:root {
  --bg: #f6f7f9;
  --card: #ffffff;
  --text: #1f2933;
  --muted: #6b7280;
  --accent: #2563eb;
  --border: #e5e7eb;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Hiragino Kaku Gothic ProN", "Noto Sans JP", "Yu Gothic", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
}

header {
  background: var(--card);
  border-bottom: 1px solid var(--border);
}

.container {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 16px;
}

header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 12px;
  padding-bottom: 12px;
}

.site-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
}

main {
  padding: 24px 0 48px;
}

h1 {
  font-size: 1.5rem;
  margin: 0 0 8px;
}

.lead {
  color: var(--muted);
  margin: 0 0 24px;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px;
  margin-bottom: 20px;
}

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

.tool-list a {
  display: block;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px 20px;
  text-decoration: none;
  color: var(--text);
}

.tool-list a:hover {
  border-color: var(--accent);
}

.tool-list .name {
  font-weight: 700;
  color: var(--accent);
}

.tool-list .desc {
  font-size: 0.9rem;
  color: var(--muted);
}

label {
  display: block;
  font-weight: 600;
  margin: 12px 0 4px;
}

textarea,
input[type="number"],
select {
  width: 100%;
  padding: 10px 12px;
  font-size: 1rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
  color: var(--text);
}

textarea {
  min-height: 180px;
  resize: vertical;
}

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

.row > div {
  flex: 1;
  min-width: 120px;
}

button {
  margin-top: 16px;
  padding: 10px 24px;
  font-size: 1rem;
  font-weight: 700;
  color: #fff;
  background: var(--accent);
  border: none;
  border-radius: 8px;
  cursor: pointer;
}

button:hover {
  opacity: 0.9;
}

.result {
  margin-top: 16px;
  padding: 16px;
  background: #eff6ff;
  border-radius: 8px;
  font-size: 1.05rem;
}

.result strong {
  font-size: 1.3rem;
}

.error {
  margin-top: 16px;
  padding: 12px 16px;
  background: #fef2f2;
  color: #b91c1c;
  border-radius: 8px;
}

table.stats {
  width: 100%;
  border-collapse: collapse;
  margin-top: 16px;
}

table.stats th,
table.stats td {
  text-align: left;
  padding: 8px 12px;
  border-bottom: 1px solid var(--border);
}

table.stats td {
  text-align: right;
  font-variant-numeric: tabular-nums;
  font-weight: 700;
}

.copy-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 8px 0;
  flex-wrap: wrap;
}

.copy-label {
  min-width: 5.5em;
  color: var(--muted);
  font-size: 0.9rem;
}

.copy-row code {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 4px 12px;
  font-size: 1.05rem;
}

button.copy-btn {
  margin-top: 0;
  padding: 4px 14px;
  font-size: 0.85rem;
  background: #fff;
  color: var(--accent);
  border: 1px solid var(--accent);
}

button.copy-btn:hover {
  background: #eff6ff;
  opacity: 1;
}

details.quick summary {
  cursor: pointer;
  font-weight: 700;
}

.note {
  font-size: 0.85rem;
  color: var(--muted);
}

footer {
  border-top: 1px solid var(--border);
  padding: 24px 0;
  font-size: 0.85rem;
  color: var(--muted);
}

footer nav a {
  color: var(--muted);
  margin-right: 16px;
}

[hidden] {
  display: none !important;
}