/* ===========================
   Daily To-Do - スタイル
   =========================== */

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

:root {
  color-scheme: light;

  --color-bg-1: #f4f6fb;
  --color-bg-2: #eceef8;
  --color-surface: #fff;
  --color-text: #2a2d3a;
  --color-muted: #666a78;
  --color-label: #8a8d99;
  --color-faint: #aaadb8;
  --color-border: #dcdfe8;
  --color-divider: #eef0f6;
  --color-primary: #4f6df5;
  --color-primary-2: #8b5cf6;
  --color-primary-hover: #3e58d6;
  --color-primary-tint: #eef1ff;

  --priority-high: #ef4444;
  --priority-high-tint: #fef2f2;
  --priority-medium: #f59e0b;
  --priority-medium-tint: #fffbeb;
  --priority-low: #10b981;
  --priority-low-tint: #ecfdf5;

  --shadow-soft: 0 2px 10px rgba(30, 34, 60, 0.07);
  --shadow-lift: 0 8px 20px rgba(30, 34, 60, 0.12);
}

:root[data-theme="dark"] {
  /* ブラウザ標準の日付ピッカーのアイコン・カレンダーもダーク配色にする */
  color-scheme: dark;

  --color-bg-1: #14161d;
  --color-bg-2: #1b1e28;
  --color-surface: #22252f;
  --color-text: #e8e9f0;
  --color-muted: #b0b3c0;
  --color-label: #92959f;
  --color-faint: #6b6e79;
  --color-border: #383c48;
  --color-divider: #2e313d;
  --color-primary: #7c93ff;
  --color-primary-2: #a78bfa;
  --color-primary-hover: #93a6ff;
  --color-primary-tint: #232a4a;

  --priority-high: #f87171;
  --priority-high-tint: #3a2222;
  --priority-medium: #fbbf24;
  --priority-medium-tint: #3a2f14;
  --priority-low: #34d399;
  --priority-low-tint: #12312a;

  --shadow-soft: 0 2px 10px rgba(0, 0, 0, 0.3);
  --shadow-lift: 0 10px 24px rgba(0, 0, 0, 0.4);
}

html {
  overflow-x: hidden;
}

body {
  font-family: -apple-system, "Segoe UI", "Hiragino Sans", system-ui, sans-serif;
  margin: 0;
  padding: 40px 20px 64px;
  background: linear-gradient(160deg, var(--color-bg-1) 0%, var(--color-bg-2) 100%);
  background-attachment: fixed;
  color: var(--color-text);
  overflow-x: hidden;
  transition: background 0.2s ease, color 0.2s ease;
}

header, main {
  max-width: 680px;
  margin: 0 auto;
}

header {
  margin-bottom: 36px;
}

.header-row {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: flex-start;
  gap: 16px;
}

.header-row > div {
  min-width: 0;
}

header h1 {
  font-size: 30px;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 4px;
  background: linear-gradient(100deg, var(--color-primary), var(--color-primary-2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

header p {
  color: var(--color-muted);
  margin: 0;
  font-size: 14px;
}

.theme-toggle {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  width: 44px;
  height: 44px;
  font-size: 19px;
  cursor: pointer;
  box-shadow: var(--shadow-soft);
  flex-shrink: 0;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.theme-toggle:hover {
  transform: translateY(-2px) rotate(-8deg);
  box-shadow: var(--shadow-lift);
}

h2 {
  font-size: 19px;
  font-weight: 700;
  margin: 0 0 16px;
  padding-left: 12px;
  border-left: 4px solid var(--color-primary);
}

/* フォームセクション */
#add-task-section {
  background: var(--color-surface);
  border-radius: 16px;
  padding: 26px;
  margin-bottom: 40px;
  box-shadow: var(--shadow-soft);
  border: 1px solid var(--color-divider);
}

.form-group {
  margin-bottom: 20px;
}

.form-row {
  display: flex;
  gap: 16px;
}

.form-row .form-group {
  flex: 1;
  min-width: 0;
}

.form-group label {
  display: block;
  font-weight: 700;
  font-size: 14px;
  margin-bottom: 2px;
}

.form-group small {
  display: block;
  color: var(--color-label);
  font-size: 13px;
  margin-bottom: 6px;
}

.form-group input[type="text"],
.form-group input[type="date"],
.form-group select {
  width: 100%;
  padding: 11px 14px;
  font-size: 16px;
  border: 1px solid var(--color-border);
  border-radius: 10px;
  box-sizing: border-box;
  background: var(--color-surface);
  color: var(--color-text);
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.form-group input:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-tint);
}

.checkbox-group {
  margin-bottom: 24px;
}

.checkbox-label {
  display: flex !important;
  align-items: center;
  gap: 8px;
  font-weight: normal !important;
  cursor: pointer;
}

