/* Grayish palette and clean layout */
:root {
  --bg: #f3f4f6;          /* gray-100 */
  --bg-soft: #e5e7eb;      /* gray-200 */
  --text: #1f2937;         /* gray-800 */
  --muted: #4b5563;        /* gray-600 */
  --card: #ffffff;         /* white */
  --border: #d1d5db;       /* gray-300 */
  --primary: #6b7280;      /* gray-500 */
  --primary-hover: #4b5563;/* gray-600 */
  --disabled: #9ca3af;     /* gray-400 */
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: 'Poppins', system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
  color: var(--text);
  background: linear-gradient(180deg, var(--bg), var(--bg-soft));
  display: flex;
  min-height: 100vh;
  flex-direction: column;
}

.site-header { text-align: center; padding: 32px 16px 16px; }
.site-header h1 { margin: 0; font-size: 28px; font-weight: 600; letter-spacing: 0.3px; }
.subtitle { margin: 8px 0 0; color: var(--muted); font-size: 14px; }

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
  padding: 16px;
  width: 100%;
  max-width: 900px;
  margin: 0 auto;
}

.card {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: flex-start;
  gap: 6px;
  padding: 20px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--card);
  text-decoration: none;
  color: var(--text);
  box-shadow: 0 2px 6px rgba(17,24,39,0.06);
  transition: transform 0.12s ease, box-shadow 0.12s ease, background 0.12s ease;
}
.card:hover { transform: translateY(-2px); box-shadow: 0 6px 14px rgba(17,24,39,0.10); }
.card:active { transform: translateY(0); }

.card-title { font-weight: 600; font-size: 16px; }
.card-desc { color: var(--muted); font-size: 13px; }

.btn-primary { border-color: var(--primary); }
.btn-primary:hover { background: #f9fafb; }

.btn-disabled { cursor: not-allowed; opacity: 0.7; }

/* Attendance page */
.page { width: 100%; max-width: 900px; margin: 0 auto; padding: 24px 16px; }
.back { display: inline-block; margin-bottom: 8px; color: var(--muted); text-decoration: none; }
.back:hover { color: var(--text); }

.page h1 { margin: 8px 0 16px; font-size: 24px; font-weight: 600; }
.help { margin-top: -8px; color: var(--muted); font-size: 14px; }

.form {
  margin-top: 16px; padding: 16px; border: 1px solid var(--border);
  border-radius: 12px; background: var(--card); box-shadow: 0 2px 6px rgba(17,24,39,0.06);
}
.row { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-bottom: 12px; }
.label { font-size: 13px; color: var(--muted); margin-bottom: 6px; display: block; }

select, input[type="number"], button.calculate {
  width: 100%; padding: 10px 12px; border-radius: 10px; border: 1px solid var(--border);
  background: #fafafa; color: var(--text); font-size: 14px;
}
select:focus, input[type="number"]:focus, button.calculate:focus { outline: 2px solid var(--primary); outline-offset: 2px; }

button.calculate { background: var(--primary); color: white; border-color: var(--primary); cursor: pointer; }
button.calculate:hover { background: var(--primary-hover); }

.result { margin-top: 14px; padding: 12px; border-radius: 10px; background: #f9fafb; border: 1px solid var(--border); }
.result p { margin: 0; }
.result .ok { color: #065f46; }
.result .warn { color: #92400e; }
.result .err { color: #7f1d1d; }

.site-footer {
  margin-top: auto; text-align: center; padding: 16px; border-top: 1px solid var(--border);
}
.signature {
  font-family: 'Pacifico', cursive; font-size: 15px; color: var(--muted);
}