:root {
  --bg: #f4f6fb;
  --panel: #ffffff;
  --border: #e2e6ef;
  --text: #1f2733;
  --muted: #7a8699;
  --accent: #4361ee;
  --accent-dark: #3049c9;
  --danger: #e5484d;
  --done: #12b886;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.06), 0 4px 12px rgba(0, 0, 0, 0.04);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  padding: 24px 16px 64px;
}

.app-header {
  max-width: 960px;
  margin: 0 auto 24px;
  text-align: center;
}
.app-header h1 { margin: 0; font-size: 28px; }
.subtitle { margin: 4px 0 0; color: var(--muted); font-size: 14px; }

/* ダッシュボード */
.dashboard {
  max-width: 960px;
  margin: 0 auto 28px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}
.stat-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 20px;
  text-align: center;
  box-shadow: var(--shadow);
}
.stat-card.highlight { border-color: var(--accent); }
.stat-num { font-size: 34px; font-weight: 700; color: var(--accent); }
.stat-label { font-size: 13px; color: var(--muted); margin-top: 4px; }

/* 2カラム */
.columns {
  max-width: 960px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}
.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 20px;
  box-shadow: var(--shadow);
}
.panel h2 { margin: 0 0 14px; font-size: 18px; }

/* 追加フォーム */
.add-form { display: flex; flex-direction: column; gap: 8px; margin-bottom: 18px; }
.add-form input,
.add-form textarea {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 14px;
  font-family: inherit;
  resize: vertical;
}
.add-form input:focus,
.add-form textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.12);
}
.add-form button {
  align-self: flex-end;
  background: var(--accent);
  color: #fff;
  border: none;
  padding: 9px 18px;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s;
}
.add-form button:hover { background: var(--accent-dark); }

/* 一覧 */
.list { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 10px; }
.list:empty::after {
  content: "まだありません";
  color: var(--muted);
  font-size: 13px;
}

.item {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px 14px;
  background: #fbfcfe;
}
.item-title { font-weight: 600; word-break: break-word; }
.item-body { font-size: 14px; color: #45505f; white-space: pre-wrap; word-break: break-word; margin-top: 4px; }
.item-meta { font-size: 12px; color: var(--muted); margin-top: 8px; display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }

.item-actions { margin-top: 10px; display: flex; gap: 8px; }
.btn-sm {
  border: none;
  border-radius: 6px;
  padding: 5px 12px;
  font-size: 12px;
  cursor: pointer;
  font-weight: 600;
}
.btn-done { background: var(--done); color: #fff; }
.btn-undo { background: #e9ecf3; color: var(--text); }
.btn-del { background: #fdecec; color: var(--danger); }
.btn-del:hover { background: var(--danger); color: #fff; }

/* タスクの完了状態 */
.task.done .item-title { text-decoration: line-through; color: var(--muted); }
.badge {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 999px;
  font-size: 11px;
  font-weight: 600;
}
.badge-done { background: #e3f9ef; color: var(--done); }
.badge-todo { background: #fff3e0; color: #d97706; }

/* スマホ対応 */
@media (max-width: 720px) {
  .columns { grid-template-columns: 1fr; }
  .dashboard { grid-template-columns: 1fr; }
}