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

body {
  font-family: "Microsoft YaHei", sans-serif;
  background: #f5f7fa;
  color: #333;
  line-height: 1.6;
  padding-bottom: 180px;
  padding-top: 60px;
}

/* 顶部导航（固定结构，不要改） */
.top-bar {
  background: #fff;
  padding: 10px 20px;
  border-bottom: 1px solid #eee;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 99999;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.home-btn {
  color: #409eff;
  text-decoration: none;
  font-size: 14px;
}

.lang-buttons {
  display: flex;
  gap: 8px;
}

.lang-btn {
  border: 1px solid #ddd;
  background: #fff;
  padding: 5px 12px;
  border-radius: 4px;
  text-decoration: none;
  color: #333;
  font-size: 14px;
}

.lang-btn.active {
  background: #409eff;
  color: #fff;
  border-color: #409eff;
}

.lang-btn:hover {
  background: #f0f0f0;
}

/* 主体容器（固定结构，不要改） */
.container {
  max-width: 800px;
  margin: 40px auto;
  padding: 0 20px;
}

h1 {
  font-size: 24px;
  margin-bottom: 8px;
  color: #222;
  text-align: center;
}

#toolDesc {
  text-align: center;
  color: #666;
  margin-bottom: 30px;
  font-size: 15px;
}

/* --------------------- 【可修改区域：工具样式】 --------------------- */
.calc-box {
  background: #fff;
  padding: 30px;
  border-radius: 12px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.06);
}

input[type="number"],
input[type="text"],
select {
  width: 100%;
  padding: 12px 15px;
  border: 1px solid #ddd;
  border-radius: 6px;
  font-size: 16px;
  outline: none;
  margin: 10px 0;
}

button {
  width: 100%;
  padding: 12px;
  margin: 8px 0;
  border: none;
  border-radius: 6px;
  background: #409eff;
  color: #fff;
  font-size: 16px;
  cursor: pointer;
}

#btnClear {
  background: #909399;
}

button:hover {
  background: #338eef;
}