* {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 30px;
  font-family:
    "MS PGothic",
    "ＭＳ Ｐゴシック",
    sans-serif;
  color: #fff;
  background:
    url("matrix.png") center / cover no-repeat;
  background-attachment: fixed;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;

  background:
    url("matrix.png") center / cover no-repeat,
    radial-gradient(circle at top, #003300, #000);

  filter: blur(8px);
  transform: scale(1.1); /* 端の欠け対策 */
}

.desktop {
  max-width: 900px;
  margin: auto;
}

.window {
  margin-bottom: 24px;
  background: #ece9d8;
  color: #000;
  border: 1px solid #003c74;
  box-shadow:
    2px 2px 0 #fff inset,
    -2px -2px 0 #716f64 inset,
    0 0 20px rgba(0, 255, 0, 0.15);
}

.title-bar {
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 8px;
  background:
    linear-gradient(
      to right,
      #0a246a,
      #3a6ea5,
      #7ba8e0
    );
  color: white;
  font-weight: bold;
}

.buttons {
  display: flex;
  gap: 4px;
}

.buttons span {
  width: 14px;
  height: 14px;
  background: #ece9d8;
  border:
    1px solid #ffffff
    #404040
    #404040
    #ffffff;
}

.window-body {
  padding: 20px;
}

.hero h1 {
  margin-top: 0;
  font-size: 48px;
  letter-spacing: 4px;
}

.matrix {
  color: #0000ff;
  font-family: monospace;
  font-size: 20px;
  text-shadow:
    0 0 5px #00ff00,
    0 0 10px #00ff00;
}

h2 {
  margin-top: 0;
  border-bottom: 2px dotted #666;
  padding-bottom: 6px;
}

ul {
  padding-left: 20px;
}

.red-frame {
  border: 4px solid red;
  transform: rotate(-1deg);
}

.purple-frame {
  border: 4px solid rgb(255, 0, 234);
  transform: rotate(0deg);
}

.footer {
  text-align: center;
  font-size: 14px;
  color: #444;
}

@media (max-width: 700px) {
  body {
    padding: 16px;
  }

  .hero h1 {
    font-size: 34px;
  }
}