/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    overflow-x: hidden;
}

body {
    font-family: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: #f5f5f7;
    background: #000;
    overflow-x: hidden;
    position: relative;
    user-select: none;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
}


.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* Loading Screen */
.loading-screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: #000;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 10000;
    opacity: 1;
    visibility: visible;
    transition: opacity 0.8s ease-out, visibility 0.8s ease-out;
}


.loading-screen.hidden {
    opacity: 0;
    visibility: hidden;
}

.progress-container {
    width: 300px;
}

.progress-bar {
    width: 100%;
    height: 2px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 1px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, #007AFF, #00D4FF);
    border-radius: 1px;
    transition: width 0.3s ease-out;
    position: relative;
}

.progress-fill::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    animation: progressShimmer 2s ease-in-out infinite;
}

@keyframes progressShimmer {
    0% { transform: translateX(-100%); }
    100% { transform: translateX(300px); }
}

/* Intro Animation Container */
.intro-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: #000;
    z-index: 1000;
    display: none;
}


.intro-container.active {
    display: block;
}

.company-intro,
.earth-intro,
.final-logo {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Company Name Animation */
.company-name {
    font-size: 2.5rem;
    font-weight: 300;
    color: #f5f5f7;
    letter-spacing: 0.02em;
    opacity: 0;
    animation: companyFade 4s ease-in-out;
}

@keyframes companyFade {
    0% { opacity: 0; }
    20% { opacity: 1; }
    80% { opacity: 1; }
    100% { opacity: 0; }
}

/* Earth Animation */
.earth-intro {
    opacity: 0;
    animation: earthIntroFade 3s ease-in-out 3s forwards;
}

.earth-globe {
    width: 80vmin;
    height: 80vmin;
    border-radius: 50%;
    background: 
        radial-gradient(circle at 30% 30%, rgba(135, 206, 250, 0.8) 0%, rgba(25, 25, 112, 0.6) 50%, rgba(0, 0, 0, 0.8) 100%),
        conic-gradient(from 0deg, 
            #1e3a8a 0deg, #065f46 60deg, #92400e 120deg, 
            #1e3a8a 180deg, #065f46 240deg, #92400e 300deg, #1e3a8a 360deg);
    position: relative;
    animation: earthZoomRotate 6s ease-in-out 3s forwards;
    transform: scale(2);
}

.earth-globe::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    border-radius: 50%;
    background: 
        radial-gradient(ellipse 40% 20% at 40% 40%, rgba(255, 255, 255, 0.2) 0%, transparent 50%),
        radial-gradient(ellipse 30% 15% at 60% 20%, rgba(135, 206, 250, 0.3) 0%, transparent 40%);
    mix-blend-mode: overlay;
}

.earth-globe::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    border-radius: 50%;
    box-shadow: 
        inset 20px 20px 50px rgba(0, 0, 0, 0.3),
        inset -20px -20px 50px rgba(255, 255, 255, 0.1);
}

@keyframes earthIntroFade {
    to {
        opacity: 1;
    }
}

@keyframes earthZoomRotate {
    0% {
        transform: scale(2) rotate(0deg);
    }
    100% {
        transform: scale(0.3) rotate(360deg);
    }
}

/* Final Logo */
.final-logo {
    opacity: 0;
    animation: logoFadeIn 2s ease-out 7s forwards;
    gap: 3rem;
}

.logo-chinese,
.logo-english {
    font-size: 4rem;
    font-weight: 700;
    margin: 0;
    text-shadow: 0 0 30px rgba(255, 255, 255, 0.3);
}

.logo-chinese {
    font-family: 'Noto Sans SC', sans-serif;
    color: #007AFF;
}

.logo-english {
    font-family: 'Inter', sans-serif;
    color: #f5f5f7;
    font-weight: 300;
}

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

/* Main Content */
.main-content {
    position: relative;
    z-index: 1;
    transform: translateY(100vh);
    transition: transform 1.2s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}


.main-content.slide-in {
    transform: translateY(0);
}

/* Hero Section */
.hero-section {
    min-height: 100vh;
    background: linear-gradient(180deg, #000 0%, #1a1a1a 100%);
    display: flex;
    align-items: center;
    padding: 4rem 0;
}

.hero-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-text {
    max-width: 600px;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    line-height: 1.1;
    margin-bottom: 2rem;
    font-family: 'Noto Sans SC', sans-serif;
    background: linear-gradient(45deg, #007AFF, #00D4FF);
    background-clip: text;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-subtitle {
    font-size: 1.2rem;
    color: #a1a1aa;
    margin-bottom: 3rem;
    line-height: 1.5;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
}

