* {
  box-sizing: border-box;
}

:root {
  --bg: #f5f7fb;
  --card: #ffffff;
  --text: #1f2430;
  --muted: #5a6273;
  --line: #d8deea;
  --link: #0b63f3;
  --link-hover: #084fc5;
  --accent: #e9f0ff;
  --shadow: 0 10px 28px rgba(19, 35, 66, 0.08);
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Yu Gothic", Meiryo, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
}

a {
  color: var(--link);
  text-decoration: none;
}

a:hover {
  color: var(--link-hover);
  text-decoration: underline;
}

.container {
  width: min(1080px, 100% - 32px);
  margin: 0 auto;
}

.header {
  border-bottom: 1px solid var(--line);
  background: #ffffff;
}

.header-inner {
  min-height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand {
  font-size: 22px;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  font-size: 14px;
}

.main {
  padding: 28px 0 48px;
}

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
  box-shadow: var(--shadow);
  padding: 24px;
}

.card + .card {
  margin-top: 18px;
}

h1,
h2,
h3 {
  margin: 0;
  line-height: 1.3;
  letter-spacing: -0.01em;
}

h1 {
  font-size: clamp(28px, 4vw, 40px);
}

h2 {
  margin-top: 20px;
  font-size: clamp(22px, 3vw, 30px);
}

h3 {
  margin-top: 14px;
  font-size: 21px;
}

p,
ul,
ol {
  margin: 12px 0 0;
}

ul,
ol {
  padding-left: 20px;
}

.meta {
  color: var(--muted);
  font-size: 14px;
}

.grid {
  margin-top: 16px;
  display: grid;
  gap: 14px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.item {
  border: 1px solid var(--line);
  border-radius: 12px;
  background: #fcfdff;
  padding: 16px;
}

.label {
  display: inline-block;
  font-size: 12px;
  color: #2453b8;
  background: var(--accent);
  border: 1px solid #c9d8ff;
  border-radius: 999px;
  padding: 3px 10px;
}

.actions {
  margin-top: 12px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.btn {
  display: inline-block;
  padding: 8px 14px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: #ffffff;
}

.btn.primary {
  border-color: #2f6eed;
  background: #2f6eed;
  color: #ffffff;
}

.footer {
  padding: 0 0 38px;
  color: var(--muted);
  font-size: 13px;
}

@media (max-width: 820px) {
  .grid {
    grid-template-columns: 1fr;
  }

  .header-inner {
    min-height: 0;
    padding: 14px 0;
    align-items: flex-start;
    flex-direction: column;
  }
}