:root {
        --primary: #007AFF;
        --bg-main: #F0F9FF;
        --text-dark: #1D1D1F;
        --text-gray: #666;
        --text-light: #999;
        --white: #FFF;
    }
    * { -webkit-tap-highlight-color: transparent; box-sizing: border-box; outline: none; }
    body { margin: 0 auto; max-width: 640px; background: var(--bg-main); font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Helvetica Neue", Arial, sans-serif; color: var(--text-dark); padding-bottom: 80px; line-height: 1.5; }
    a { text-decoration: none; color: inherit; }
    ::-webkit-scrollbar { width: 0; background: transparent; }
    .course-nav { position: sticky; top: 0; width: 100%; display: flex; justify-content: center; gap: 12px; padding: 12px 16px; z-index: 100; backdrop-filter: blur(12px); }
    .course-nav a { position: relative; flex: 1; padding: 8px 0; border-radius: 16px; border: 2px solid transparent; transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1); cursor: pointer; }
    .nav-title { display: flex; align-items: center; justify-content: center; font-size: 16px; font-weight: 600; color: #98989E; line-height: 1; transition: transform 0.2s ease; }
    .nav-img { width: 28px; height: 28px; margin-right: 8px; object-fit: contain; }
    .course-nav a.nav-active { background-image: linear-gradient(var(--white), var(--white)), linear-gradient(135deg, var(--primary), #5856D6); background-origin: padding-box, border-box; background-clip: padding-box, border-box; box-shadow: 0 4px 16px rgba(0, 122, 255, 0.15); }
    .course-nav a.nav-active .nav-title { color: var(--primary); transform: scale(1.02); }
    .course-nav a:active .nav-title { transform: scale(0.95); opacity: 0.7; }
    #search-container, #search-container-2 { position: relative; display: flex; justify-content: center; margin: 16px 0; }
    #search-container > div, #search-container-2 > div { position: relative; width: 100%; max-width: 92%; }
    input[type="text"] { width: 100%; padding: 10px 40px 10px 35px; border: 1px solid #eee; background: var(--white); border-radius: 8px; box-shadow: 0 4px 12px rgba(0,0,0,0.04); font-size: 14px; color: #333; -webkit-appearance: none; transition: border-color 0.2s; }
    input[type="text"]:focus { border-color: var(--primary); }
    input::placeholder { color: #ccc; }
    .search-icon, #clear-button, #clear-button-2 { position: absolute; top: 50%; transform: translateY(-50%); z-index: 5; }
    .search-icon { left: 14px; color: #aaa; pointer-events: none; font-size: 14px; }
    #clear-button, #clear-button-2 { right: 12px; background: transparent; border: none; color: var(--text-light); padding: 4px; cursor: pointer; z-index: 10; display: flex; align-items: center; justify-content: center; }
    #clear-button:active, #clear-button-2:active { opacity: 0.6; transform: translateY(-50%) scale(0.9); }

    .fd-tutorial, .fd-problem, .fd-code { padding: 0 16px 16px; }
    .fd-problem, .fd-code { display: none; }
    .fd-tutorial { display: block; }
    
    h3 { position: relative; margin: 32px 0 16px; font-size: 16px; font-weight: 600; color: var(--text-gray); line-height: 1; display: flex; align-items: center; justify-content: center; }
    h3::after { content: "更新"; margin-left: 10px; font-size: 10px; font-weight: 800; color: var(--primary); background: rgba(0, 122, 255, 0.12); padding: 3px 6px; border-radius: 6px; letter-spacing: 0.5px; }

    .app { display: flex; align-items: flex-start; background: var(--white); margin: 10px; padding: 10px; border-radius: 12px; box-shadow: 0 2px 6px #d0d0d0; position: relative; }
    .app:active { background: #f9f9f9; }
    .app img { width: 55px; height: 55px; margin-right: 12px; border-radius: 12px; flex-shrink: 0; background: #f0f0f0; }
    .app-content { flex: 1; display: flex; flex-direction: column; justify-content: center; min-height: 55px; }
    .app h2 { margin: 0 0 6px; font-size: 15px; font-weight: 600; color: #333; line-height: 1.2; }
    .app h2 span { color: #F00; font-size: 14px; font-weight: 400; margin-left: 5px; }
    .app p { margin: 0; font-size: 12px; color: var(--text-gray); line-height: 1.5; }
    .app p span { display: inline-block; padding: 1px 6px; border-radius: 4px; font-size: 10px; margin-right: 4px; border: 1px solid #646566; }
    .app p c { display: block; color: var(--text-light); margin-top: 4px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; max-width: 240px; }

