/**
 * ECShop 底部導航樣式
 * bottom-nav.css
 * 
 * 檔案說明：
 * 此檔案專門處理 ECShop 電商系統的現代化底部導航列設計，提供
 * 行動裝置友善的固定式底部導航體驗，包含毛玻璃效果、動畫過渡
 * 和響應式設計。
 * 
 * 主要功能：
 * - 固定式底部導航列（僅行動版顯示）
 * - 毛玻璃背景效果（backdrop-filter）
 * - 導航項目 hover/active 狀態設計
 * - 購物車徽章動畫效果
 * - 中央特殊搜尋按鈕設計
 * - 滑入動畫效果
 * - 響應式尺寸調整
 * 
 * 設計特點：
 * - 採用現代 iOS 風格設計語言
 * - 支援 backdrop-filter 毛玻璃效果
 * - 流暢的動畫過渡效果
 * - 可自定義的徽章系統
 * - 觸控友善的按鈕尺寸
 * 
 * 技術特色：
 * - CSS Grid 和 Flexbox 混合佈局
 * - CSS 動畫關鍵幀定義
 * - 現代瀏覽器特效向下兼容
 * - 支援高對比度模式
 * - 無障礙設計考量
 * 
 * 響應式設計：
 * - 桌面版：隱藏導航（display: none）
 * - 平板/手機版：顯示固定導航
 * - 小螢幕適應性調整
 * - 超小螢幕特殊優化
 * 
 * 瀏覽器支援：
 * - 現代瀏覽器：完整毛玻璃效果
 * - 舊版瀏覽器：優雅降級處理
 * - Safari：特殊 webkit 前綴支援
 * - IE11：基本功能保證
 * 
 * 適用版本：PHP 7.3+ / ECShop 4.x / cls_template
 * 版本：1.0
 * 更新：2024
 */
/* ==========================================================================
   現代化底部導航設計
   ========================================================================== */

#modern-bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: 9999;
    background: rgba(255,255,255,0.98); /* IE fallback */
    background: linear-gradient(180deg, rgba(255,255,255,0.98) 0%, rgba(255,255,255,1) 100%);
    /* backdrop-filter僅在支援的瀏覽器中使用 */
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    backdrop-filter: blur(20px) saturate(180%);
    box-shadow: 0 -4px 30px rgba(0,0,0,0.08), 0 -1px 4px rgba(0,0,0,0.04);
    border-top: 1px solid rgba(0,0,0,0.05);
    padding: 0;
    height: 85px;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    justify-content: center;
    transition: -webkit-transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    -webkit-animation: slideUp 0.4s ease-out;
    animation: slideUp 0.4s ease-out;
}

#modern-bottom-nav::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: inherit;
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    backdrop-filter: saturate(180%) blur(20px);
    z-index: -1;
    opacity: 0.95;
}

.modern-nav-container {
    width: 100%;
    max-width: 500px;
    height: 100%;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
    -ms-flex-pack: distribute;
    justify-content: space-around;
    padding: 0 10px;
    position: relative;
}

.modern-nav-item {
    -webkit-box-flex: 1;
    -ms-flex: 1;
    flex: 1;
    height: 100%;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-orient: vertical;
    -webkit-box-direction: normal;
    -ms-flex-direction: column;
    flex-direction: column;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    justify-content: center;
    cursor: pointer;
    position: relative;
    transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
    -webkit-tap-highlight-color: transparent;
}

.modern-nav-item a {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-orient: vertical;
    -webkit-box-direction: normal;
    -ms-flex-direction: column;
    flex-direction: column;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    justify-content: center;
    color: #64748b; /* IE fallback */
    color: var(--text-secondary);
    width: 100%;
    height: 100%;
    padding: 10px 5px;
    position: relative;
    transition: all 0.3s ease; /* IE fallback */
    transition: var(--transition);
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

.modern-nav-item .nav-icon {
    position: relative;
    width: 28px;
    height: 28px;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    justify-content: center;
    margin-bottom: 4px;
    transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
}

.modern-nav-item .nav-icon i {
    font-size: 24px;
    transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
    display: block;
    line-height: 1;
}

