/* 全局样式 */
body {
  font-family: "Segoe UI", Roboto, sans-serif;
  margin: 0;
  padding: 0;
  background: #f4f6f8;
  color: #051d40;
  font-size: clamp(1rem, 1.5vw, 1.4rem); /* 自动缩放，最小1rem，最大1.4rem */
}

/* 顶部导航 */
header {
  background: #051d40;
  width: 100%;
  color: #fff;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: clamp(1rem, 1.5vw, 1.4rem);
}

header h1 {
  margin: 2rem;
  font-size: clamp(1.2rem, 1.6vw, 2.0rem);
}

nav a {
  color: #fff;
  margin-left: 1.5rem;
  text-decoration: none;
  font-weight: 700;
  transition: color 0.3s ease;
  font-size: clamp(1rem, 1.5vw, 1.4rem);
}

nav a:hover {
  color: #00DAEA;
}

/* 主内容区 */
main {
  max-width: 1000px;
  margin: 2rem auto;
  padding: 0 1rem;
  font-size: clamp(1rem, 1.5vw, 1.4rem);
}

/* 帖子卡片 */
.post-card {
  background: #fff;
  border-radius: 8px;
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.08);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  font-size: clamp(1rem, 1.5vw, 1.4rem);
}

.post-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 6px 16px rgba(0, 0, 0, 0.15);
}

.post-card h2 {
  margin: 0 0 0.5rem;
  font-size: clamp(1.25rem, 1.8vw, 2.2rem);
}

.post-card h2 a {
  text-decoration: none;
  color: #051d40;
  transition: color 0.2s ease;
}

.post-card h2 a:hover {
  color: #00DAEA;
}

.post-card .meta {
  font-size: clamp(0.8rem, 1vw, 1.0rem);
  color: #777;
  margin-bottom: 0.75rem;
}

.post-card .content-preview {
  line-height: 1.6;
}

/* 页脚 */
footer {
  background: #051d40;
  color: #fff;
  text-align: center;
  padding: 1rem;
  margin-top: 3rem;
  font-size: clamp(0.9rem, 1.5vw, 2.0rem);
}

/* 评论卡片 */
.comment-card {
  background: #fafafa;
  border: 1px solid #ddd;
  border-radius: 6px;
  padding: 1rem;
  margin-bottom: 1rem;
  font-size: clamp(1rem, 1.5vw, 2.0rem);
}

.comment-meta {
  font-size: clamp(0.8rem, 1.5vw, 2.0rem);
  color: #777;
  display: block;
  margin-top: 0.5rem;
}

/* 评论表单 */
.comment-form {
  margin-top: 1.5rem;
  display: flex;
  flex-direction: column;
  font-size: clamp(1rem, 1.5vw, 1.8rem);
}

.comment-form textarea {
  resize: vertical;
  padding: 0.75rem;
  border: 1px solid #ccc;
  border-radius: 6px;
  font-size: clamp(1rem, 1.5vw, 1.8rem);
  margin-bottom: 0.75rem;
}

.comment-form button {
  align-self: flex-end;
  padding: 0.5rem 1.5rem;
  background: #051d40;
  color: #fff;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: background 0.3s ease;
  font-size: clamp(1rem, 1.5vw, 1.8rem);
}

.comment-form button:hover {
  background: #00DAEA;
}

/* 新帖表单 */
.form-card {
  background: #fff;
  border-radius: 8px;
  padding: 2rem;
  box-shadow: 0 2px 6px rgba(0,0,0,0.1);
  max-width: 600px;
  margin: 2rem auto;
  font-size: clamp(1rem, 1.5vw, 1.8rem);
}

.form-card h2 {
  margin-bottom: 1rem;
  font-size: clamp(1.4rem, 1.8vw, 2.4rem);
}

.form-card label {
  display: block;
  margin-top: 1rem;
  margin-bottom: 0.5rem;
  font-weight: 500;
  font-size: clamp(1rem, 1.5vw, 1.8rem);
}

.form-card input,
.form-card textarea {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid #ccc;
  border-radius: 6px;
  font-size: clamp(1rem, 1.5vw, 1.8rem);
}

.form-card button {
  margin-top: 1.5rem;
  padding: 0.75rem 2rem;
  background: #051d40;
  color: #fff;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: background 0.3s ease;
  font-size: clamp(1rem, 1.5vw, 1.8rem);
}

.form-card button:hover {
  background: #00DAEA;
}

.error {
  color: red;
  margin-bottom: 1rem;
  font-size: clamp(0.9rem, 1.5vw, 1.8rem);
}

/* 分页 */
.pagination {
  text-align: center;
  margin: 20px 0;
  font-size: clamp(1rem, 1.5vw, 1.8rem);
}

.pagination a, .pagination span {
  display: inline-block;
  padding: 6px 12px;
  margin: 0 3px;
  border-radius: 4px;
  text-decoration: none;
  color: #0073e6;
  border: 1px solid #ddd;
  transition: background 0.3s;
}

.pagination a:hover {
  background: #0073e6;
  color: white;
}

.pagination .current {
  background: #0073e6;
  color: white;
  border-color: #0073e6;
}

/* 响应式优化 */
@media (max-width: 768px) {
  header {
    flex-direction: column;
    align-items: flex-start;
  }

  nav {
    margin-top: 0.5rem;
  }

  nav a {
    margin-left: 0;
    margin-right: 1rem;
  }

  .post-card {
    padding: 1rem;
  }

  .post-card h2 {
    font-size: clamp(1rem, 1.3vw, 1.6rem);
  }
}