:root {
  --bg: #f5f7fa;
  --surface: #ffffff;
  --text: #1c2530;
  --muted: #5c6b7a;
  --border: #e2e8f0;
  --brand: #c8102e;
  --brand-dark: #9c0c24;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.08), 0 6px 20px rgba(0, 0, 0, 0.05);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Hiragino Sans", "Noto Sans JP",
    "Meiryo", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
}

.container {
  width: min(880px, 92vw);
  margin-inline: auto;
}

code {
  background: rgba(0, 0, 0, 0.06);
  padding: 0.1em 0.4em;
  border-radius: 4px;
  font-size: 0.9em;
}

/* Hero */
.hero {
  background: linear-gradient(135deg, var(--brand), var(--brand-dark));
  color: #fff;
  padding: 4rem 0 3rem;
}

.eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.15em;
  font-size: 0.8rem;
  opacity: 0.85;
  margin: 0 0 0.5rem;
}

.hero h1 {
  margin: 0 0 0.75rem;
  font-size: clamp(2.2rem, 6vw, 3.2rem);
  letter-spacing: 0.02em;
}

.lead {
  margin: 0;
  max-width: 40rem;
  font-size: 1.05rem;
}

.hero code {
  background: rgba(255, 255, 255, 0.2);
}

/* Cards */
main {
  padding: 2.5rem 0 3rem;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.75rem;
  margin-bottom: 1.5rem;
}

.card h2 {
  margin-top: 0;
  font-size: 1.35rem;
}

/* Buttons */
.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin: 1.25rem 0;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.65rem 1.25rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  font: inherit;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: transform 0.05s ease, background 0.15s ease, border-color 0.15s ease;
}

.btn:hover {
  border-color: var(--brand);
}

.btn:active {
  transform: translateY(1px);
}

.btn-primary {
  background: var(--brand);
  border-color: var(--brand);
  color: #fff;
}

.btn-primary:hover {
  background: var(--brand-dark);
  border-color: var(--brand-dark);
}

/* URL box */
.url-box {
  margin-top: 1.5rem;
}

.url-box label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--muted);
  margin-bottom: 0.4rem;
}

.url-row {
  display: flex;
  gap: 0.5rem;
}

.url-row input {
  flex: 1;
  padding: 0.6rem 0.75rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  font: inherit;
  font-size: 0.9rem;
  background: #fbfcfe;
  color: var(--text);
}

.btn-copy {
  white-space: nowrap;
}

.hint {
  font-size: 0.85rem;
  color: var(--muted);
  margin: 0.5rem 0 0;
}

/* Help */
.help {
  margin-top: 1.5rem;
  border-top: 1px solid var(--border);
  padding-top: 1rem;
}

.help summary {
  cursor: pointer;
  font-weight: 600;
}

.help ul {
  margin: 0.75rem 0 0;
  padding-left: 1.25rem;
}

.help li {
  margin-bottom: 0.4rem;
}

/* Table */
.holidays {
  width: 100%;
  border-collapse: collapse;
  margin-top: 0.5rem;
}

.holidays th,
.holidays td {
  text-align: left;
  padding: 0.6rem 0.75rem;
  border-bottom: 1px solid var(--border);
}

.holidays th {
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--muted);
}

.holidays tbody tr:hover {
  background: #fbfcfe;
}

.holidays td.sun {
  color: var(--brand);
}

.holidays td.sat {
  color: #2563eb;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 1.5rem 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.site-footer p {
  margin: 0;
}