:root {
  color-scheme: light dark;
  --bg: #f5f1fb;
  --surface: rgba(255,255,255,.78);
  --surface-strong: #ffffff;
  --text: #1f1b24;
  --muted: #675f73;
  --primary: #6750a4;
  --primary-weak: #e9ddff;
  --border: rgba(31,27,36,.12);
  --shadow: 0 20px 60px rgba(17, 12, 24, .10);
}

[data-theme="dark"] {
  --bg: #0f0d14;
  --surface: rgba(27,24,34,.78);
  --surface-strong: #1b1822;
  --text: #f3edf7;
  --muted: #c5bdd1;
  --primary: #d0bcff;
  --primary-weak: #332d41;
  --border: rgba(243,237,247,.12);
  --shadow: 0 20px 60px rgba(0, 0, 0, .35);
}

* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: Inter, system-ui, sans-serif;
  background:
    radial-gradient(circle at top left, rgba(103,80,164,.18), transparent 30%),
    radial-gradient(circle at bottom right, rgba(208,188,255,.16), transparent 24%),
    var(--bg);
  color: var(--text);
}
a { color: inherit; text-decoration: none; }
.shell { min-height: 100vh; display: grid; grid-template-rows: auto 1fr; }
.topbar, .panel, .card {
  background: var(--surface);
  backdrop-filter: blur(18px);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}
.topbar {
  margin: 16px;
  border-radius: 24px;
  padding: 14px 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.brand { font-weight: 700; letter-spacing: .02em; }
.nav { display: flex; gap: 12px; }
.nav a, .btn, select, input, textarea { border-radius: 16px; }
.nav a, .btn { padding: 10px 14px; background: transparent; }
.nav a.active, .btn.primary { background: var(--primary); color: white; }
.layout { display: grid; grid-template-columns: 25% 25% 50%; gap: 16px; padding: 0 16px 16px; min-height: calc(100vh - 92px); }
.panel { border-radius: 24px; padding: 16px; overflow: auto; }
.stack { display: grid; gap: 12px; }
.item, .message, .mailbox { padding: 14px; border-radius: 18px; background: var(--surface-strong); border: 1px solid var(--border); }
.muted { color: var(--muted); }
.split { display: grid; gap: 12px; }
.toolbar { display:flex; gap:10px; align-items:center; flex-wrap: wrap; }
input, select, textarea { width: 100%; padding: 12px 14px; border: 1px solid var(--border); background: var(--surface-strong); color: var(--text); }
.messages { display:grid; gap:10px; }
.message.active { outline: 2px solid var(--primary); }
.grid-form { display:grid; gap:12px; }
@media (max-width: 1100px) { .layout { grid-template-columns: 1fr; } }