:root {
    --primary-color: #0a192f;
    --secondary-color: #172a45;
    --accent-color: #64ffda;
    --text-color: #8892b0;
    --heading-color: #ccd6f6;
    --white: #e6f1ff;
    --font-main: "SimSun", "Songti SC", "Songti", serif;
}

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

body {
    font-family: var(--font-main);
    background-color: var(--primary-color);
    color: var(--text-color);
    line-height: 1.6;
    overflow-x: hidden;
}

/* Background Animation */
.background-animation {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    background: radial-gradient(circle at 50% 50%, #112240 0%, #0a192f 100%);
    opacity: 0.5;
}

/* Header & Nav */
header {
    position: fixed;
    top: 0;
    width: 100%;
    background-color: rgba(10, 25, 47, 0.95);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0,0,0,0.3);
    backdrop-filter: blur(10px);
}

.logo h1 {
    color: var(--accent-color);
    font-size: 1.5rem;
    line-height: 1.2;
}

.logo .subtitle {
    font-size: 0.8rem;
    color: var(--heading-color);
    letter-spacing: 1px;
}

nav ul {
    display: flex;
    list-style: none;
    gap: 2rem;
}

nav ul li {
    cursor: pointer;
    color: var(--heading-color);
    font-size: 1rem;
    transition: color 0.3s ease;
    position: relative;
    padding-bottom: 5px;
}

nav ul li:hover, nav ul li.active {
    color: var(--accent-color);
}

nav ul li::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: 0;
    left: 0;
    background-color: var(--accent-color);
    transition: width 0.3s ease;
}

nav ul li:hover::after, nav ul li.active::after {
    width: 100%;
}
#about .content-block p {
    text-indent: 2em;
    margin-bottom: 1rem;
}
.lang-switch button {
    background: transparent;
    border: 1px solid var(--accent-color);
    color: var(--accent-color);
    padding: 0.5rem 1rem;
    border-radius: 4px;
    cursor: pointer;
    font-family: var(--font-main);
    transition: all 0.3s ease;
}

.lang-switch button:hover {
    background: rgba(100, 255, 218, 0.1);
}

/* Main Content */
main {
    margin-top: 80px; /* Header height */
    min-height: calc(100vh - 140px);
}

section {
    display: none;
    padding: 4rem 2rem;
    animation: fadeIn 0.8s ease forwards;
}

section.active-section {
    display: block;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
}

h2 {
    color: var(--heading-color);
    font-size: 2.5rem;
    margin-bottom: 2rem;
    text-align: center;
    position: relative;
}

h2::after {
    content: '';
    display: block;
    width: 60px;
    height: 3px;
    background-color: var(--accent-color);
    margin: 10px auto 0;
}

h3 {
    color: var(--heading-color);
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

/* Home Section */
#home {
    padding-top: 2rem;
}

.hero-content {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 4rem;
    min-height: 80vh;
    max-width: 1200px;
    margin: 0 auto;
}

.hero-text {
    flex: 1;
}

.hero-text h2 {
    text-align: left;
    font-size: 3rem;
    margin-bottom: 1.5rem;
    color: var(--white);
}

.hero-text h2::after {
    margin: 10px 0 0;
}

.hero-text p {
    font-size: 1.2rem;
    color: var(--text-color);
}

.hero-image-container {
    flex: 1;
    display: flex;
    justify-content: center;
    position: relative;
}

.hero-image-container img {
    max-width: 100%;
    max-height: 70vh;
    border-radius: 10px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.5);
    border: 2px solid var(--secondary-color);
    transition: transform 0.3s ease;
}

.hero-image-container img:hover {
    transform: translateY(-10px);
}

/* Cards Grid (Services) */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.card {
    background-color: var(--secondary-color);
    padding: 2rem;
    border-radius: 8px;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid transparent;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0,0,0,0.3);
    border-color: var(--accent-color);
}

.card i {
    font-size: 2.5rem;
    color: var(--accent-color);
    margin-bottom: 1.5rem;
}

/* Feature List (Why Us) */
.feature-list {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.feature-item {
    display: flex;
    align-items: flex-start;
    background-color: rgba(23, 42, 69, 0.5);
    padding: 1.5rem;
    border-radius: 8px;
    transition: background-color 0.3s ease;
}

.feature-item:hover {
    background-color: var(--secondary-color);
}

.feature-icon {
    min-width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: rgba(100, 255, 218, 0.1);
    border-radius: 50%;
    margin-right: 1.5rem;
    color: var(--accent-color);
    font-size: 1.5rem;
}

/* Mission Circle */
.mission-circle {
    display: flex;
    justify-content: center;
    gap: 3rem;
    flex-wrap: wrap;
    margin-top: 3rem;
}

.circle-item {
    width: 200px;
    height: 200px;
    background-color: var(--secondary-color);
    border-radius: 50%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    border: 2px solid var(--accent-color);
    box-shadow: 0 0 20px rgba(100, 255, 218, 0.2);
    transition: transform 0.3s ease;
    text-align: center;
    padding: 1rem;
}

.circle-item:hover {
    transform: scale(1.05);
    background-color: rgba(100, 255, 218, 0.1);
}

.circle-item h3 {
    color: var(--accent-color);
    margin-bottom: 0.5rem;
}

/* Privacy */
.privacy-content {
    background-color: var(--secondary-color);
    padding: 2rem;
    border-radius: 8px;
}

.privacy-content ol {
    margin-left: 1.5rem;
    margin-top: 1rem;
}

.privacy-content li {
    margin-bottom: 1rem;
}

/* Contact */
.center-text {
    text-align: center;
}

.contact-info {
    margin-top: 3rem;
    display: flex;
    justify-content: center;
    gap: 4rem;
    flex-wrap: wrap;
}

.contact-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
}

.contact-item i {
    font-size: 2rem;
    color: var(--accent-color);
}

/* Footer */
footer {
    text-align: center;
    padding: 2rem;
    color: var(--text-color);
    font-size: 0.9rem;
    background-color: var(--secondary-color);
}

/* Utilities - Language Switching */
body:not(.en-mode) .lang-en {
    display: none !important;
}

body.en-mode .lang-zh {
    display: none !important;
}

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

.animate-text {
    opacity: 0;
    animation: fadeIn 0.8s ease forwards;
}

.delay-1 {
    animation-delay: 0.2s;
}

.animate-img {
    opacity: 0;
    animation: fadeIn 1s ease forwards;
    animation-delay: 0.4s;
}

/* Responsive */
@media (max-width: 768px) {
    header {
        flex-direction: column;
        padding: 1rem;
    }
    
    nav ul {
        margin-top: 1rem;
        gap: 1rem;
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .hero-content {
        flex-direction: column-reverse;
        text-align: center;
        gap: 2rem;
    }
    
    .hero-text h2 {
        text-align: center;
        font-size: 2rem;
    }
    
    .hero-text h2::after {
        margin: 10px auto;
    }
    
    .hero-image-container img {
        max-height: 50vh;
    }
    
    .mission-circle {
        gap: 1.5rem;
    }
    
    .circle-item {
        width: 150px;
        height: 150px;
    }
}