/* 页面整体样式 */
body {
  margin: 0;
  padding: 0;
 font-family: "Noto Sans SC", "Noto Serif SC", sans-serif;
  background: linear-gradient(180deg, #eaf3ff, #d8e9ff); /* 淡蓝背景 */
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding-top: 40px;
  position: relative; /* 为右下角按钮定位 */
}

/* 外层信封样式 */
.mail-wrapper {
  background: #ffffff;
  width: 680px;
  border-radius: 10px;
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.1);
  overflow: hidden;
  border: 1px solid #d0e2ff;
  position: relative;
  z-index: 1;
}

/* 顶部标题栏 */
header {
  background: #f4f8ff;
  border-bottom: 1px solid #c9dcff;
  padding: 20px 30px;
}

header h1 {
  margin: 0;
  color: #2a63c2;
  font-size: 1.6rem;
}

header h2 {
  margin: 8px 0 4px;
  color: #3a3a3a;
  font-weight: normal;
  font-size: 1rem;
}

header h3 {
  margin: 4px 0 0;
  color: #5a75a6;
  font-weight: 500;
  font-size: 1rem;
}

/* 邮件正文区域 */
.mail-content {
  padding: 28px 40px;
  line-height: 1.9;
  color: #222;
  font-size: 1.05rem;
}

.mail-content p {
  margin: 14px 0;
}

/* 链接样式 */
.mail-content a {
  color: #2a63c2;
  text-decoration: none;
  font-weight: 500;
}

.mail-content a:hover {
  text-decoration: underline;
}

/* 签名部分 */
.signature {
  margin-top: 28px;
  text-align: right;
  color: #444;
  font-weight: 500;
}

/* 右下角登录邮箱按钮 */
.login-tab {
  position: fixed;
  bottom: 20px;
  right: 20px;
  background-color: #2a63c2;
  color: #fff;
  padding: 12px 22px;
  border-radius: 8px 8px 8px 8px; /* 或简写成 8px */
  font-weight: 600;
  cursor: pointer;
  text-decoration: none;
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
  transition: all 0.3s ease;
  z-index: 1000;
}

.login-tab:hover {
  background-color: #1f4aa3;
  transform: translateY(-2px);
}

/* 响应式 */
@media (max-width: 500px) {
  .mail-wrapper {
    width: calc(100% - 40px);
  }
  .mail-content {
    padding: 20px;
  }
  .login-tab {
    padding: 10px 18px;
    font-size: 0.9rem;
  }
}