    .rank-number, .new-tag { position: absolute; top: 0; left: 0; z-index: 10; border-radius: 12px 0 10px 0; min-width: 20px; height: 18px; line-height: 18px; padding: 0 5px; font-size: 10px; font-weight: 700; color: var(--white); text-align: center; box-shadow: 1px 1px 1px rgba(0,0,0,0.15); }
    .rank-number { background: #999; }
    .top-1 .rank-number { background: linear-gradient(135deg, #FF3B30, #FF9500); z-index: 12; font-size: 11px; }
    .top-2 .rank-number { background: linear-gradient(135deg, #FF9500, #FFCC00); z-index: 11; }
    .top-3 .rank-number { background: linear-gradient(135deg, #FFCC00, #FFDB4D); color: #947600; z-index: 11; }
    .top-4 .rank-number { background: #1989fa; }
    .top-5 .rank-number { background: #e40fe7; }
    .top-10 .rank-number { min-width: 24px; }
    .new-tag { background: #34C759; }
    .floating-toolbar { position: fixed; right: 16px; bottom: 100px; z-index: 900; display: flex; flex-direction: column; gap: 12px; align-items: flex-end; }
    .floating-btn { width: 44px; height: 44px; border-radius: 50%; border: none; display: flex; align-items: center; justify-content: center; cursor: pointer; box-shadow: 0 4px 12px rgba(0,0,0,0.15); transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1); padding: 0; }
    .floating-btn:active { transform: scale(0.9); }
    .gradient-btn { background: linear-gradient(135deg, #FF9500, #FF3B30); animation: pulse-orange 2s infinite; }
    .dark-btn { background: rgba(0,0,0,0.6); backdrop-filter: blur(4px); }
    .float-icon { width: 32px; height: 32px; object-fit: contain; pointer-events: none; }

    .menu-popover { position: absolute; bottom: 60px; right: 0; width: 180px; background: var(--white); border-radius: 16px; box-shadow: 0 8px 24px rgba(0,0,0,0.12); padding: 16px; opacity: 0; visibility: hidden; transform: translateY(20px) scale(0.9); transition: all 0.3s; transform-origin: bottom right; z-index: 901; }
    .menu-popover.active { opacity: 1; visibility: visible; transform: translateY(0) scale(1); }
    .popover-item { display: flex; align-items: center; padding: 8px 12px; background: #F5F7FA; border-radius: 12px; font-size: 14px; font-weight: 500; margin-top: 8px; }
    .popover-item:active { background: #ECEEF2; }
    .popover-item img { width: 20px; height: 20px; margin-right: 8px; }
    @keyframes pulse-orange { 0%, 100% { box-shadow: 0 4px 12px rgba(255,59,48,0.3); } 50% { box-shadow: 0 4px 18px rgba(255,59,48,0.5); } }
    
    .nav-tip { position: absolute; top: -30px; left: 50%; transform: translateX(-50%); background: var(--primary); color: var(--white); font-size: 11px; padding: 5px 10px; border-radius: 8px; white-space: nowrap; transition: all 0.3s; z-index: 101; pointer-events: none; animation: tip-bounce 1.5s infinite ease-in-out; }
    .nav-tip::after { content: ''; position: absolute; bottom: -5px; left: 50%; transform: translateX(-50%); border: 5px solid transparent; border-top-color: var(--primary); }
    .nav-tip.tip-hidden { opacity: 0; transform: translate(-50%, 10px); }
    @keyframes tip-bounce { 0%, 100% { transform: translate(-50%, 0); } 50% { transform: translate(-50%, -5px); } }

    .notice-bar { background: #FFFBE6; color: #FF9500; height: 36px; display: flex; align-items: center; font-size: 13px; padding: 0 12px; overflow: hidden; position: relative; border-bottom: 1px solid rgba(255,149,0,0.1); }
    .notice-title { display: flex; align-items: center; font-weight: 700; white-space: nowrap; z-index: 2; background: #FFFBE6; padding-right: 8px; box-shadow: 10px 0 15px #FFFBE6; }
    .notice-scroller { flex: 1; overflow: hidden; height: 100%; display: flex; align-items: center; }
    .notice-text { white-space: nowrap; animation: marquee-scroll 15s linear infinite; padding-left: 100%; }
    @keyframes marquee-scroll { 100% { transform: translate(-100%); margin-left: -200px; } }

