/* ==========================================================================
   Nereus - 全局样式文件
   配色方案基于品牌Logo: 深蓝色主调 + 金黄色点缀
   ========================================================================== */

/* CSS变量定义 */
:root {
    /* 主色调 - 基于Logo */
    --primary-blue: #2832B4;
    --primary-navy: #1E2875;
    --primary-gold: #FFB800;
    --accent-orange: #FF9500;
    
    /* 渐变色 */
    --gradient-primary: linear-gradient(135deg, #2832B4 0%, #1E2875 100%);
    --gradient-gold: linear-gradient(135deg, #FFB800 0%, #FF9500 100%);
    --gradient-overlay: linear-gradient(135deg, rgba(40, 50, 180, 0.9) 0%, rgba(30, 40, 117, 0.95) 100%);
    
    /* 中性色 */
    --white: #FFFFFF;
    --off-white: #F8F9FD;
    --light-gray: #E8EAEF;
    --medium-gray: #A0A6B5;
    --dark-gray: #464B5A;
    --black: #1A1D29;
    
    /* 功能色 */
    --success: #10B981;
    --warning: #F59E0B;
    --error: #EF4444;
    --info: #3B82F6;
    
    /* 阴影 */
    --shadow-sm: 0 2px 8px rgba(40, 50, 180, 0.08);
    --shadow-md: 0 4px 16px rgba(40, 50, 180, 0.12);
    --shadow-lg: 0 8px 32px rgba(40, 50, 180, 0.16);
    --shadow-xl: 0 16px 48px rgba(40, 50, 180, 0.2);
    --shadow-glow: 0 0 40px rgba(255, 184, 0, 0.3);
    
    /* 间距系统 */
    --space-xs: 0.5rem;
    --space-sm: 1rem;
    --space-md: 1.5rem;
    --space-lg: 2rem;
    --space-xl: 3rem;
    --space-2xl: 4rem;
    --space-3xl: 6rem;
    
    /* 字体 */
    --font-primary: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-heading: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    
    /* 圆角 */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --radius-2xl: 24px;
    --radius-full: 9999px;
    
    /* 动画时长 */
    --transition-fast: 0.15s;
    --transition-base: 0.3s;
    --transition-slow: 0.5s;
    
    /* Z-index层级 */
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-fixed: 1030;
    --z-modal-backdrop: 1040;
    --z-modal: 1050;
    --z-popover: 1060;
    --z-tooltip: 1070;
}

/* ==========================================================================
   重置和基础样式
   ========================================================================== */

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--black);
    background-color: var(--off-white);
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ==========================================================================
   排版
   ========================================================================== */

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    line-height: 1.2;
    color: var(--primary-navy);
    margin-bottom: var(--space-md);
}

h1 { font-size: 3.5rem; letter-spacing: -0.02em; }
h2 { font-size: 2.5rem; letter-spacing: -0.01em; }
h3 { font-size: 2rem; }
h4 { font-size: 1.5rem; }
h5 { font-size: 1.25rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: var(--space-md);
    color: var(--dark-gray);
}

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

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

/* ==========================================================================
   头部导航栏
   ========================================================================== */

.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: var(--z-fixed);
    background: transparent;
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
    border-bottom: 1px solid transparent;
    transition: all var(--transition-base) ease;
}

.header.scrolled {
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(40, 50, 180, 0.1);
    box-shadow: var(--shadow-md);
}

.header-container {
    max-width: 1600px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 80px;
}

.logo-link {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    transition: transform var(--transition-base) ease;
}

.logo-link:hover {
    transform: scale(1.05);
}

.logo-img {
    height: 40px;
    width: auto;
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.2));
    transition: filter var(--transition-base) ease;
}

.header.scrolled .logo-img {
    filter: none;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--space-md);
    align-items: center;
    flex-wrap: nowrap;
}

.nav-link {
    position: relative;
    font-weight: 500;
    color: var(--white);
    padding: var(--space-xs) var(--space-sm);
    transition: all var(--transition-base) ease;
    white-space: nowrap;
    font-size: 0.938rem;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.header.scrolled .nav-link {
    color: var(--primary-navy);
    text-shadow: none;
}

.nav-link::before {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 50%;
    transform: translateX(-50%) scaleX(0);
    width: 100%;
    height: 3px;
    background: var(--gradient-gold);
    border-radius: var(--radius-full);
    transition: transform var(--transition-base) ease;
}

