:root {
  --bg: #ffffff;
  --ink: #0b3558;
  --ink-soft: #476788;
  --line: #e5e9ee;
  --hover: #eaf2ff;
  --accent: #006bff;
  --muted: #6b7280;
  --disabled: #b4bcc6;
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  min-height: 100vh;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  background: var(--bg);
  color: var(--ink);
  font-family: Inter, "Segoe UI", system-ui, -apple-system, Roboto, "Helvetica Neue", Arial, sans-serif;
  line-height: 1.5;
}

.page {
  flex: 1;
  width: 100%;
  max-width: 440px;
  margin: 0 auto;
  padding: clamp(40px, 9vh, 96px) 16px 0;
}

.intro {
  margin-bottom: 32px;
  text-align: center;
}

h1 {
  margin: 0 0 8px;
  font-size: clamp(1.75rem, 5vw, 2.25rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.intro p {
  margin: 0;
  color: var(--ink-soft);
  font-size: 1.0625rem;
}

.card {
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 20px 16px 16px;
  box-shadow: 0 1px 2px rgba(11, 53, 88, 0.04), 0 8px 24px rgba(11, 53, 88, 0.04);
}

.cal-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 12px;
}

.cal-nav { display: flex; gap: 2px; }

.cal-title {
  margin: 0;
  font-size: 1rem;
  font-weight: 600;
  text-align: center;
}

.nav-btn {
  width: 36px;
  height: 36px;
  border: 0;
  border-radius: 50%;
  background: transparent;
  color: var(--accent);
  font: inherit;
  font-size: 1.375rem;
  line-height: 1;
  cursor: pointer;
}
.nav-btn:hover:not(:disabled) { background: var(--hover); }
.nav-btn:disabled { color: var(--disabled); cursor: default; }

.cal {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  table-layout: fixed;
}

.cal th {
  padding: 8px 0;
  color: var(--ink-soft);
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.cal abbr { text-decoration: none; }

.cal td { padding: 2px; text-align: center; }

.day {
  display: block;
  width: 100%;
  aspect-ratio: 1;
  max-width: 48px;
  margin: 0 auto;
  border: 0;
  border-radius: 50%;
  background: transparent;
  color: var(--accent);
  font: inherit;
  font-size: 0.9375rem;
  font-weight: 600;
  cursor: pointer;
}
.day:hover:not(:disabled) { background: var(--hover); }
.day:disabled { color: var(--disabled); font-weight: 400; cursor: default; }
.day.is-today { box-shadow: inset 0 0 0 1px var(--line); }
.day[aria-pressed="true"],
.day[aria-pressed="true"]:hover {
  background: var(--accent);
  color: #fff;
}

.nav-btn:focus-visible,
.day:focus-visible {
  outline: 2px solid var(--ink);
  outline-offset: 2px;
}

.result {
  min-height: 88px;
  margin-top: 12px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
  text-align: center;
}
.result .when {
  margin: 0;
  color: var(--ink-soft);
  font-size: 0.875rem;
}
.result .msg {
  margin: 2px 0 0;
  font-size: 1.125rem;
  font-weight: 600;
}

.footer {
  margin-top: 96px;
  padding: 24px 16px 32px;
  text-align: center;
  font-size: 0.75rem;
}
.footer p {
  margin: 0;
  color: var(--muted);
}

@media (prefers-reduced-motion: no-preference) {
  .nav-btn, .day { transition: background-color 0.12s ease; }
}