:root {
  --bg: #0d0f12;
  --fg: #e6edf3;

  --math-color: #7cffb3;
  --sec-color: #ff2d55;
}

body {
  margin: 0;
  background: #0d0f12;
  color: var(--fg);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Fira Code", monospace;
  line-height: 1.65;
}

.container {
  max-width: 820px;
  margin: 64px auto;
  padding: 0 24px;
  text-align: left;
}

h1 {
  margin: 0 0 14px;
  font-size: clamp(1.4rem, 1.1rem + 1.2vw, 2rem);
  font-weight: 700;
  color: #fff;
}

p {
  margin: 0 0 16px;
  font-size: 1.05rem;
  color: var(--fg);
}

/* 链接按钮基础样式 */
a {
  display: inline-block;
  margin-right: 12px;
  margin-top: 12px;
  padding: 0.6rem 1.2rem;
  font-size: 1rem;
  font-weight: 600;
  text-decoration: none;
  color: var(--fg);
  border-radius: 10px;
  background: rgba(255, 255, 255, 0.04);
  backdrop-filter: blur(4px);
  transition: all 0.3s ease;
}

/* Mathematics 按钮：绿色边框 */
a[href*="math"] {
  border: 2px solid var(--math-color);
}
a[href*="math"]:hover {
  color: var(--math-color);
  background: rgba(124, 255, 179, 0.08);
  box-shadow: 0 0 12px rgba(124, 255, 179, 0.5);
}

/* Security 按钮：红色边框 */
a[href*="security"] {
  border: 2px solid var(--sec-color);
}
a[href*="security"]:hover {
  color: var(--sec-color);
  background: rgba(255, 45, 85, 0.08);
  box-shadow: 0 0 12px rgba(255, 45, 85, 0.5);
}

/* 普通正文链接：不加 padding/margin，不改 display */
.container p a {
  text-decoration: underline;
  text-underline-offset: 2px;
  padding: 0;
  margin: 0;
  display: inline;
  border: 0;
  background: none;
  box-shadow: none;
}

/* 只给按钮样式 */
.links .btn {
  display: inline-block;
  margin-right: 12px;
  margin-top: 8px;        /* 想更紧凑可再小一点或设为0 */
  padding: 0.5rem 1rem;   /* 想更紧凑可再小一点 */
  font-weight: 600;
  text-decoration: none;
  color: var(--fg);
  border-radius: 10px;
  background: rgba(255,255,255,0.04);
  backdrop-filter: blur(4px);
  transition: all .3s ease;
}

/* 保留你对两类按钮的配色 */
.links .btn[href*="math"]     { border: 2px solid var(--math-color); }
.links .btn[href*="math"]:hover {
  color: var(--math-color);
  background: rgba(124,255,179,.08);
  box-shadow: 0 0 12px rgba(124,255,179,.5);
}
.links .btn[href*="security"] { border: 2px solid var(--sec-color); }
.links .btn[href*="security"]:hover {
  color: var(--sec-color);
  background: rgba(255,45,85,.08);
  box-shadow: 0 0 12px rgba(255,45,85,.5);
}