html { 
    scroll-behavior: smooth;  
}

:root {
    --bg-color: #ffffff;
    --text-color: #333333;
    --link-color: #1a0dab;
    --button-bg: #e0e0e0; /* darker light-mode button background */
    --button-text: #333333;
    --transition-time: 0.3s;
}

/* 暗色主题变量 */
.dark-mode {
    --bg-color: #1a1a1a;
    --text-color: #f0f0f0;
    --button-bg: #333333;
    --button-text: #f0f0f0;
    --link-color: #0099ff;
}

a {
    color: var(--link-color);
    transition: color var(--transition-time);
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: 
        background-color var(--transition-time),
        color var(--transition-time);
}

/* 自动适应系统主题设置 */
@media (prefers-color-scheme: dark) {
    :root:not(.light-mode) {
        --bg-color: #ffffff;
        --text-color: #000000;
    }
}

.button-link {
  font-size: 24px;
  padding: 15px 30px;
  background-color: var(--button-bg);
  color: var(--button-text);
  border: 1px solid var(--border-color, #999);
  border-radius: 8px;
  cursor: pointer;
  display: inline-block; /* More compatible than inline-flex on older devices */
  text-align: center;
  transition: background-color var(--transition-time), color var(--transition-time), border-color var(--transition-time);
}

.button-link img {
  width: 32px;
  height: auto;
  vertical-align: middle;
  margin-right: 10px;
}


.button-func {
  font-size: 16px;
  padding: 15px 30px;
  background-color: var(--button-bg);
  color: var(--button-text);
  border: 1px solid #999; /* Added border */
  border-radius: 5px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  transition: background-color var(--transition-time), color var(--transition-time), border-color var(--transition-time);
}


/* 弹窗 */
.popup {
    display: none;
    position: fixed;
    z-index: 999;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5); /* 半透明 */
}

/* 弹窗内容 */
.popup-content {
    background-color: white; /* Fallback for old devices */
    background: var(--bg-color, white); /* CSS variable for modern browsers */
    position: relative;
    margin: 10% auto;
    padding: 20px;
    width: 90%;
    max-width: 500px;
    max-height: 50vh;
    overflow-y: auto;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.3);
}


/* 关闭按钮 */
.close-btn {
    position: absolute;
    top: 10px;
    right: 15px;
    font-size: 20px;
    cursor: pointer;
    color: #aaa;
}

.close-btn:hover {
    color: #000;
}