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

.header.scrolled .nav-link:hover,
.header.scrolled .nav-link.active {
    color: var(--primary-blue);
}

.nav-link:hover::before,
.nav-link.active::before {
    transform: translateX(-50%) scaleX(1);
}

.mobile-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--space-xs);
}

.mobile-toggle span {
    display: block;
    width: 25px;
    height: 3px;
    background: var(--white);
    border-radius: var(--radius-full);
    transition: all var(--transition-base) ease;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.header.scrolled .mobile-toggle span {
    background: var(--primary-navy);
    box-shadow: none;
}

/* ==========================================================================
   按钮组件
   ========================================================================== */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-xs);
    padding: var(--space-sm) var(--space-lg);
    font-weight: 600;
    font-size: 1rem;
    border-radius: var(--radius-md);
    border: 2px solid transparent;
    cursor: pointer;
    transition: all var(--transition-base) ease;
    text-decoration: none;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.3);
    transform: translate(-50%, -50%);
    transition: width var(--transition-slow) ease, height var(--transition-slow) ease;
}

.btn:hover::before {
    width: 300px;
    height: 300px;
}

.btn-primary {
    background: var(--gradient-gold);
    color: var(--primary-navy);
    box-shadow: var(--shadow-md);
    font-size: 0.938rem;
    padding: 0.75rem 1.5rem;
}

/* 导航栏中的按钮在透明状态下需要更明显的阴影 */
.header .btn-primary {
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.3);
}

.header.scrolled .btn-primary {
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.btn-secondary {
    background: var(--gradient-primary);
    color: var(--white);
    box-shadow: var(--shadow-md);
}

.btn-secondary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-outline {
    background: transparent;
    border-color: var(--primary-blue);
    color: var(--primary-blue);
}

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

.btn-ghost {
    background: transparent;
    color: var(--primary-navy);
}

.btn-ghost:hover {
    background: rgba(40, 50, 180, 0.1);
}

/* ==========================================================================
   容器和布局
   ========================================================================== */

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

.container-wide {
    max-width: 1600px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

.container-sm {
    max-width: 900px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

.section {
    padding: var(--space-3xl) 0;
    position: relative;
}

.section-header {
    text-align: center;
    margin-bottom: var(--space-3xl);
    position: relative;
}

.section-subtitle {
    display: inline-block;
    font-size: 0.875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--primary-gold);
    margin-bottom: var(--space-sm);
}

.section-title {
    font-size: 2.5rem;
    margin-bottom: var(--space-md);
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.section-description {
    font-size: 1.125rem;
    color: var(--medium-gray);
    max-width: 700px;
    margin: 0 auto;
}

/* ==========================================================================
   卡片组件
   ========================================================================== */

.card {
    background: var(--white);
    border-radius: var(--radius-xl);
    padding: var(--space-xl);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base) ease;
    border: 1px solid rgba(40, 50, 180, 0.1);
}

.card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

.card-glass {
    background: rgba(255, 255, 255, 0.7);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.5);
}

.card-gradient {
    background: var(--gradient-primary);
    color: var(--white);
}

.card-gradient h3,
.card-gradient h4,
.card-gradient p {
    color: var(--white);
}

/* ==========================================================================
   动画效果
   ========================================================================== */

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInScale {
    from {
        opacity: 0;
        transform: scale(0.9);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

@keyframes slideInLeft {
    from {
        opacity: 0;
        transform: translateX(-50px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(50px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes float {
    0%, 100% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-20px);
    }
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
        transform: scale(1);
    }
    50% {
        opacity: 0.8;
        transform: scale(1.05);
    }
}

@keyframes glow {
    0%, 100% {
        box-shadow: 0 0 20px rgba(255, 184, 0, 0.3);
    }
    50% {
        box-shadow: 0 0 40px rgba(255, 184, 0, 0.6);
    }
}

.animate-fade-in {
    animation: fadeIn 0.8s ease-out forwards;
}

.animate-fade-in-scale {
    animation: fadeInScale 0.6s ease-out forwards;
}

.animate-slide-in-left {
    animation: slideInLeft 0.8s ease-out forwards;
}

.animate-slide-in-right {
    animation: slideInRight 0.8s ease-out forwards;
}

.animate-float {
    animation: float 3s ease-in-out infinite;
}

.animate-pulse {
    animation: pulse 2s ease-in-out infinite;
}

.animate-glow {
    animation: glow 2s ease-in-out infinite;
}

/* ==========================================================================
   页脚
   ========================================================================== */

