* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body {
  font-family: "Linux Libertine", Georgia, serif;
  background: #fefefe;
  color: #000;
  line-height: 1.6;
}
#category-header {
  background: #f8f9fa;
  border-bottom: 1px solid #ccc;
  padding: 10px 20px;
  position: sticky;
  top: 0;
  z-index: 1000;
}
#category-header ul {
  list-style: none;
  display: flex;
  gap: 20px;
  align-items: center;
  margin: 0;
  padding: 0;
  justify-content: flex-end;
}
#category-header li {
  cursor: pointer;
  font-size: 16px;
  color: #336699;
}
#category-header li.active {
  font-weight: bold;
  border-bottom: 2px solid #336699;
}
#category-header li:hover {
  text-decoration: underline;
}
.article-title {
  font-family: "Linux Libertine", Georgia, serif;
  font-size: 28px;
  font-weight: 200;
  color: rgb(16, 20, 24);
  margin: 0 20px;
  border-bottom: 1px solid #ddd;
  background: #fff;
}
#articles-container {
  max-width: 800px;
  margin: 0 auto;
}
.article-frame-container {
  width: 100%;
  height: 600px;
  margin: 20px auto;
  overflow: hidden;
  position: relative;
}
.article-content {
  width: 100%;
}
.article-iframe {
  width: 100%;
  border: none;
  margin-top: -225px;
  transition: height 0.2s ease-out;
  will-change: transform;
}
.placeholder {
  background: #fafafa;
  border: 1px solid #f0f0f0;
  width: 100%;
  will-change: transform;
}
.expand-button {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  background: rgba(252, 252, 252, 0.85);
  border: 1px solid #eee;
  padding: 4px;
  cursor: pointer;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: rgba(102, 102, 102, 0.3);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  opacity: 0.8;
}
.expand-button:hover {
  background: rgba(248, 249, 250, 1);
  color: rgba(102, 102, 102, 1);
  opacity: 1;
}
#loading {
  position: fixed;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
}
.spinner svg {
  width: 50px;
  height: 50px;
  animation: rotate 2s linear infinite;
}
.spinner .path {
  stroke: #0078D7;
  stroke-linecap: round;
  animation: dash 1.5s ease-in-out infinite;
}
.hidden {
  display: none;
}
.article-wrapper {
  will-change: transform;
  transform: translateZ(0);
}
@media screen and (max-width: 768px) {
  .article-iframe {
    margin-top: -245px;
  }
  .article-frame-container {
    height: 100vh;
  }
  .article-iframe {
    height: calc(100vh + 245px);
  }
}
@keyframes rotate {
  100% {
    transform: rotate(360deg);
  }
}
@keyframes dash {
  0% {
    stroke-dasharray: 1, 150;
    stroke-dashoffset: 0;
  }
  50% {
    stroke-dasharray: 90, 150;
    stroke-dashoffset: -40;
  }
  100% {
    stroke-dasharray: 90, 150;
    stroke-dashoffset: -120;
  }
}