:root {
    /* 颜色变量 */
    --light-bg: #f0f4f8;
    --light-text: #102a43;
    --light-header: #1a365d;
    --light-card: #ffffff;
    --light-border: #cbd5e0;
    --light-accent: #3182ce;
    --light-hover: #edf2f7;
    
    --dark-bg: #0f172a;
    --dark-text: #e2e8f0;
    --dark-header: #1e293b;
    --dark-card: #1e293b;
    --dark-border: #334155;
    --dark-accent: #60a5fa;
    --dark-hover: #334155;
    
    /* 通用变量 */
    --spacing-sm: 4px;
    --spacing-md: 8px;
    --spacing-lg: 16px;
    --border-radius: 6px;
    --transition: all 0.3s ease;
}

/* 基础样式 */
body {
    font-family: 'Segoe UI', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
    margin: 0;
    padding: 0;
    transition: background-color 0.3s, color 0.3s;
    line-height: 1.3;
    background-color: var(--light-bg);
    color: var(--light-text);
}

/* 头部样式 */
header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 20px;
    background-color: var(--light-header);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
    flex-wrap: wrap;
    margin-top: 0; /* 确保没有顶部外边距 */
}

#logo {
    width: 40px;
    height: 40px;
    border-radius: 6px;
    object-fit: cover;
    transition: transform 0.3s;
    border: 1px solid rgba(255,255,255,0.1);
}

#logo:hover { transform: scale(1.05); }

header h1 {
    margin: 0 0 0 10px;
    flex-grow: 1;
    text-align: left;
    font-size: 1.5rem;
    color: #e2e8f0;
}

/* 搜索框样式 */
#searchForm {
    display: flex;
    align-items: center;
    justify-content: center;
    flex-grow: 1;
    order: 2;
    width: 100%;
    margin-top: 6px;
    position: relative;
}

#searchBox {
    padding: 8px 12px;
    border: 1px solid var(--light-accent);
    border-radius: 4px 0 0 4px;
    width: 160px;
    flex-grow: 1;
    font-size: 0.9rem;
    transition: var(--transition);
    background-color: #ffffff;
    color: var(--light-header);
}

#searchBox:focus {
    outline: none;
    border-color: #63b3ed;
    box-shadow: 0 0 0 2px rgba(66, 153, 225, 0.25);
}

#searchButton {
    padding: 8px 14px;
    border: none;
    border-radius: 0 4px 4px 0;
    background-color: var(--light-accent);
    color: white;
    cursor: pointer;
    transition: background-color 0.3s;
}

#searchButton:hover { background-color: #2b6cb0; }

/* 主题切换按钮 */
.theme-toggle {
    background: none;
    border: none;
    cursor: pointer;
    font-size: 20px;
    padding: 3px 6px;
    border-radius: 4px;
    transition: var(--transition);
    color: #e2e8f0;
}

.theme-toggle:hover { background-color: rgba(255, 255, 255, 0.1); }

/* 主内容区 */
main {
    padding: 20px;
    max-width: 1400px;
    margin: 0 auto;
}

/* 页脚样式 */
footer {
    text-align: center;
    padding: 12px 20px;
    background-color: var(--light-header);
    border-top: 1px solid #2c5282;
    margin-top: 20px;
    color: #a0aec0;
    font-size: 0.85rem;
}

footer p { margin: 3px 0; }

/* 卡片容器 */
.cards-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 15px;
}

/* 卡片样式 */
.card {
    border-radius: var(--border-radius);
    padding: 15px;
    transition: var(--transition);
    overflow: hidden;
    position: relative;
    border: 1px solid var(--light-border);
    background-color: var(--light-card);
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.05);
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background: linear-gradient(90deg, var(--light-accent), #63b3ed);
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(49, 130, 206, 0.1);
    border-color: #a0aec0;
}

