* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: "STKaiti", "KaiTi", "楷体", Georgia, serif;
  background-color: #2b2520;
  color: #e8dcc8;
  line-height: 1.8;
  padding: 40px 20px;
}

.container {
  max-width: 960px;
  margin: 0 auto;
  background-color: #3d3630;
  padding: 40px 50px;
  box-shadow: 0 2px 30px rgba(0, 0, 0, 0.5);
  border: 1px solid #4a4035;
}

.toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  margin-bottom: 20px;
}

.back-link {
  color: #c9b896;
  text-decoration: none;
  border: 1px solid #6b5d4f;
  padding: 6px 12px;
  transition: all 0.3s ease;
}

.back-link:hover {
  background-color: #4a4238;
  border-color: #c9b896;
}

.language-switch {
  text-align: right;
}

.lang-btn {
  display: inline-block;
  padding: 6px 12px;
  margin-left: 6px;
  color: #c9b896;
  background-color: transparent;
  border: 1px solid #6b5d4f;
  cursor: pointer;
  transition: all 0.3s ease;
  font-family: "STKaiti", "KaiTi", "楷体", Georgia, serif;
}

.lang-btn:hover {
  background-color: #4a4238;
  border-color: #c9b896;
}

.lang-btn.active {
  background-color: #6b5d4f;
  color: #f5ecd7;
}

header {
  text-align: center;
  margin-bottom: 30px;
  padding-bottom: 20px;
  border-bottom: 2px solid #6b5d4f;
}

h1 {
  font-size: 2.3rem;
  font-weight: normal;
  color: #f5ecd7;
  margin-bottom: 10px;
  letter-spacing: 4px;
}

.subtitle {
  color: #c9b896;
  letter-spacing: 2px;
}

.status {
  margin-bottom: 16px;
  color: #c9b896;
}

.status.error {
  color: #e0a39a;
}

.markdown-content {
  color: #e8dcc8;
}

.markdown-content h1,
.markdown-content h2,
.markdown-content h3,
.markdown-content h4 {
  color: #f5ecd7;
  margin: 18px 0 8px;
}

.markdown-content p,
.markdown-content li,
.markdown-content blockquote {
  color: #d4c5b0;
}

.markdown-content ul,
.markdown-content ol {
  margin: 8px 0 12px 24px;
}

.markdown-content blockquote {
  border-left: 3px solid #6b5d4f;
  padding-left: 12px;
  margin: 10px 0;
}

.markdown-content hr {
  border: none;
  border-top: 1px solid #6b5d4f;
  margin: 18px 0;
}

.markdown-content code {
  background-color: #2f2923;
  padding: 1px 4px;
  border-radius: 4px;
}

.markdown-content pre {
  background-color: #2f2923;
  border: 1px solid #564d42;
  padding: 12px;
  overflow-x: auto;
  margin: 12px 0;
}

.markdown-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 14px 0;
}

.markdown-content th,
.markdown-content td {
  border: 1px solid #564d42;
  padding: 8px;
  text-align: left;
}

.markdown-content th {
  background-color: #4a4238;
}

.markdown-content .math-inline {
  display: inline-block;
  white-space: nowrap;
  font-family: "Times New Roman", "Cambria Math", serif;
  color: #f5ecd7;
}

.markdown-content .math-block {
  display: block;
  text-align: center;
  margin: 10px 0;
  overflow-x: auto;
  font-family: "Times New Roman", "Cambria Math", serif;
  color: #f5ecd7;
}

.markdown-content .math-frac {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  line-height: 1.1;
  vertical-align: middle;
  margin: 0 2px;
}

.markdown-content .math-num {
  border-bottom: 1px solid #c9b896;
  padding: 0 3px 2px;
}

.markdown-content .math-den {
  padding: 2px 3px 0;
}

@media (max-width: 768px) {
  .container {
    padding: 30px 20px;
  }

  .toolbar {
    flex-direction: column;
    align-items: flex-start;
  }

  h1 {
    font-size: 1.9rem;
  }
}