    .layui-m-layer0 .layui-m-layerchild { width: 85% !important; max-width: 640px !important; border-radius: 16px !important; }
    .layui-layer-msg { background: rgba(0,0,0,0.8) !important; border-radius: 8px !important; color: var(--white) !important; }
    .circle-copy, .circle-load, .circle-done { stroke-dasharray: 63; stroke-dashoffset: 63; }
    .tick-copy, .tick-load, .tick-done { stroke-dasharray: 20; stroke-dashoffset: 20; }
    @keyframes circle { to { stroke-dashoffset: 0; } }
    @keyframes tick { to { stroke-dashoffset: 0; } }
    .fd-video-img{width: 100%; display: block;}
    body { 
        background-color: #F4F0EA !important; 
        background-image: 
            linear-gradient(#E8E4DD 1px, transparent 1px),
            linear-gradient(90deg, #E8E4DD 1px, transparent 1px) !important;
        background-size: 20px 20px !important; /* 经典方格纸背景 */
        color: #000 !important; 
        font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Helvetica Neue", Arial, sans-serif !important;
    }

    .course-nav {
        background: transparent !important;
        /*backdrop-filter: none !important;*/
        border: none !important;
        box-shadow: none !important;
        padding: 8px 16px 8px 16px !important;
        gap: 16px !important;
    }
    .course-nav a { 
        background: #FFF !important;
        border: 3px solid #000 !important; 
        border-radius: 8px !important; 
        box-shadow: 4px 4px 0px #000 !important; 
        transition: transform 0.1s, box-shadow 0.1s !important; 
    }
    .nav-title { font-weight: 800 !important; color: #000 !important; }
    
    .course-nav a.nav-active {
        background: #FF3B30 !important; 
        transform: translate(4px, 4px) !important; 
        box-shadow: 0px 0px 0px #000 !important; 
    }
    .course-nav a.nav-active .nav-title { color: #FFF !important; }

    #search-container input[type="text"], #search-container-2 input[type="text"] {
        background: #FFF !important;
        border: 3px solid #000 !important;
        color: #000 !important;
        border-radius: 12px !important;
        box-shadow: 6px 6px 0px rgba(0,0,0,1) !important;
        font-weight: 600 !important;
        transition: all 0.1s !important;
    }
    #search-container input[type="text"]:focus {
        background: #F4F0EA !important;
        transform: translate(2px, 2px) !important;
        box-shadow: 4px 4px 0px rgba(0,0,0,1) !important;
    }
    .search-icon, #clear-button { color: #000 !important; font-weight: 800 !important; }

    .app {
        background: #FFF !important;
        border-radius: 12px !important;
        margin: 0 16px 24px 16px !important;
        border: 3px solid #000 !important;
        box-shadow: 8px 8px 0px #000 !important; 
        transition: all 0.1s cubic-bezier(0.4, 0, 0.2, 1) !important;
    }

    .app:active { 
        transform: translate(8px, 8px) !important; 
        box-shadow: 0px 0px 0px #000 !important; 
        background: #F8F8F8 !important;
    }
    

    .app img {
        border-radius: 8px !important;
        border: 2px solid #000 !important;
        background: #FFF !important;
    }


    .app h2 { font-size: 17px !important; font-weight: 900 !important; color: #000 !important; letter-spacing: -0.5px !important; }
    
    .app h2 span {
        display: inline-block !important;
        background: #FAFA00 !important; 
        color: #000 !important; 
        padding: 4px 10px !important;
        font-size: 13px !important;
        font-weight: 900 !important;
        border-radius: 20px !important; 
        margin-left: 6px !important;
        border: 2px solid #000 !important;
        box-shadow: 2px 2px 0px #000 !important;
        vertical-align: middle !important;
        transform: translateY(-2px) !important;
    }

    .app p span {
        background: #00C2FF !important; 
        border: 2px solid #000 !important;
        color: #FFF !important;
        font-weight: 800 !important;
        border-radius: 6px !important;
        padding: 2px 6px !important;
        box-shadow: 1px 1px 0 #000 !important;
    }
    .app p c { color: #666 !important; font-weight: 600 !important; margin-top: 10px !important; border-top: 2px dashed #000 !important; padding-top: 6px !important; }

    .rank-number, .new-tag {
        border-radius: 8px !important; 
        top: -10px !important;
        left: -10px !important;
        padding: 0 10px !important;
        font-weight: 900 !important;
        font-size: 12px !important;
        border: 1px solid #000 !important;
        box-shadow: 3px 3px 0 #000 !important;
        transform: rotate(-5deg) !important; 
    }
    .top-1 .rank-number { background: #FF3B30 !important; color: #FFF !important; }
    .top-2 .rank-number { background: #FF9500 !important; color: #000 !important; }
    .top-3 .rank-number { background: #FAFA00 !important; color: #000 !important; }
    .default-rank .rank-number { background: #E5E5EA !important; color: #000 !important; }
    .new-tag { background: #00FF00 !important; color: #000 !important; }

    h3 { color: #000 !important;/* font-weight: 900 !important; font-size: 20px !important; border-bottom: 4px solid #000 !important; padding-bottom: 8px !important; display: inline-block !important; margin-left: 50% !important; transform: translateX(-50%) !important;*/ }
    h3::after { display: none !important; }
    