.card h2 {
    margin: 0 0 10px 0;
    font-size: 1.1rem;
    color: var(--light-header);
    display: flex;
    align-items: center;
    gap: 6px;
    font-weight: 600;
    padding-bottom: 6px;
    border-bottom: 1px solid #e2e8f0;
}

/* 链接样式 */
.card a {
    display: block;
    padding: 6px 5px 6px 18px;
    margin-bottom: 4px;
    text-decoration: none;
    color: #2d3748;
    border-radius: 3px;
    transition: var(--transition);
    font-size: 0.9rem;
    position: relative;
}

.card a::before {
    content: '→';
    position: absolute;
    left: 5px;
    font-size: 10px;
    opacity: 0;
    transition: var(--transition);
    color: var(--light-accent);
}

.card a:hover {
    background-color: var(--light-hover);
    color: var(--light-accent);
    padding-left: 20px;
}

.card a:hover::before {
    opacity: 1;
    left: 7px;
}

/* 响应式布局 */
@media (min-width: 769px) {
    header {
        flex-direction: row;
        align-items: center;
    }

    #searchForm {
        order: 1;
        width: auto;
        margin: 0 12px;
        max-width: 400px;
    }

    #searchBox { width: 220px; }
}

@media (max-width: 768px) {
    header {
        flex-direction: column;
        align-items: center;
        padding: 10px 8px;
    }

    header h1 {
        margin: 6px 0;
        font-size: 1.3rem;
        text-align: center;
    }

    .cards-container {
        grid-template-columns: 1fr;
        gap: 12px;
    }
}

/* 暗黑主题 */
body.dark-theme {
    background-color: var(--dark-bg);
    color: var(--dark-text);
}

body.dark-theme header, 
body.dark-theme footer {
    background-color: var(--dark-header);
    color: #94a3b8;
    border-top-color: var(--dark-border);
}

body.dark-theme header h1 { color: #f1f5f9; }

body.dark-theme .card {
    background-color: var(--dark-card);
    border-color: var(--dark-border);
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
}

body.dark-theme .card::before {
    background: linear-gradient(90deg, var(--dark-accent), #93c5fd);
}

body.dark-theme .card h2 {
    color: #f1f5f9;
    border-bottom-color: var(--dark-border);
}

body.dark-theme .card a { color: var(--dark-text); }

body.dark-theme .card a:hover {
    background-color: var(--dark-hover);
    color: #93c5fd;
}

body.dark-theme .card a::before { color: #93c5fd; }

body.dark-theme #searchBox {
    background-color: var(--dark-border);
    border-color: #475569;
    color: #f1f5f9;
}

body.dark-theme #searchBox::placeholder { color: #94a3b8; }

/* 欢迎页面样式 */
#welcomeScreen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    background-color: var(--light-header);
    background-size: cover;
    background-position: center;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 100;
    transition: transform 0.5s ease-out;
}

.typing-container {
    text-align: center;
    color: white;
    font-size: 2rem;
    font-weight: 300;
    padding: 20px;
}

#cursor { animation: blink 1s step-end infinite; }

@keyframes blink {
    from, to { opacity: 1; }
    50% { opacity: 0; }
}

.scrollIndicator {
    position: absolute;
    bottom: 50px;
    color: white;
    text-align: center;
    animation: bounce 2s infinite;
}

.scrollIndicator p {
    margin-top: 10px;
    font-size: 0.9rem;
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% { transform: translateY(0); }
    40% { transform: translateY(-20px); }
    60% { transform: translateY(-10px); }
}

/* 主内容样式 */
#mainContent {
    position: relative;
    z-index: 10;
    min-height: 100vh;
    /* 移除或减小顶部内边距 */
    padding-top: 0;
    transform: translateY(100vh);
    transition: transform 0.5s ease-out;
}

#mainContent.visible { transform: translateY(0); }

body.dark-theme #welcomeScreen { background-color: var(--dark-header); }

/* Font Awesome 图标支持 */
.fas {
    font-family: "Font Awesome 5 Free";
    font-weight: 900;
}