  border-top: 1px solid var(--border); padding: 12px 16px;
  display: flex; flex-direction: column; gap: 8px;
}
.reply textarea {
  width: 100%; min-height: 90px; resize: vertical;
  background: var(--panel2); border: 1px solid var(--border);
  border-radius: var(--radius); color: var(--text);
  padding: 10px 12px; font-family: inherit; font-size: 14px;
}
.btn {
  appearance: none; border: 0; border-radius: 10px;
  padding: 10px 14px; font-weight: 600; font-size: 13px;
  cursor: pointer; font-family: inherit;
}
.btn-primary { background: var(--accent); color: white; }
.btn-primary:disabled { opacity: .5; cursor: not-allowed; }
.btn-ghost { background: transparent; color: var(--muted); }
.login {
  min-height: 100%; display: grid; place-items: center; padding: 24px;
  background: radial-gradient(ellipse at top, #e8eef6, var(--bg));
}
.login-card {
  width: min(420px, 100%); background: var(--panel);
  border: 1px solid var(--border); border-radius: 16px; padding: 28px;
  box-shadow: 0 8px 28px rgba(26, 35, 48, 0.06);
}
.login-card h1 { margin: 0 0 8px; font-size: 22px; }
.login-card p { color: var(--muted); font-size: 14px; margin: 0 0 20px; }
.login-card input {
  width: 100%; padding: 12px 14px; border-radius: 10px;
  border: 1px solid var(--border); background: var(--panel2);
  color: var(--text); margin-bottom: 12px; font-family: inherit;
}
.err { color: #dc2626; font-size: 13px; margin-bottom: 10px; }
.mb-list { padding: 8px; }
.mb-chip {
  display: block; width: 100%; text-align: left;
  padding: 10px 12px; margin-bottom: 4px;
  background: transparent; border: 1px solid transparent;
  border-radius: 10px; color: var(--text); cursor: pointer; font-family: inherit;
}
.mb-chip:hover, .mb-chip.active { background: var(--panel2); border-color: var(--border); }
.mb-chip small { color: var(--muted); display: block; font-size: 11px; margin-top: 2px; }