*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --bg: #fdf6f0;
  --surface: #ffffff;
  --border: #e8ddd5;
  --text: #2c1810;
  --text-muted: #9c8880;
  --accent: #c0392b;
  --accent-hover: #a93226;
  --selected-bg: #c0392b;
  --selected-text: #ffffff;
  --today-ring: #e67e22;
  --past: #d9cec9;
  --radius: 10px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  padding: 2rem 1rem 4rem;
  scrollbar-gutter: stable;
}

/* ── Header ─────────────────────────────────────── */
header {
  text-align: center;
  margin-bottom: 2.5rem;
}

header h1 {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.5px;
}

header .subtitle {
  margin-top: 0.5rem;
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* ── Toast ───────────────────────────────────────── */
.toast {
  position: fixed;
  top: 1.25rem;
  left: 50%;
  transform: translateX(-50%);
  background: #27ae60;
  color: #fff;
  padding: 0.65rem 1.4rem;
  border-radius: 99px;
  font-size: 0.9rem;
  font-weight: 500;
  box-shadow: 0 4px 16px rgba(0,0,0,0.15);
  z-index: 100;
  transition: opacity 0.5s, transform 0.5s;
}

.toast--hide {
  opacity: 0;
  transform: translateX(-50%) translateY(-8px);
}

/* ── Month grid ──────────────────────────────────── */
.months-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
  max-width: 1020px;
  margin: 0 auto;
}

.month-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1rem 1rem;
  align-self: start;
  container-type: inline-size;
}

.month-card h2 {
  font-size: 1rem;
  font-weight: 600;
  text-align: center;
  margin-bottom: 1rem;
  letter-spacing: 0.3px;
}

/* ── Calendar grid ───────────────────────────────── */
.calendar-grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  /* row height = column width = (card - h-padding - 6 gaps) / 7 */
  grid-auto-rows: calc((100cqi - 2rem - 18px) / 7);
  gap: 3px;
}

.wd-header {
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--text-muted);
  text-align: center;
  text-transform: uppercase;
  letter-spacing: 0.4px;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* ── Day cells ───────────────────────────────────── */
.day {
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 6px;
  font-size: 0.85rem;
  user-select: none;
}

.day--empty {
  background: transparent;
}

.day--past {
  color: var(--past);
  cursor: default;
}

/* clickable label wrapping checkbox */
label.day {
  cursor: pointer;
  position: relative;
  transition: background 0.12s, color 0.12s;
}

label.day input[type="checkbox"] {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
  pointer-events: none;
}

label.day:hover {
  background: #fae5e2;
}

label.day:has(input:checked) {
  background: var(--selected-bg);
  color: var(--selected-text);
  font-weight: 600;
}

label.day:has(input:checked):hover {
  background: var(--accent-hover);
}

/* today ring */
label.day.day--today .day-num {
  position: relative;
}

label.day.day--today:not(:has(input:checked)) {
  box-shadow: inset 0 0 0 2px var(--today-ring);
}

/* ── Actions ─────────────────────────────────────── */
.actions {
  margin-top: 2rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
}

button[type="submit"] {
  background: var(--accent);
  color: #fff;
  border: none;
  padding: 0.75rem 2rem;
  border-radius: 99px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s, transform 0.1s;
}

button[type="submit"]:hover {
  background: var(--accent-hover);
}

button[type="submit"]:active {
  transform: scale(0.97);
}

.selection-count {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* ── Preference card ─────────────────────────────── */
.pref-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem 1.5rem;
  max-width: 1020px;
  margin: 1.5rem auto 0;
}

.pref-card h2 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.pref-subtitle {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}

/* ── Slider ──────────────────────────────────────── */
.slider-wrap {
  padding: 0 0.25rem;
}

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  display: block;
  width: 100%;
  height: 6px;
  border-radius: 3px;
  outline: none;
  cursor: pointer;
  background: linear-gradient(
    to right,
    var(--accent) var(--fill, 50%),
    var(--border) var(--fill, 50%)
  );
}

/* Firefox track — transparent so element background shows through */
input[type="range"]::-moz-range-track {
  background: transparent;
  height: 6px;
  border-radius: 3px;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: #fff;
  border: 2px solid var(--accent);
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.15);
  cursor: pointer;
  transition: box-shadow 0.15s;
}

input[type="range"]:hover::-webkit-slider-thumb,
input[type="range"]:focus::-webkit-slider-thumb {
  box-shadow: 0 0 0 5px rgba(192, 57, 43, 0.12);
}

input[type="range"]::-moz-range-thumb {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: #fff;
  border: 2px solid var(--accent);
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.15);
  cursor: pointer;
}

.slider-labels {
  display: flex;
  justify-content: space-between;
  margin-top: 0.75rem;
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-muted);
}