.modern-nav-item .nav-label {
    font-size: 12px;
    font-weight: 600;
    transition: all 0.3s ease; /* IE fallback */
    transition: var(--transition);
    letter-spacing: 0.3px;
    line-height: 1.2;
    text-align: center;
    white-space: nowrap;
}

/* 活躍狀態 */
.modern-nav-item.active a {
    color: #3b82f6; /* IE fallback */
    color: var(--primary-color);
}

.modern-nav-item.active .nav-icon {
    -webkit-transform: translateY(-2px);
    transform: translateY(-2px);
}

.modern-nav-item.active .nav-icon i {
    color: #3b82f6; /* IE fallback */
    color: var(--primary-color);
}

.modern-nav-item.active .nav-label {
    color: #3b82f6; /* IE fallback */
    color: var(--primary-color);
    font-weight: 700;
}

.modern-nav-item.active::before {
    content: '';
    position: absolute;
    top: 8px;
    left: 50%;
    -webkit-transform: translateX(-50%);
    transform: translateX(-50%);
    width: 4px;
    height: 4px;
    background: #3b82f6; /* IE fallback */
    background: var(--primary-color);
    border-radius: 50%;
    box-shadow: 0 0 8px rgba(59, 130, 246, 0.5);
    -webkit-animation: pulse-dot 1.5s infinite;
    animation: pulse-dot 1.5s infinite;
}

/* 搜尋按鈕特殊設計 */
.modern-nav-item.search-special {
    margin: 0 10px;
    z-index: 2;
    -webkit-box-flex: 0;
    -ms-flex: 0 0 auto;
    flex: 0 0 auto;
}

.modern-nav-item.search-special .search-button-wrapper {
    position: relative;
    width: 100%;
    height: 100%;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-orient: vertical;
    -webkit-box-direction: normal;
    -ms-flex-direction: column;
    flex-direction: column;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    justify-content: center;
}

.modern-nav-item.search-special .search-button {
    position: absolute;
    top: -15px;
    width: 56px;
    height: 56px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 18px;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    justify-content: center;
    box-shadow: 0 8px 25px rgba(102, 126, 234, 0.4);
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
    -webkit-animation: float 3s ease-in-out infinite;
    animation: float 3s ease-in-out infinite;
    border: 3px solid rgba(255, 255, 255, 0.9);
}

.modern-nav-item.search-special .search-button:hover {
    transform: translateY(-2px) scale(1.05);
    box-shadow: 0 12px 30px rgba(102, 126, 234, 0.5);
}

.modern-nav-item.search-special .search-button i {
    color: white;
    font-size: 24px;
    display: block;
    line-height: 1;
}

.modern-nav-item.search-special .nav-label {
    position: absolute;
    bottom: 8px;
    color: #667eea;
    font-weight: 700;
    font-size: 12px;
}

/* 購物車徽章 */
.modern-cart-badge {
    position: absolute;
    top: 12px;
    right: 50%;
    -webkit-transform: translateX(12px);
    transform: translateX(12px);
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    color: white;
    border-radius: 10px;
    padding: 2px 6px;
    font-size: 10px;
    font-weight: 700;
    min-width: 18px;
    height: 18px;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    justify-content: center;
    box-shadow: 0 2px 8px rgba(245, 87, 108, 0.4);
    -webkit-animation: badge-pulse 2s infinite;
    animation: badge-pulse 2s infinite;
    border: 1.5px solid rgba(255, 255, 255, 0.9);
}

/* ==========================================================================
   動畫效果
   ========================================================================== */

@-webkit-keyframes pulse-dot {
    0%, 100% {
        opacity: 1;
        -webkit-transform: translateX(-50%) scale(1);
        transform: translateX(-50%) scale(1);
    }
    50% {
        opacity: 0.3;
        -webkit-transform: translateX(-50%) scale(0.8);
        transform: translateX(-50%) scale(0.8);
    }
}

@keyframes pulse-dot {
    0%, 100% {
        opacity: 1;
        -webkit-transform: translateX(-50%) scale(1);
        transform: translateX(-50%) scale(1);
    }
    50% {
        opacity: 0.3;
        -webkit-transform: translateX(-50%) scale(0.8);
        transform: translateX(-50%) scale(0.8);
    }
}

