:root {
  --bg: #f7f9fc;
  --card: #ffffff;
  --primary: #cf3c8c;
  --primary-light: #f7e3ef;
  --text: #1f2937;
  --muted: #6b7280;
  --border: #e5e7eb;
  --success: #059669;
  --error: #dc2626;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
}

.app-header {
  padding: 2rem 1.5rem 1rem;
  text-align: center;
}

.app-header h1 {
  margin: 0 0 0.25rem;
}

.subtitle {
  margin: 0;
  color: var(--muted);
}

.app {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 1.5rem 2rem;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

.controls {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1rem;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.04);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.nav button {
  background: none;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.5rem 0.75rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

.nav button:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.month-label {
  font-size: 1.25rem;
  font-weight: 600;
  text-align: center;
}

.month-key {
  text-align: center;
  color: var(--muted);
  font-size: 0.9rem;
}

.selection-display {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 0.5rem;
  margin-top: 1rem;
  color: var(--text);
}

.actions {
  margin-top: 0.75rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

button.primary {
  background: var(--primary);
  color: white;
  border: none;
  padding: 0.6rem 1.2rem;
  border-radius: 8px;
  cursor: pointer;
  transition: transform 0.1s ease, box-shadow 0.2s ease;
}

button.primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 10px 20px rgba(207, 60, 140, 0.2);
}

button.secondary {
  background: var(--primary-light);
  color: var(--primary);
  border: 1px solid var(--primary);
  padding: 0.55rem 1rem;
  border-radius: 8px;
  cursor: pointer;
}

button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.status {
  color: var(--success);
  font-size: 0.95rem;
}

.error {
  margin-top: 0.75rem;
  padding: 0.75rem;
  border-radius: 8px;
  background: #fef2f2;
  color: var(--error);
  border: 1px solid #fecdd3;
}

.calendar {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1rem;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.04);
}

.weekdays, .days {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  text-align: center;
  gap: 0.25rem;
}

.weekdays span {
  color: var(--muted);
  font-size: 0.9rem;
  padding-bottom: 0.25rem;
}

.day {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.75rem 0.25rem;
  min-height: 70px;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  position: relative;
  cursor: pointer;
  background: white;
  transition: all 0.2s ease;
}

.day:hover {
  border-color: var(--primary);
}

.day.disabled {
  color: var(--muted);
  background: #f3f4f6;
  cursor: default;
}

.day .date-number {
  font-weight: 600;
}

.day.selected {
  border-color: var(--primary);
  background: var(--primary-light);
}

.day.in-range {
  background: #fde8f3;
}

.day.start::after, .day.end::after {
  content: '';
  position: absolute;
  top: 6px;
  right: 6px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--primary);
}

@media (min-width: 900px) {
  .app {
    grid-template-columns: 360px 1fr;
  }
}