    .floating-btn { border: 3px solid #000 !important; box-shadow: 4px 4px 0 #000 !important; border-radius: 12px !important; }
    .gradient-btn { background: #FF3B30 !important; animation: none !important; }
    .floating-btn:active { transform: translate(4px, 4px) !important; box-shadow: 0 0 0 #000 !important; }

    .layui-m-layer0 .layui-m-layerchild {
        border: 4px solid #000 !important;
        border-radius: 12px !important;
        box-shadow: 12px 12px 0px #000 !important;
        background-color: #FFF !important;
    }
    
    .layui-m-layerbtn {
        background-color: #FFF !important;
        border-top: 4px solid #000 !important;
        height: 60px !important;
        line-height: 60px !important;
    }
    
    .layui-m-layerbtn span[yes] {
        color: #000 !important;
        font-weight: 900 !important;
        font-size: 18px !important;
        background: #FAFA00 !important; 
        transition: background 0.1s !important;
    }
    .layui-m-layerbtn span[yes]:active {
        background: #FF3B30 !important; 
        color: #FFF !important;
    }

    .layui-layer-msg {
        border: 3px solid #000 !important;
        background: #FFF !important;
        color: #000 !important;
        font-weight: 900 !important;
        box-shadow: 6px 6px 0px #000 !important;
        border-radius: 8px !important;
    }
    
    .notice-bar {
        /*background: #00C2FF !important;  荧光蓝底色 */
        color: #000 !important;
        border-bottom: 4px solid #000 !important;
        height: 40px !important;
        box-shadow: 0 4px 0px rgba(0,0,0,1) !important;
        margin-bottom: 12px !important; 
    }
    .notice-title {
        background: #FAFA00 !important; 
        color: #000 !important;
        font-weight: 900 !important;
        border-right: 4px solid #000 !important; 
        padding: 0 12px !important;
        box-shadow: none !important; 
        z-index: 10 !important;
    }
    .notice-text { font-weight: 900 !important; letter-spacing: 1px !important; }

    .menu-popover {
        background: #FFF !important;
        border: 4px solid #000 !important;
        border-radius: 12px !important;
        box-shadow: 10px 10px 0px #000 !important; 
        padding: 16px !important;
        transition: transform 0.2s cubic-bezier(0.34, 1.56, 0.64, 1), opacity 0.2s !important;
    }
    
    .popover-title {
        font-weight: 900 !important;
        font-size: 16px !important;
        color: #000 !important;
        border-bottom: 4px dashed #000 !important; 
        padding-bottom: 12px !important;
        margin-bottom: 12px !important;
    }
    
    .popover-item {
        background: #F4F0EA !important; 
        border: 3px solid #000 !important;
        border-radius: 8px !important;
        box-shadow: 4px 4px 0px #000 !important;
        font-weight: 800 !important;
        color: #000 !important;
        margin-bottom: 12px !important;
        transition: all 0.1s !important; 
    }
    .popover-item:last-child { margin-bottom: 0 !important; }
    

    .popover-item:active {
        transform: translate(4px, 4px) !important;
        box-shadow: 0px 0px 0px #000 !important;
        background: #00FF00 !important; 
        color: #000 !important;
    }
    
    .popover-item img {
        filter: grayscale(100%) contrast(200%) !important; 
    }
    
    .skeleton-card {
        pointer-events: none !important; 
        background: #FFF !important;
    }
    
    .sk-img {
        width: 60px; height: 60px; 
        margin-right: 14px; 
        border: 2px solid #000; 
        border-radius: 8px;
    }
    .sk-title {
        height: 18px; width: 60%; 
        border: 2px solid #000;
        margin-bottom: 12px;
    }
    .sk-tags { display: flex; gap: 6px; }
    .sk-tag { width: 40px; height: 18px; border: 2px solid #000; }
    .sk-desc {
        height: 12px; width: 85%; 
        border: 2px solid #000;
        margin-top: 14px;
    }

    .sk-img, .sk-title, .sk-tag, .sk-desc {
        background: #000;
        animation: brutal-blink 0.6s steps(2, end) infinite;
    }

    .sk-title { animation-delay: 0.1s; }
    .sk-tags { animation-delay: 0.2s; }
    .sk-desc { animation-delay: 0.3s; }

    @keyframes brutal-blink {
        0% { background: #000; border-color: #000; }
        50% { background: #F4F0EA; border-color: #000; } 
        100% { background: #000; border-color: #000; }
    }