.checkbox-label input {
  width: 18px;
  height: 18px;
  accent-color: var(--color-primary);
}

button[type="submit"] {
  background: linear-gradient(100deg, var(--color-primary), var(--color-primary-2));
  color: #fff;
  border: none;
  padding: 13px 26px;
  font-size: 15px;
  font-weight: 600;
  border-radius: 10px;
  cursor: pointer;
  box-shadow: 0 4px 14px rgba(79, 109, 245, 0.35);
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

button[type="submit"]:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(79, 109, 245, 0.4);
}

button[type="submit"]:active {
  transform: translateY(0);
}

.secondary-btn {
  background: var(--color-surface);
  color: var(--color-primary);
  border: 1px solid var(--color-primary);
  padding: 8px 18px;
  font-size: 13px;
  font-weight: 600;
  border-radius: 999px;
  cursor: pointer;
  white-space: nowrap;
  transition: background 0.15s ease, transform 0.15s ease;
}

.secondary-btn:hover {
  background-color: var(--color-primary-tint);
  transform: translateY(-1px);
}

.secondary-btn.active {
  background: linear-gradient(100deg, var(--color-primary), var(--color-primary-2));
  color: #fff;
  border-color: transparent;
}

/* セクション見出し行 */
.section-header {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  margin-bottom: 16px;
  gap: 12px;
}

.section-header h2 {
  margin-bottom: 0;
}

#tasks-section, #completed-section {
  margin-bottom: 40px;
}

/* ===========================
   バックアップ（エクスポート／インポート）
   =========================== */

#backup-section {
  margin-bottom: 40px;
}

.backup-note {
  color: var(--color-muted);
  font-size: 13px;
  line-height: 1.5;
  margin: 0 0 12px;
}

.backup-buttons {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.empty-message {
  color: var(--color-label);
  font-size: 14px;
  text-align: center;
  padding: 32px 20px;
  background: var(--color-surface);
  border: 1px dashed var(--color-border);
  border-radius: 16px;
}

/* ===========================
   タスクカード
   =========================== */

.task-card {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  background: var(--color-surface);
  border-radius: 14px;
  padding: 16px 20px;
  margin-bottom: 12px;
  box-shadow: var(--shadow-soft);
  border-left: 4px solid transparent;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.task-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lift);
}

.task-card.priority-high { border-left-color: var(--priority-high); }
.task-card.priority-medium { border-left-color: var(--priority-medium); }
.task-card.priority-low { border-left-color: var(--priority-low); }

.task-card.due-warning {
  outline: 2px solid var(--priority-high);
  outline-offset: -2px;
}

.task-card.completed {
  opacity: 0.65;
}

.task-checkbox {
  appearance: none;
  -webkit-appearance: none;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  border: 2px solid var(--color-border);
  cursor: pointer;
  flex-shrink: 0;
  margin-top: 2px;
  position: relative;
  background: var(--color-surface);
  transition: transform 0.15s ease, background 0.15s ease, border-color 0.15s ease;
}

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

.task-checkbox:checked {
  background: linear-gradient(100deg, var(--color-primary), var(--color-primary-2));
  border-color: transparent;
  transform: scale(1.08);
}

.task-checkbox:checked::after {
  content: '✓';
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 14px;
  font-weight: bold;
}

.task-body {
  flex: 1;
  min-width: 0;
}

.task-text {
  margin: 0 0 8px;
  word-break: break-word;
  font-size: 15px;
}

.task-card.completed .task-text {
  text-decoration: line-through;
  color: var(--color-faint);
}

.task-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 12px;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: 999px;
}

.badge-priority-high { background: var(--priority-high-tint); color: var(--priority-high); }
.badge-priority-medium { background: var(--priority-medium-tint); color: var(--priority-medium); }
.badge-priority-low { background: var(--priority-low-tint); color: var(--priority-low); }

.badge-priority-high::before,
.badge-priority-medium::before,
.badge-priority-low::before {
  content: '●';
  font-size: 8px;
}

.badge-due {
  background: var(--color-divider);
  color: var(--color-muted);
}

.badge-due-warning {
  background: var(--priority-high-tint);
  color: var(--priority-high);
}

.badge-streak {
  background: linear-gradient(100deg, var(--color-primary-tint), var(--priority-medium-tint));
  color: var(--color-primary);
}

.task-delete-btn {
  background: none;
  border: none;
  color: var(--color-faint);
  font-size: 16px;
  cursor: pointer;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  flex-shrink: 0;
  line-height: 1;
  transition: background 0.15s ease, color 0.15s ease;
}

.task-delete-btn:hover {
  color: var(--priority-high);
  background: var(--priority-high-tint);
}

@media (max-width: 480px) {
  .form-row {
    flex-direction: column;
    gap: 20px;
  }

  .header-row,
  .section-header {
    display: block;
  }

  .theme-toggle {
    margin-top: 12px;
  }

  .secondary-btn {
    display: inline-block;
    margin-top: 10px;
  }
}