:root {
  --bg: #f4f7fb;
  --card: #ffffff;
  --text: #172031;
  --muted: #61708a;
  --primary: #3966ff;
  --primary-hover: #2b4fd1;
  --border: #dde4f0;
  --success: #14945c;
  --danger-bg: #f4dce2;
  --danger-text: #7e1334;
  --subtle-btn-bg: #e9eef9;
  --subtle-btn-text: #2a3f6d;
  --selected-bg: #eef2ff;
}

html[data-theme="dark"] {
  --bg: #0e1118;
  --card: #171c28;
  --text: #eef3ff;
  --muted: #a5b1ca;
  --primary: #7d9bff;
  --primary-hover: #6285ff;
  --border: #2b3345;
  --success: #3cb581;
  --danger-bg: #472633;
  --danger-text: #ffcedc;
  --subtle-btn-bg: #242d40;
  --subtle-btn-text: #d6e1ff;
  --selected-bg: #26314b;
}

* { box-sizing: border-box; }

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

.app {
  max-width: 920px;
  margin: 0 auto;
  padding: 28px 16px 48px;
}

.app__header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
}

.app__header h1 { margin: 0; }
.app__header p { margin-top: 8px; color: var(--muted); }

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 18px;
  margin-top: 16px;
}

.list-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.month-controls { display: inline-flex; align-items: center; gap: 8px; }
.helper-text { margin: 8px 0 0; color: var(--muted); font-size: 0.9rem; }
.calendar { margin-top: 10px; }

.calendar-weekdays,
.calendar-grid {
  display: grid;
  grid-template-columns: repeat(7, minmax(0, 1fr));
  gap: 6px;
}

.calendar-weekdays { margin-bottom: 6px; }

.calendar-weekday,
.calendar-day {
  border-radius: 10px;
  text-align: center;
  padding: 8px 6px;
}

.calendar-weekday { color: var(--muted); font-size: 0.84rem; }

.calendar-day {
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--text);
  cursor: pointer;
  min-height: 66px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.calendar-day.outside { opacity: 0.45; }
.calendar-day.selected { border-color: var(--primary); background: var(--selected-bg); }
.calendar-day .count { font-size: 0.75rem; color: var(--primary); }

.task-form { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.task-form label { display: flex; flex-direction: column; gap: 6px; font-size: 0.9rem; }

.task-form label:nth-child(1),
.task-form label:nth-child(7),
.task-form button { grid-column: 1 / -1; }

input, textarea, button, select { font: inherit; }

input, textarea, select {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px 12px;
  background: var(--card);
  color: var(--text);
}

button {
  border: none;
  background: var(--primary);
  color: #fff;
  padding: 11px 14px;
  border-radius: 10px;
  cursor: pointer;
}

button:hover { background: var(--primary-hover); }

.secondary {
  background: var(--subtle-btn-bg);
  color: var(--subtle-btn-text);
}

.task-list {
  list-style: none;
  padding: 0;
  margin: 12px 0 0;
  display: grid;
  gap: 10px;
}

.task-item {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px;
  display: flex;
  justify-content: space-between;
  gap: 12px;
  background: var(--card);
}

.task-item.completed {
  border-color: #2f855f;
  background: rgba(47, 133, 95, 0.15);
}

.task-title { margin: 0; font-size: 1rem; }
.task-meta { margin: 5px 0; color: var(--muted); font-size: 0.9rem; }
.task-note { margin: 0; color: var(--text); white-space: pre-wrap; }

.task-actions { display: flex; flex-direction: column; gap: 6px; min-width: 84px; }
.task-actions button { padding: 8px 10px; font-size: 0.85rem; }
.done { background: var(--success); }
.delete { background: var(--danger-bg); color: var(--danger-text); }
.selected-date-label, .empty-state { margin-top: 12px; color: var(--muted); }

@media (max-width: 640px) {
  .task-form { grid-template-columns: 1fr; }
  .task-item { flex-direction: column; }
  .task-actions { flex-direction: row; }
  .app__header { flex-direction: column; align-items: stretch; }
}