:root {
  --color-font: #fff;
  --color-gradient-top: #778fa8;
  --color-gradient-bottom: #f7bc67;

  --font-size-body: clamp(1rem, 0.9432rem + 0.2841vw, 1.125rem); /* 16-18px */
  --font-size-body-small: calc(var(--font-size-body) * 0.8); /* 12.8-14.4px */
  --font-size-heading1: clamp(2rem, 1.0909rem + 4.5455vw, 4rem); /* 32-64px */
  --font-size-heading2: clamp(1.125rem, 0.6136rem + 2.5568vw, 2.25rem); /* 18-36px */
}

html,
body {
  height: 100%;
  min-height: 100vh;
  min-height: -webkit-fill-available;
}
body {
  margin: 0;
  width: 100%;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: center;
  background-color: var(--color-gradient-top);
  color: var(--color-font);
  font-family: 'ヒラギノ明朝 ProN', 'Hiragino Mincho ProN', 'Yu Mincho Light', 'YuMincho', 'Yu Mincho', '游明朝体', serif;
  font-size: var(--font-size-body);
}
header {
  text-align: center;
  margin: 6em 0;
}
header p {
  font-size: var(--font-size-body-small);
}
main {
  margin: 0;
}
main *:first-child {
  margin-top: 0;
}
footer {
  padding: 5em 0;
  text-align: center;
  font-size: var(--font-size-body-small);
}
p {
  margin: 0;
}
h1 {
  font-size: var(--font-size-heading1);
  text-align: center;
  margin: 0;
  letter-spacing: 0.15em;
}
h2 {
  font-size: var(--font-size-heading2);
  line-height: 1;
  margin: 1.5em 0 0;
  display: flex;
  flex-direction: row;
  justify-content: flex-start;
  align-items: flex-end;
  gap: 0.5em;
}
h2::after {
  content: '';
  display: block;
  border-bottom: 1px solid var(--color-font);
  width: 100%;
}
ul {
  margin: 1em 0 0;
  padding-left: 1em;
  list-style: none;
}
ul li {
  display: flex;
  justify-content: flex-start;
  align-items: center;
  width: 100%
}
ul li::before {
  content: '▶';
  display: block;
  margin-right: 0.5em;
}
li {
  margin-top: 0.5em;
}
li p {
  width: 100%;
}
a {
  display: block;
  padding: 0.5em;
  color: var(--color-font);
  text-decoration: none;
  border-radius: 0.3em;
  box-sizing: border-box;
}
a:hover {
  background-color: rgba(255, 255, 255, 0.2);
}
.container {
  width: fit-content;
  justify-self: center;
  margin: 0 auto;
  padding: 0 1em;
  box-sizing: border-box;
}
.vertical-gradient {
  background-image: linear-gradient(to bottom, var(--color-gradient-top), var(--color-gradient-bottom));
  background-attachment: fixed;
  background-repeat: no-repeat;
  background-size: cover;
}
.horizontal-stack {
  display: flex;
  flex-direction: row;
  justify-content: flex-start;
  align-items: center;
  gap: 0.5em;
}