:root {
  color-scheme: light;
  --page: #f6f6f3;
  --card: #fff;
  --ink: #0b0b0b;
  --muted: #52514e;
  --border: #e9e8e2;
  --accent: #2a78d6;
}
@media (prefers-color-scheme: dark) {
  :root {
    color-scheme: dark;
    --page: #0d0d0d;
    --card: #1a1a19;
    --ink: #fff;
    --muted: #c3c2b7;
    --border: #383835;
    --accent: #3987e5;
  }
}
* { box-sizing: border-box; }
body { margin: 0; padding: 24px; background: var(--page); color: var(--ink); font: 16px/1.5 system-ui, sans-serif; }
.session-card { max-width: 440px; margin: 10vh auto; padding: 28px; border: 1px solid var(--border); border-radius: 16px; background: var(--card); }
.session-card.wide { max-width: 680px; }
h1 { margin: 0 0 12px; }
p { color: var(--muted); }
label { display: block; margin: 14px 0; }
input { display: block; width: 100%; padding: 10px; margin-top: 5px; border: 1px solid var(--border); border-radius: 8px; background: var(--page); color: var(--ink); font: inherit; }
button { padding: 10px 18px; border: 0; border-radius: 8px; background: var(--accent); color: #fff; font: inherit; cursor: pointer; }
button:disabled { opacity: .6; cursor: wait; }
a { color: var(--accent); }
li { margin-bottom: 10px; }
[hidden] { display: none; }