:root {
  color-scheme: light dark;
  --border: #d0d5dd;
  --muted: #667085;
  --danger-bg: #fee4e2;
  --danger-fg: #912018;
  --success-bg: #d1fadf;
  --success-fg: #05603a;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  color: #1d2939;
  background: #f9fafb;
}

h1 { font-size: 1.4rem; margin: 0; }
h2 { font-size: 1.1rem; }

.auth-page {
  max-width: 380px;
  margin: 10vh auto 0;
  padding: 2rem;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 8px;
}

.auth-page form {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  margin-top: 1rem;
}

.auth-page label { font-size: 0.85rem; color: var(--muted); margin-top: 0.5rem; }

.auth-page input {
  padding: 0.5rem;
  border: 1px solid var(--border);
  border-radius: 4px;
  font-size: 1rem;
}

.auth-page button,
.admin-page button {
  margin-top: 1rem;
  padding: 0.6rem;
  border: none;
  border-radius: 4px;
  background: #1570ef;
  color: #fff;
  font-size: 1rem;
  cursor: pointer;
}

.admin-page button { margin-top: 0; padding: 0.35rem 0.6rem; font-size: 0.85rem; }

.alert {
  padding: 0.6rem 0.8rem;
  border-radius: 4px;
  margin: 0;
  list-style: none;
}

.alert-error { background: var(--danger-bg); color: var(--danger-fg); }
.alert-success { background: var(--success-bg); color: var(--success-fg); }

.portal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
  background: #fff;
  border-bottom: 1px solid var(--border);
}

.portal-user { display: flex; gap: 1rem; align-items: center; font-size: 0.9rem; }
.portal-user a { color: #1570ef; text-decoration: none; }

.dashboard, .admin-page { padding: 2rem; }

.sheet-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1rem;
}

.sheet-card {
  display: block;
  padding: 1.2rem;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 8px;
  text-decoration: none;
  color: inherit;
}

.sheet-card:hover { border-color: #1570ef; }

.admin-page section { margin-bottom: 2rem; }

table {
  width: 100%;
  border-collapse: collapse;
  background: #fff;
}

th, td {
  text-align: left;
  padding: 0.5rem 0.75rem;
  border-bottom: 1px solid var(--border);
  font-size: 0.9rem;
}

td.actions form { display: flex; gap: 0.4rem; align-items: center; }

@media (prefers-color-scheme: dark) {
  body { background: #101828; color: #f2f4f7; }
  .auth-page, .portal-header, .sheet-card, table { background: #1d2939; border-color: #344054; }
  th, td { border-color: #344054; }
  .auth-page label { color: #98a2b3; }
}