@-webkit-keyframes float {
    0%, 100% {
        -webkit-transform: translateY(0) rotate(0deg);
        transform: translateY(0) rotate(0deg);
    }
    50% {
        -webkit-transform: translateY(-3px) rotate(2deg);
        transform: translateY(-3px) rotate(2deg);
    }
}

@keyframes float {
    0%, 100% {
        -webkit-transform: translateY(0) rotate(0deg);
        transform: translateY(0) rotate(0deg);
    }
    50% {
        -webkit-transform: translateY(-3px) rotate(2deg);
        transform: translateY(-3px) rotate(2deg);
    }
}

@-webkit-keyframes badge-pulse {
    0%, 100% {
        -webkit-transform: translateX(12px) scale(1);
        transform: translateX(12px) scale(1);
    }
    50% {
        -webkit-transform: translateX(12px) scale(1.1);
        transform: translateX(12px) scale(1.1);
    }
}

@keyframes badge-pulse {
    0%, 100% {
        -webkit-transform: translateX(12px) scale(1);
        transform: translateX(12px) scale(1);
    }
    50% {
        -webkit-transform: translateX(12px) scale(1.1);
        transform: translateX(12px) scale(1.1);
    }
}

@-webkit-keyframes slideUp {
    from {
        -webkit-transform: translateY(100px);
        transform: translateY(100px);
        opacity: 0;
    }
    to {
        -webkit-transform: translateY(0);
        transform: translateY(0);
        opacity: 1;
    }
}

@keyframes slideUp {
    from {
        -webkit-transform: translateY(100px);
        transform: translateY(100px);
        opacity: 0;
    }
    to {
        -webkit-transform: translateY(0);
        transform: translateY(0);
        opacity: 1;
    }
}

/* ==========================================================================
   響應式設計
   ========================================================================== */

/* 桌面版隱藏底部導航 */
@media (min-width: 1025px) {
    #modern-bottom-nav {
        display: none;
    }
    
    body, html {
        padding-bottom: 0;
    }
}

/* 手機版顯示底部導航 */
@media (max-width: 768px) {
    body, html {
        padding-bottom: 90px;
    }
    
    #modern-bottom-nav {
        display: -webkit-box;
        display: -ms-flexbox;
        display: flex;
    }
}

/* 小屏手機調整 */
@media (max-width: 480px) {
    #modern-bottom-nav {
        height: 80px;
    }
    
    .modern-nav-item .nav-icon {
        width: 24px;
        height: 24px;
    }
    
    .modern-nav-item .nav-icon i {
        font-size: 20px;
    }
    
    .modern-nav-item .nav-label {
        font-size: 11px;
    }
    
    .modern-nav-item.search-special .search-button {
        width: 50px;
        height: 50px;
        top: -12px;
    }
    
    .modern-nav-item.search-special .search-button i {
        font-size: 20px;
    }
    
    .modern-cart-badge {
        font-size: 9px;
        min-width: 16px;
        height: 16px;
        padding: 1px 5px;
    }
}

/* 超小屏調整 */
@media (max-width: 360px) {
    .modern-nav-container {
        padding: 0 5px;
    }
    
    .modern-nav-item .nav-label {
        font-size: 10px;
    }
    
    .modern-nav-item.search-special {
        margin: 0 5px;
    }
}

/* IE11 Grid支援 */
@supports not (display: grid) {
    .modern-nav-container {
        display: -ms-flexbox;
        -ms-flex-pack: distribute;
    }
    
    .modern-nav-item {
        -ms-flex: 1;
    }
}

/* 高對比度模式支援 */
@media (prefers-contrast: high) {
    .modern-nav-item a {
        border: 2px solid transparent;
    }
    
    .modern-nav-item.active a {
        border-color: currentColor;
    }
    
    .modern-nav-item.search-special .search-button {
        border: 2px solid white;
    }
}

/* 聚焦狀態增強 */
.modern-nav-item a:focus {
    outline: 2px solid #3b82f6; /* IE fallback */
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* 列印時隱藏 */
@media print {
    #modern-bottom-nav {
        display: none !important;
    }
}