/* 基础变量 */
:root {
    --lang-primary: #007AFF;
    /* iOS 蓝 */
    --lang-bg: rgba(255, 255, 255, 0.95);
    /* Increased opacity */
    --lang-text: #1c1c1e;
    --lang-radius: 20px;
    --lang-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
}

/* 1. 触发按钮样式 */
.lang-trigger {
    position: fixed;
    top: 120px;
    right: 30px;
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 12px 16px;
    background: var(--lang-bg);
    border: 2px solid #ffffff !important;
    /* Force solid white border */
    border-radius: 50px;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.2);
    backdrop-filter: blur(10px);
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
    z-index: 9999;
    font-weight: 700;
    color: var(--lang-text);
    -webkit-tap-highlight-color: transparent;
}

.lang-trigger:active {
    transform: scale(0.96);
}

/* 2. 遮罩层 */
.lang-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.4);
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s;
    z-index: 10000;
}

.lang-overlay.open {
    opacity: 1;
    visibility: visible;
}

/* 3. 菜单主体 (Bottom Sheet 风格) */
.lang-menu {
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    background: var(--lang-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-top-left-radius: var(--lang-radius);
    border-top-right-radius: var(--lang-radius);
    padding: 20px 0 40px 0;
    transform: translateY(100%);
    transition: transform 0.3s cubic-bezier(0.2, 0.8, 0.2, 1);
    z-index: 10001;
    box-shadow: var(--lang-shadow);
}

.lang-menu.open {
    transform: translateY(0);
}

/* 标题栏 */
.lang-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 24px 16px 24px;
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
    margin-bottom: 10px;
    color: #8e8e93;
    font-size: 0.9rem;
    font-weight: 600;
}

.close-btn {
    background: none;
    border: none;
    font-size: 24px;
    color: var(--lang-text);
    cursor: pointer;
    padding: 5px;
}

/* 语言列表 */
.lang-list {
    list-style: none;
    padding: 0 16px;
    margin: 0;
}

.lang-option {
    width: 100%;
    display: flex;
    align-items: center;
    padding: 14px 16px;
    border: none;
    background: transparent;
    border-radius: 12px;
    cursor: pointer;
    font-size: 16px;
    color: var(--lang-text);
    transition: background 0.2s;
    text-align: left;
}

.lang-option:active {
    background: rgba(0, 0, 0, 0.05);
}

.lang-option .flag {
    font-size: 20px;
    margin-right: 12px;
    width: 24px;
    display: inline-block;
    text-align: center;
}

.lang-option img {
    width: 24px;
    height: auto;
    vertical-align: middle;
}

.lang-option .name {
    flex-grow: 1;
    font-weight: 500;
}

.lang-option .check-icon {
    opacity: 0;
    color: var(--lang-primary);
    font-weight: bold;
    transform: scale(0.5);
    transition: all 0.2s;
}

/* 选中状态 */
.lang-option.active {
    background: rgba(0, 122, 255, 0.1);
}

.lang-option.active .check-icon {
    opacity: 1;
    transform: scale(1);
}

/* --- 桌面端适配 (Media Query) --- */
@media (min-width: 768px) {
    .lang-menu {
        width: 300px;
        top: 180px;
        /* Below button */
        bottom: auto;
        right: 30px;
        left: auto;
        border-radius: var(--lang-radius);
        transform: translateY(-20px);
        opacity: 0;
        visibility: hidden;
        padding-bottom: 10px;
    }

    .lang-menu.open {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .lang-option:hover {
        background: rgba(0, 0, 0, 0.03);
    }

    .close-btn {
        display: none;
    }
}

/* Mobile Responsiveness for Button Position */
@media (max-width: 768px) {
    .lang-trigger {
        top: 100px;
        right: 20px;
    }
}