:root {
  --bg: #f6f7fb;
  --bg-tint: #eef1f9;
  --panel: #ffffff;
  --border: #e6e9f0;
  --border-strong: #d6dbe6;
  --text: #1b2130;
  --muted: #7a8296;
  --accent: #4f5ef0;
  --accent-hover: #4250dd;
  --accent-soft: #eef0fe;
  --accent-border: #d6dbfb;
  --success: #2f8555;
  --success-soft: #e9f6ee;
  --success-border: #c8e6d4;
  --danger: #cf3f4a;
  --danger-soft: #fdeff0;
  --danger-border: #f4ccd0;
  --shadow-sm: 0 1px 2px rgba(20, 27, 45, .04);
  --shadow-md: 0 4px 16px -6px rgba(20, 27, 45, .12), 0 1px 3px rgba(20, 27, 45, .04);
  --radius: 14px;
  --radius-sm: 10px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #12151d;
    --bg-tint: #171b26;
    --panel: #1a1f2b;
    --border: #272d3c;
    --border-strong: #333b4d;
    --text: #e6e9f2;
    --muted: #949cb2;
    --accent: #8b95ff;
    --accent-hover: #9aa3ff;
    --accent-soft: #232842;
    --accent-border: #343c66;
    --success: #6cc98e;
    --success-soft: #1c2a22;
    --success-border: #2c4536;
    --danger: #f0848d;
    --danger-soft: #2c1c20;
    --danger-border: #4a2a30;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, .3);
    --shadow-md: 0 4px 18px -6px rgba(0, 0, 0, .55), 0 1px 3px rgba(0, 0, 0, .3);
  }
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  padding: 0 20px 64px;
  min-height: 100vh;
  background:
    radial-gradient(1100px 420px at 50% -220px, var(--bg-tint), transparent 70%),
    var(--bg);
  color: var(--text);
  font-family: "Zen Kaku Gothic New", "Segoe UI", "Hiragino Kaku Gothic ProN", "Meiryo", system-ui, sans-serif;
  font-size: 15px;
  line-height: 1.7;
  letter-spacing: .01em;
  -webkit-font-smoothing: antialiased;
}

/* ---------- ヘッダー ---------- */

.site-header {
  max-width: 1000px;
  margin: 0 auto;
  padding: 40px 0 26px;
}
.brand { display: flex; align-items: center; gap: 14px; }
.brand-mark {
  flex: none;
  width: 42px;
  height: 42px;
  display: grid;
  place-items: center;
  border-radius: 12px;
  background: var(--accent);
  color: #fff;
  box-shadow: 0 6px 16px -6px var(--accent);
}
.brand-mark svg { width: 22px; height: 22px; }
.site-header h1 {
  margin: 0;
  font-size: 1.45rem;
  font-weight: 700;
  letter-spacing: .04em;
}
.subtitle {
  margin: 0;
  color: var(--muted);
  font-size: .82rem;
  letter-spacing: .03em;
}

main { max-width: 1000px; margin: 0 auto; }

/* ---------- ダッシュボード ---------- */

.dashboard {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
  margin-bottom: 22px;
}
.stat {
  position: relative;
  overflow: hidden;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 18px 14px;
  box-shadow: var(--shadow-sm);
}
.stat::before {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: 3px;
  background: var(--border-strong);
}
.stat-accent::before { background: var(--success); }
.stat-open::before { background: var(--accent); }
.stat-label {
  display: block;
  font-size: .76rem;
  font-weight: 500;
  color: var(--muted);
  letter-spacing: .08em;
}
.stat-value {
  font-size: 2.1rem;
  font-weight: 700;
  line-height: 1.15;
  font-variant-numeric: tabular-nums;
  letter-spacing: -.02em;
}
.stat-accent .stat-value { color: var(--success); }
.stat-open .stat-value { color: var(--accent); }
.stat-unit {
  font-size: .78rem;
  color: var(--muted);
  margin-left: 3px;
}

/* ---------- 最新の振り返り ---------- */

.latest {
  background: var(--panel);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  padding: 15px 20px 17px;
  margin-bottom: 22px;
  box-shadow: var(--shadow-sm);
}
.latest-head {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 5px;
}
.latest-label {
  font-size: .72rem;
  font-weight: 700;
  letter-spacing: .1em;
  color: var(--accent);
}
.latest-week {
  font-size: .74rem;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
}
.latest-text {
  margin: 0;
  white-space: pre-wrap;
  word-break: break-word;
  font-size: .92rem;
  line-height: 1.75;
}
.latest-empty { color: var(--muted); font-size: .85rem; }

/* ---------- エラー ---------- */

.error {
  display: flex;
  gap: 8px;
  background: var(--danger-soft);
  border: 1px solid var(--danger-border);
  color: var(--danger);
  border-radius: var(--radius-sm);
  padding: 11px 16px;
  margin: 0 0 18px;
  font-size: .86rem;
}
.error::before { content: "!"; font-weight: 700; }
.error[hidden] { display: none; } /* display 指定が hidden 属性を打ち消さないように */

/* ---------- パネル ---------- */

.columns {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
  align-items: start;
}

.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px 22px 26px;
  box-shadow: var(--shadow-md);
}
.panel-wide { margin-top: 18px; }

.panel-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px;
  margin: 30px 0 12px;
  padding-bottom: 9px;
  border-bottom: 1px solid var(--border);
}
.panel-head:first-child { margin-top: 0; }
.panel-head h2 {
  margin: 0;
  font-size: .9rem;
  font-weight: 700;
  letter-spacing: .06em;
}
.count {
  font-size: .76rem;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
}

