:root {
  --color-paper: #ffffff;
  --color-surface: #f7f8fa;
  --color-ink: #1f2937;
  --color-muted: #667085;
  --color-line: #e5e7eb;
  --color-accent: #2563eb;
  --color-accent-dark: #1d4ed8;
  --content-width: 1080px;
  --side-space: clamp(1.25rem, 3vw, 2.5rem);
}

* {
  box-sizing: border-box;
}

html {
  min-width: 0;
  background: var(--color-paper);
  color: var(--color-ink);
  font-family: "Inter", "Noto Sans JP", sans-serif;
}

body {
  min-height: 100vh;
  margin: 0;
  display: grid;
  grid-template-rows: auto 1fr auto;
  background: var(--color-surface);
}

a {
  color: inherit;
}

a:focus-visible {
  outline: 3px solid var(--color-accent);
  outline-offset: 5px;
}

.site-header {
  background: linear-gradient(90deg, var(--color-accent-dark), var(--color-accent));
  color: #ffffff;
  box-shadow: 0 1px 3px rgb(15 23 42 / 18%);
}

.site-header__inner {
  width: min(100%, var(--content-width));
  margin-inline: auto;
  min-height: 4rem;
  padding: 0.75rem var(--side-space);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
}

.site-name {
  font-size: 1.125rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-decoration: none;
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0.5rem;
  font-size: 0.8125rem;
  font-weight: 500;
}

.site-nav a {
  border-radius: 0.375rem;
  padding: 0.5rem 0.75rem;
  text-decoration: none;
  transition: background-color 160ms ease;
}

.site-nav a:hover {
  background: rgb(255 255 255 / 12%);
}

.site-nav a[aria-current="page"] {
  background: rgb(255 255 255 / 20%);
}

.page-main {
  width: min(100%, var(--content-width));
  margin: clamp(1rem, 3vw, 2rem) auto;
  padding: clamp(2rem, 5vw, 4rem) var(--side-space);
  background: var(--color-paper);
  border: 1px solid var(--color-line);
  border-radius: 0.625rem;
  box-shadow: 0 1px 2px rgb(15 23 42 / 5%);
}

.page-main--home {
  display: grid;
  place-items: center;
  text-align: center;
}

h1 {
  margin: 0;
  color: var(--color-ink);
  font-size: clamp(2.5rem, 8vw, 6rem);
  font-weight: 600;
  letter-spacing: 0.04em;
  line-height: 1.15;
}

.page-main:not(.page-main--home) h1 {
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--color-line);
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  letter-spacing: 0.02em;
}

.empty-panel {
  min-height: 14rem;
  margin-top: 1.5rem;
  padding: 1.5rem;
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: 0.5rem;
}

.empty-panel h2 {
  margin: 0 0 1rem;
  color: var(--color-accent);
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.08em;
}

.operator-name {
  margin: 0;
  font-size: clamp(1.25rem, 3vw, 1.75rem);
  font-weight: 500;
  letter-spacing: 0.04em;
}

.site-footer {
  width: min(100%, var(--content-width));
  margin-inline: auto;
  padding: 1rem var(--side-space) 1.5rem;
  color: var(--color-muted);
  font-size: 0.75rem;
  letter-spacing: 0.04em;
}

.site-footer p {
  margin: 0;
}

@media (max-width: 767px) {
  .site-header__inner {
    align-items: stretch;
    flex-direction: column;
    gap: 0.5rem;
    padding-block: 0.875rem;
  }

  .site-nav {
    justify-content: flex-start;
    gap: 0.25rem;
  }

  .page-main {
    width: calc(100% - 1.5rem);
    margin-block: 0.75rem;
    padding: 2rem 1.25rem;
  }

  .page-main--home {
    place-items: start;
    text-align: left;
  }

  h1 {
    overflow-wrap: anywhere;
  }
}