:root {
  color-scheme: light;
  --ink: #202124;
  --muted: #687078;
  --line: #e8ebef;
  --accent: #335cff;
  --paper: #ffffff;
  --canvas: #f1f3f7;
}

* {
  box-sizing: border-box;
}

html {
  background: var(--canvas);
}

body {
  max-width: 760px;
  margin: 32px auto;
  padding: 46px 56px 64px;
  background: var(--paper);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Noto Sans CJK SC", "Microsoft YaHei", sans-serif;
  font-size: 17px;
  line-height: 1.9;
  letter-spacing: 0.015em;
  box-shadow: 0 16px 48px rgba(31, 42, 68, 0.08);
}

h1 {
  margin: 0 0 28px;
  font-size: 31px;
  line-height: 1.35;
  letter-spacing: -0.02em;
}

h2 {
  margin: 52px 0 18px;
  font-size: 23px;
  line-height: 1.45;
}

p {
  margin: 17px 0;
}

a {
  color: var(--accent);
  text-decoration: none;
  overflow-wrap: anywhere;
}

strong {
  color: #11131a;
}

blockquote {
  margin: 28px 0;
  padding: 18px 22px;
  border-left: 4px solid var(--accent);
  background: #f6f8ff;
  color: #3d4652;
}

blockquote p {
  margin: 0;
}

img,
video {
  display: block;
  width: 100%;
  height: auto;
  margin: 26px auto;
  border-radius: 12px;
}

.video-card {
  margin: 30px 0 38px;
}

.video-card video {
  margin: 0;
  background: #0f1115;
  box-shadow: 0 12px 30px rgba(15, 17, 21, 0.13);
}

.video-card figcaption {
  margin-top: 10px;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.6;
  text-align: center;
}

.paper-caption {
  margin: -12px 8px 30px;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.65;
  text-align: center;
}

hr {
  height: 1px;
  margin: 44px 0;
  border: 0;
  background: var(--line);
}

@media (max-width: 720px) {
  html {
    background: var(--paper);
  }

  body {
    margin: 0;
    padding: 28px 20px 48px;
    font-size: 16px;
    box-shadow: none;
  }

  h1 {
    font-size: 27px;
  }

  h2 {
    margin-top: 44px;
    font-size: 21px;
  }
}