:root {
  --color-bg: #eef3fb;
  --color-surface: #ffffff;
  --color-surface-soft: #f6f9ff;
  --color-border: #d8e2f0;
  --color-border-strong: #c4d4ea;
  --color-text: #18212f;
  --color-text-soft: #556070;
  --color-primary: #2346a2;
  --color-primary-strong: #173274;
  --color-primary-soft: #dfe9ff;
  --shadow-soft: 0 16px 40px rgba(25, 42, 70, 0.08);
  --shadow-card: 0 10px 24px rgba(25, 42, 70, 0.08);
  --radius-lg: 20px;
  --radius-md: 14px;
  --radius-sm: 10px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Segoe UI", "Hiragino Sans", "Yu Gothic UI", "Meiryo", sans-serif;
  line-height: 1.7;
  color: var(--color-text);
  background:
    radial-gradient(circle at top left, rgba(35, 70, 162, 0.18), transparent 34%),
    radial-gradient(circle at top right, rgba(59, 130, 246, 0.12), transparent 30%),
    linear-gradient(180deg, #e7eef9 0%, #dfe8f5 42%, #d6e1f0 100%);
  min-height: 100vh;
  background-attachment: fixed;
}

img {
  max-width: 100%;
}

a {
  color: inherit;
  text-decoration-color: rgba(35, 70, 162, 0.28);
  text-underline-offset: 0.18em;
}

a:hover {
  color: var(--color-primary);
}

button,
input,
select,
textarea {
  font: inherit;
}

mark {
  padding: 0.15em 0.38em;
  border-radius: 999px;
  background: #fff0a8;
  color: var(--color-primary-strong);
}

::selection {
  background: rgba(35, 70, 162, 0.16);
}

:focus-visible {
  outline: 3px solid rgba(35, 70, 162, 0.24);
  outline-offset: 2px;
}