/* ==========================================================================
   nav-theme.css  主导航 dropdown + 主题配色面板
   - 全页面共享（所有前台页面顶部 navbar 都用这套 dropdown）
   - 不依赖 layui.dropdown 模块（项目不引入 layui.dropdown 时也能用）
   ========================================================================== */

/* ============== 主导航按钮（替代原横排 .nav-links） ============== */

.nav-main-btn {
    background: var(--nav-tag-bg);
    color: var(--nav-card-text);
    border: none;
    cursor: pointer;
    padding: 9px 16px;
    border-radius: 22px;
    font-size: 15px;
    font-weight: 500;
    transition: all .3s;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    white-space: nowrap;
    font-family: inherit;
}
.nav-main-btn:hover { background: var(--nav-primary); color: #fff; }
.nav-main-btn .caret { font-size: 11px; opacity: .75; transition: transform .3s; display: inline-block; }
.nav-main-btn[aria-expanded="true"] { background: var(--nav-primary); color: #fff; }
.nav-main-btn[aria-expanded="true"] .caret { transform: rotate(180deg); }

/* ============== 主导航下拉面板 ============== */

.main-nav-panel {
    position: absolute;
    z-index: 999999;
    background: var(--nav-card);
    border: 1px solid var(--nav-border);
    border-radius: 12px;
    box-shadow: 0 8px 30px rgba(0,0,0,.18);
    min-width: 200px;
    padding: 6px 0;
    display: none;
    margin: 0;
}
.main-nav-panel.show { display: block; animation: navFadeIn .15s ease-out; }
.main-nav-panel ul { list-style: none; margin: 0; padding: 0; }
.main-nav-panel li a {
    display: block;
    padding: 10px 18px;
    color: var(--nav-card-text);
    text-decoration: none;
    font-size: 14px;
    transition: background .15s, color .15s;
    white-space: nowrap;
}
.main-nav-panel li a:hover, .main-nav-panel li.active a {
    background: var(--nav-primary);
    color: #fff;
}

/* ============== 主题配色面板 ============== */

.theme-popover {
    position: absolute;
    z-index: 999999;
    display: none;
}
.theme-popover.show { display: block; animation: navFadeIn .15s ease-out; }
.theme-panel { padding: 14px 16px; min-width: 260px; max-width: 320px; color: var(--nav-card-text); background: var(--nav-card); border: 1px solid var(--nav-border); border-radius: 12px; box-shadow: 0 8px 30px rgba(0,0,0,.18); }
.theme-panel h4 {
    font-size: 12px; color: var(--nav-muted); margin: 0 0 8px; font-weight: 600;
    letter-spacing: .5px; text-transform: uppercase;
}
.theme-panel .group + .group { margin-top: 14px; padding-top: 12px; border-top: 1px dashed var(--nav-border); }
.theme-panel .seg { display: flex; gap: 6px; flex-wrap: wrap; }
.theme-panel .seg-btn {
    cursor: pointer; border: 2px solid transparent; padding: 6px 12px;
    border-radius: 18px; background: var(--nav-tag-bg); color: var(--nav-card-text);
    font-size: 13px; transition: all .2s; font-family: inherit;
}
.theme-panel .seg-btn:hover { filter: brightness(1.05); }
.theme-panel .seg-btn.active {
    border-color: var(--nav-primary); background: var(--nav-primary); color: #fff;
}
.theme-panel .swatch {
    cursor: pointer; border: 2px solid transparent; padding: 0;
    width: 28px; height: 28px; border-radius: 50%; display: inline-block;
    background-clip: padding-box; transition: transform .2s;
    box-shadow: 0 1px 4px rgba(0,0,0,.15);
}
.theme-panel .swatch:hover { transform: scale(1.15); }
.theme-panel .swatch.active {
    border-color: #fff; outline: 2px solid var(--nav-primary); outline-offset: 1px;
}

/* 触发按钮激活态 */
.icon-btn[aria-expanded="true"] { background: var(--nav-primary); color: #fff; transform: translateY(-2px); }

/* 主题面板底部「恢复默认」按钮 */
.theme-panel .reset-row {
    margin-top: 14px; padding-top: 12px;
    border-top: 1px dashed var(--nav-border);
    text-align: right;
}
.theme-panel .reset-btn {
    cursor: pointer; border: none; padding: 6px 14px;
    border-radius: 16px; background: transparent;
    color: var(--nav-muted); font-size: 12px; font-family: inherit;
    transition: color .2s, background .2s;
}
.theme-panel .reset-btn:hover { color: var(--nav-primary); background: var(--nav-tag-bg); }

/* ============== 背景图片遮罩层（nav-theme.js img: 模式） ==============
 * body.nav-bg-img 建立层叠上下文，::before 半透明遮罩盖在背景图之上、
 * 页面内容之下，保证卡片文字可读；强度由 --nav-bg-mask（后台可配 0-90%）控制。 */
body.nav-bg-img { position: relative; z-index: 0; }
body.nav-bg-img::before {
    content: '';
    position: fixed;
    inset: 0;
    z-index: -1;
    pointer-events: none;
    background: rgba(255, 255, 255, var(--nav-bg-mask, .35));
    transition: background .3s;
}
[data-theme="dark"] body.nav-bg-img::before {
    /* 暗色模式下遮罩改为压暗，而非提亮 */
    background: rgba(15, 17, 26, calc(var(--nav-bg-mask, .35) + .1));
}

/* ============== 面板：自定义图片背景输入行 ============== */

.theme-panel .bg-url-row { display: flex; gap: 6px; margin-top: 8px; }
.theme-panel .bg-url-row input {
    flex: 1; min-width: 0; padding: 6px 10px; font-size: 12px; font-family: inherit;
    border: 1px solid var(--nav-border); border-radius: 8px; outline: none;
    background: var(--nav-tag-bg); color: var(--nav-card-text); transition: border-color .2s;
}
.theme-panel .bg-url-row input:focus { border-color: var(--nav-primary); }
.theme-panel .bg-url-row .bg-apply-btn {
    cursor: pointer; flex-shrink: 0; padding: 6px 12px; font-size: 12px; font-family: inherit;
    border: none; border-radius: 8px; background: var(--nav-primary); color: #fff;
    transition: filter .2s;
}
.theme-panel .bg-url-row .bg-apply-btn:hover { filter: brightness(1.1); }

/* ============== 下拉面板出场动画 ============== */

@keyframes navFadeIn {
    from { opacity: 0; transform: translateY(-4px); }
    to   { opacity: 1; transform: translateY(0); }
}

/* ============== 小屏响应式 ============== */

@media (max-width: 768px) {
    .nav-main-btn { font-size: 14px; padding: 8px 14px; }
}
@media (max-width: 480px) {
    .nav-main-btn { font-size: 13px; padding: 7px 12px; max-width: 180px; overflow: hidden; text-overflow: ellipsis; }
    /* 小屏：面板宽度保护（不超出可视区，按钮对齐右沿） */
    .main-nav-panel, .theme-popover .theme-panel { max-width: calc(100vw - 16px); right: 8px !important; left: 8px !important; width: auto !important; }
}