/* Design OS Lab — sign-in page. Standalone (not app.css) because the gate is
   served before any session exists; it shares app.css's palette by hand. */
:root {
  --ivory: #F7F5F0;
  --paper: #FDFCF9;
  --ink: #1E1B16;
  --ink-dim: rgba(30, 27, 22, 0.58);
  --line: rgba(30, 27, 22, 0.10);
  --line-strong: rgba(30, 27, 22, 0.18);
  --accent: #8A6D3B;
  --red: #8C3B2E;
  --shadow: 0 1px 2px rgba(30,27,22,.05), 0 8px 28px rgba(30,27,22,.07);
  --r: 10px;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body {
  background: var(--ivory);
  color: var(--ink);
  font: 15px/1.5 -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px;
}
.gate { width: 100%; max-width: 340px; }
.brand { text-align: center; margin-bottom: 28px; }
.brand-mark { font-size: 22px; font-weight: 600; letter-spacing: -0.01em; }
.brand-sub {
  font-size: 10px; letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--ink-dim); margin-top: 6px;
}
form {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--r);
  box-shadow: var(--shadow);
  padding: 24px;
}
label {
  display: block; font-size: 12px; font-weight: 600;
  margin-bottom: 8px; color: var(--ink);
}
input {
  width: 100%; padding: 10px 12px; font: inherit;
  background: var(--ivory);
  border: 1px solid var(--line-strong);
  border-radius: 8px; color: var(--ink);
}
input:focus { outline: 2px solid var(--accent); outline-offset: 1px; }
button {
  width: 100%; margin-top: 14px; padding: 10px 12px;
  font: inherit; font-weight: 600;
  background: var(--ink); color: var(--paper);
  border: 0; border-radius: 8px; cursor: pointer;
}
button:disabled { opacity: 0.6; cursor: default; }
.err { margin-top: 12px; font-size: 13px; color: var(--red); }
.hidden { display: none; }