/* ---------- フォーム ---------- */

.form { display: flex; flex-direction: column; gap: 10px; }
.form-inline { flex-direction: row; }
.form-inline input { flex: 1; min-width: 0; }

.field { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; }
.field label {
  font-size: .78rem;
  font-weight: 700;
  letter-spacing: .06em;
  color: var(--muted);
}
.field select { flex: 1; min-width: 220px; }

.form-foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}
.hint { font-size: .76rem; color: var(--muted); }

select {
  font: inherit;
  padding: 10px 13px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  background: var(--bg);
  color: inherit;
  cursor: pointer;
  transition: border-color .15s ease, box-shadow .15s ease;
}
select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

input[type="text"], textarea {
  font: inherit;
  width: 100%;
  padding: 10px 13px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  background: var(--bg);
  color: inherit;
  resize: vertical;
  transition: border-color .15s ease, box-shadow .15s ease, background .15s ease;
}
input[type="text"]::placeholder, textarea::placeholder { color: var(--muted); }
input[type="text"]:focus, textarea:focus {
  outline: none;
  background: var(--panel);
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

button {
  font: inherit;
  cursor: pointer;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  padding: 10px 18px;
  white-space: nowrap;
  transition: background .15s ease, color .15s ease, border-color .15s ease, transform .1s ease;
}
button:focus-visible {
  outline: none;
  box-shadow: 0 0 0 3px var(--accent-soft);
}
button:active { transform: translateY(1px); }

.btn-primary {
  background: var(--accent);
  color: #fff;
  font-weight: 700;
  letter-spacing: .04em;
  box-shadow: 0 6px 14px -8px var(--accent);
}
.btn-primary:hover { background: var(--accent-hover); }

/* ---------- 一覧 ---------- */

.list { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 10px; }

.item {
  display: flex;
  align-items: flex-start;
  gap: 11px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 13px 14px;
  background: var(--panel);
  transition: border-color .15s ease, box-shadow .15s ease;
}
.item:hover { border-color: var(--border-strong); box-shadow: var(--shadow-sm); }

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

.item-title {
  font-weight: 700;
  word-break: break-word;
  line-height: 1.5;
}
.item-body {
  margin: 5px 0 0;
  white-space: pre-wrap;
  word-break: break-word;
  font-size: .9rem;
  color: var(--text);
  opacity: .82;
}
.item-meta {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 8px;
  font-size: .74rem;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
  letter-spacing: .02em;
}

/* チェックボックス */
.item input[type="checkbox"] {
  flex: none;
  appearance: none;
  -webkit-appearance: none;
  margin: 4px 0 0;
  width: 19px;
  height: 19px;
  border: 1.5px solid var(--border-strong);
  border-radius: 6px;
  background: var(--bg);
  cursor: pointer;
  display: grid;
  place-items: center;
  transition: background .15s ease, border-color .15s ease;
}
.item input[type="checkbox"]:hover { border-color: var(--accent); }
.item input[type="checkbox"]:checked {
  background: var(--success);
  border-color: var(--success);
}
.item input[type="checkbox"]:checked::after {
  content: "";
  width: 5px;
  height: 9px;
  margin-top: -2px;
  border: solid #fff;
  border-width: 0 2px 2px 0;
  transform: rotate(45deg);
}
.item input[type="checkbox"]:focus-visible {
  outline: none;
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.task-done .item-title { text-decoration: line-through; color: var(--muted); }

/* バッジ */
.badge {
  display: inline-block;
  font-size: .68rem;
  font-weight: 700;
  letter-spacing: .06em;
  padding: 1px 9px;
  border-radius: 999px;
  border: 1px solid transparent;
}
.badge-open { background: var(--accent-soft); color: var(--accent); border-color: var(--accent-border); }
.badge-done { background: var(--success-soft); color: var(--success); border-color: var(--success-border); }
.badge-week { background: var(--bg); color: var(--muted); border-color: var(--border-strong); }

/* 編集ボタン */
.btn-quiet {
  flex: none;
  background: none;
  color: var(--muted);
  font-size: .75rem;
  padding: 4px 10px;
  border-color: var(--border);
  opacity: .75;
}
.btn-quiet:hover {
  opacity: 1;
  color: var(--accent);
  background: var(--accent-soft);
  border-color: var(--accent-border);
}

/* 削除ボタン */
.btn-delete {
  flex: none;
  background: none;
  color: var(--muted);
  font-size: .75rem;
  padding: 4px 10px;
  border-color: var(--border);
  opacity: .75;
}
.btn-delete:hover {
  opacity: 1;
  color: var(--danger);
  background: var(--danger-soft);
  border-color: var(--danger-border);
}

.empty {
  color: var(--muted);
  font-size: .85rem;
  text-align: center;
  padding: 26px 10px;
  border: 1px dashed var(--border-strong);
  border-radius: var(--radius-sm);
}

/* ---------- レスポンシブ ---------- */

@media (max-width: 860px) {
  .columns { grid-template-columns: 1fr; }
  .dashboard { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 560px) {
  body { padding: 0 16px 48px; }
  .site-header { padding: 28px 0 20px; }
  .dashboard { grid-template-columns: 1fr; gap: 10px; }
  .stat { padding: 12px 16px; }
  .stat-value { font-size: 1.7rem; }
  .panel { padding: 18px 16px 22px; }
}