/* Global Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    /* 确保滚动条始终可见，防止内容变化时滚动条出现/消失导致页面宽度变化 */
    overflow-y: scroll;
}

body {
    font-family: var(--font-primary);
    color: var(--color-text);
    background-color: var(--color-bg);
    line-height: var(--leading-normal);
    overflow-x: hidden;
    overflow-y: visible; /* 禁止body创建内部滚动条，只使用html的滚动条 */
    height: auto; /* 确保body高度跟随内容，不创建独立的滚动上下文 */
}

/* Container */
.container {
    width: 100%;
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--container-padding);
}

/* Section scroll margin for fixed navigation */
section[id] {
    /* 导航栏高度约为70px，添加scroll-margin-top确保点击导航链接时内容不被遮挡 */
    scroll-margin-top: 80px;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    font-weight: var(--font-bold);
    line-height: var(--leading-tight);
}

h1 {
    font-size: clamp(var(--text-4xl), 5vw, var(--text-7xl));
}

h2 {
    font-size: clamp(var(--text-3xl), 4vw, var(--text-5xl));
}

h3 {
    font-size: clamp(var(--text-2xl), 3vw, var(--text-3xl));
}

h4 {
    font-size: var(--text-xl);
}

h5 {
    font-size: var(--text-lg);
}

h6 {
    font-size: var(--text-base);
}

p {
    margin-bottom: var(--space-4);
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition-base);
}

a:hover {
    color: var(--color-primary-dark);
}

/* Gradient Text */
.gradient-text {
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Loading Screen */
.loading-screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--color-bg);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: var(--z-max);
    transition: opacity var(--transition-slow);
}

.loading-screen.hidden {
    opacity: 0;
    pointer-events: none;
}

.loader {
    text-align: center;
}

.loader-circle {
    width: 60px;
    height: 60px;
    border: 3px solid var(--color-gray-200);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    margin: 0 auto var(--space-4);
    animation: spin 1s linear infinite;
}

.loader-text {
    font-family: var(--font-display);
    font-size: var(--text-xl);
    font-weight: var(--font-bold);
    color: var(--color-primary);
}

/* Language Selector */
.language-selector {
    position: fixed;
    top: var(--space-4);
    right: var(--space-4);
    z-index: var(--z-90);
}

.lang-toggle-btn {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-2) var(--space-3);
    background: var(--color-white);
    border: 1px solid var(--color-gray-200);
    border-radius: var(--radius-lg);
    cursor: pointer;
    font-size: var(--text-sm);
    font-weight: var(--font-medium);
    transition: all var(--transition-base);
    box-shadow: var(--shadow-sm);
}

.lang-toggle-btn:hover {
    box-shadow: var(--shadow-md);
}

.lang-dropdown {
    position: absolute;
    top: calc(100% + var(--space-2));
    right: 0;
    background: var(--color-white);
    border: 1px solid var(--color-gray-200);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all var(--transition-base);
}

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

.lang-option {
    display: block;
    width: 100%;
    padding: var(--space-2) var(--space-4);
    background: none;
    border: none;
    text-align: left;
    cursor: pointer;
    font-size: var(--text-sm);
    transition: background var(--transition-base);
}

.lang-option:hover {
    background: var(--color-gray-50);
}

.lang-option.active {
    background: var(--color-primary);
    color: var(--color-white);
}

/* Navigation */
.main-nav {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-gray-200);
    z-index: var(--z-80);
    transition: all var(--transition-base);
}

.main-nav.scrolled {
    box-shadow: var(--shadow-md);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-4);
    max-width: var(--container-max-width);
    margin: 0 auto;
}

.nav-logo {
    display: flex;
    align-items: baseline;
    gap: var(--space-2);
}

.logo-link {
    display: flex;
    align-items: baseline;
    gap: var(--space-2);
    color: var(--color-gray-900);
}

.logo-text {
    font-family: var(--font-display);
    font-size: var(--text-2xl);
    font-weight: var(--font-bold);
}

.logo-subtitle {
    font-size: var(--text-sm);
    color: var(--color-gray-500);
    font-weight: var(--font-normal);
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: var(--space-10);  /* 增加间距以适应移除Analysis后的布局 */
}

.nav-link {
    font-size: var(--text-base);
    font-weight: var(--font-medium);
    color: var(--color-gray-700);
    transition: color var(--transition-base);
    position: relative;
}

.nav-link:hover {
    color: var(--color-primary);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--color-primary);
    transition: width var(--transition-base);
}

.nav-link:hover::after {
    width: 100%;
}

/* Active nav link style */
.nav-link.active {
    color: var(--color-primary);
    background-color: #E9EFFD;
    padding: var(--space-2) var(--space-4);
    border-radius: var(--radius-md);
}

.nav-link.active::after {
    width: 0; /* 移除active时的下划线，使用背景色块替代 */
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    padding: var(--space-2);
    background: none;
    border: none;
    cursor: pointer;
}

.nav-toggle span {
    width: 24px;
    height: 2px;
    background: var(--color-gray-700);
    transition: all var(--transition-base);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-6);
    font-size: var(--text-base);
    font-weight: var(--font-medium);
    border-radius: var(--radius-lg);
    border: 2px solid transparent;
    cursor: pointer;
    transition: all var(--transition-base);
    text-decoration: none;
}

.btn-primary {
    background: var(--color-primary);
    color: var(--color-white);
    border-color: var(--color-primary);
}

.btn-primary:hover {
    background: var(--color-primary-dark);
    border-color: var(--color-primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: var(--color-white);
    color: var(--color-primary);
    border-color: var(--color-primary);
}

.btn-secondary:hover {
    background: var(--color-primary);
    color: var(--color-white);
    transform: translateY(-2px);
}

.btn-outline {
    background: transparent;
    color: var(--color-gray-700);
    border-color: var(--color-gray-300);
}

.btn-outline:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
}

/* Section Spacing */
section {
    padding: var(--space-20) 0;
}

.section-title {
    margin-bottom: var(--space-12);
    text-align: center;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 70px;
        right: -100%;
        width: 100%;
        height: calc(100vh - 70px);
        background: var(--color-white);
        flex-direction: column;
        padding: var(--space-8);
        gap: var(--space-4);
        transition: right var(--transition-base);
    }
    
    .nav-menu.active {
        right: 0;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .logo-subtitle {
        display: none;
    }
    
    .language-selector {
        top: auto;
        bottom: var(--space-4);
    }
}

/* Animations */
@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideIn {
    from {
        transform: translateX(-100%);
    }
    to {
        transform: translateX(0);
    }
}



    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideIn {
    from {
        transform: translateX(-100%);
    }
    to {
        transform: translateX(0);
    }
}





    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideIn {
    from {
        transform: translateX(-100%);
    }
    to {
        transform: translateX(0);
    }
}



    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideIn {
    from {
        transform: translateX(-100%);
    }
    to {
        transform: translateX(0);
    }
}