.footer {
    background: linear-gradient(135deg, #1E2875 0%, #2832B4 100%);
    color: var(--white);
    padding: var(--space-3xl) 0 var(--space-lg);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--space-2xl);
    margin-bottom: var(--space-2xl);
}

.footer-section h3 {
    color: var(--white);
    margin-bottom: var(--space-md);
    font-size: 1.25rem;
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: var(--space-sm);
}

.footer-links a {
    color: rgba(255, 255, 255, 0.8);
    transition: all var(--transition-base) ease;
}

.footer-links a:hover {
    color: var(--primary-gold);
    padding-left: 5px;
}

.footer-bottom {
    text-align: center;
    padding-top: var(--space-lg);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.7);
}

.social-links {
    display: flex;
    gap: var(--space-md);
    margin-top: var(--space-md);
}

.social-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-full);
    color: var(--white);
    transition: all var(--transition-base) ease;
}

.social-link:hover {
    background: var(--primary-gold);
    color: var(--primary-navy);
    transform: translateY(-3px);
}

/* ==========================================================================
   响应式设计
   ========================================================================== */

@media (max-width: 1200px) {
    .nav-menu {
        gap: var(--space-sm);
    }
    
    .nav-link {
        padding: var(--space-xs) 0.5rem;
        font-size: 0.875rem;
    }
}

@media (max-width: 1024px) {
    h1 { font-size: 2.5rem; }
    h2 { font-size: 2rem; }
    h3 { font-size: 1.5rem; }
    
    .section {
        padding: var(--space-2xl) 0;
    }
    
    .section-header {
        margin-bottom: var(--space-2xl);
    }
}

@media (max-width: 768px) {
    .header-container {
        height: 70px;
    }
    
    .nav-menu {
        position: fixed;
        top: 70px;
        left: 0;
        width: 100%;
        height: 0;
        overflow: hidden;
        flex-direction: column;
        background: rgba(255, 255, 255, 0.98);
        backdrop-filter: blur(20px);
        gap: 0;
        box-shadow: var(--shadow-lg);
        transition: height var(--transition-base) ease;
    }
    
    .nav-menu.active {
        height: auto;
        padding: var(--space-lg) 0;
    }
    
    .nav-link {
        width: 100%;
        text-align: center;
        padding: var(--space-md);
    }
    
    .mobile-toggle {
        display: flex;
    }
    
    .mobile-toggle.active span:nth-child(1) {
        transform: rotate(45deg) translate(8px, 8px);
    }
    
    .mobile-toggle.active span:nth-child(2) {
        opacity: 0;
    }
    
    .mobile-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(7px, -7px);
    }
    
    h1 { font-size: 2rem; }
    h2 { font-size: 1.75rem; }
    
    .section {
        padding: var(--space-xl) 0;
    }
    
    .container,
    .container-sm {
        padding: 0 var(--space-md);
    }
}

@media (max-width: 480px) {
    h1 { font-size: 1.75rem; }
    h2 { font-size: 1.5rem; }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
}

/* ==========================================================================
   工具类
   ========================================================================== */

.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mt-0 { margin-top: 0; }
.mt-1 { margin-top: var(--space-sm); }
.mt-2 { margin-top: var(--space-md); }
.mt-3 { margin-top: var(--space-lg); }
.mt-4 { margin-top: var(--space-xl); }

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: var(--space-sm); }
.mb-2 { margin-bottom: var(--space-md); }
.mb-3 { margin-bottom: var(--space-lg); }
.mb-4 { margin-bottom: var(--space-xl); }

.pt-0 { padding-top: 0; }
.pt-1 { padding-top: var(--space-sm); }
.pt-2 { padding-top: var(--space-md); }
.pt-3 { padding-top: var(--space-lg); }
.pt-4 { padding-top: var(--space-xl); }

.pb-0 { padding-bottom: 0; }
.pb-1 { padding-bottom: var(--space-sm); }
.pb-2 { padding-bottom: var(--space-md); }
.pb-3 { padding-bottom: var(--space-lg); }
.pb-4 { padding-bottom: var(--space-xl); }

.d-none { display: none; }
.d-block { display: block; }
.d-flex { display: flex; }
.d-grid { display: grid; }

.flex-center {
    display: flex;
    align-items: center;
    justify-content: center;
}

.gap-1 { gap: var(--space-sm); }
.gap-2 { gap: var(--space-md); }
.gap-3 { gap: var(--space-lg); }
.gap-4 { gap: var(--space-xl); }