.btn {
    padding: 1rem 2rem;
    border: none;
    border-radius: 50px;
    font-size: 1.1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-block;
}

.btn-primary {
    background: linear-gradient(45deg, #007AFF, #00D4FF);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(0, 122, 255, 0.3);
}

.btn-secondary {
    background: transparent;
    color: #f5f5f7;
    border: 1px solid #333;
}

.btn-secondary:hover {
    background: #f5f5f7;
    color: #000;
    transform: translateY(-2px);
}

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

.hero-earth {
    width: 400px;
    height: 400px;
    border-radius: 50%;
    background: 
        radial-gradient(circle at 30% 30%, rgba(135, 206, 250, 0.8) 0%, rgba(25, 25, 112, 0.6) 50%, rgba(0, 0, 0, 0.8) 100%),
        conic-gradient(from 0deg, 
            #1e3a8a 0deg, #065f46 60deg, #92400e 120deg, 
            #1e3a8a 180deg, #065f46 240deg, #92400e 300deg, #1e3a8a 360deg);
    position: relative;
    animation: heroEarthRotate 30s linear infinite;
    box-shadow: 
        0 0 50px rgba(0, 122, 255, 0.3),
        inset 20px 20px 50px rgba(0, 0, 0, 0.3);
}

@keyframes heroEarthRotate {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

/* Features Section */
.features-section {
    background: #1a1a1a;
    padding: 8rem 0;
}

.feature-item {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
    margin-bottom: 8rem;
    opacity: 0;
    transform: translateY(50px);
    transition: all 0.8s ease-out;
}

.feature-item.visible {
    opacity: 1;
    transform: translateY(0);
}

.feature-item.feature-reverse {
    grid-template-columns: 1fr 1fr;
}

.feature-item.feature-reverse .feature-content {
    order: 2;
}

.feature-item.feature-reverse .feature-visual {
    order: 1;
}

.feature-content h2 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 2rem;
    font-family: 'Noto Sans SC', sans-serif;
    color: #f5f5f7;
}

.feature-content p {
    font-size: 1.3rem;
    color: #a1a1aa;
    line-height: 1.6;
}

.feature-visual {
    height: 400px;
    border-radius: 20px;
    position: relative;
    overflow: hidden;
}

.physics-visual {
    background: 
        radial-gradient(circle at 20% 50%, rgba(0, 122, 255, 0.3) 0%, transparent 50%),
        radial-gradient(circle at 80% 50%, rgba(255, 45, 85, 0.3) 0%, transparent 50%),
        linear-gradient(45deg, #1a1a1a, #2a2a2a);
}

.character-visual {
    background: 
        linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.world-visual {
    background: 
        linear-gradient(180deg, #000428 0%, #004e92 100%),
        radial-gradient(ellipse at center, rgba(255, 255, 255, 0.1) 0%, transparent 70%);
}

.progress-visual {
    background: 
        linear-gradient(45deg, #ff9a9e 0%, #fecfef 50%, #fecfef 100%);
}

/* Feature SVG Styles */
.feature-svg {
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    z-index: 2;
}

.feature-visual {
    position: relative;
}

/* SVG animations pause when not visible */
.feature-item:not(.visible) .feature-svg * {
    animation-play-state: paused;
}

.feature-item.visible .feature-svg * {
    animation-play-state: running;
}


/* Footer */
.footer-section {
    padding: 4rem 0;
    background: #1a1a1a;
    text-align: center;
    border-top: 1px solid #333;
}

.footer-content p {
    color: #666;
    margin-bottom: 1rem;
    font-size: 0.9rem;
}

/* Prevent scrolling during animations */
body.loading,
body.intro-playing {
    overflow: hidden;
}


/* Button hover effects */
.btn:hover {
    filter: brightness(1.1);
}


/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 0 1rem;
    }
    
    .company-name {
        font-size: 1.8rem;
    }
    
    .logo-chinese,
    .logo-english {
        font-size: 2.5rem;
    }
    
    .final-logo {
        gap: 1.5rem;
        flex-direction: column;
        text-align: center;
    }
    
    .hero-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
        text-align: center;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-earth {
        width: 300px;
        height: 300px;
    }
    
    .feature-item,
    .feature-item.feature-reverse {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 2rem;
    }
    
    .feature-item.feature-reverse .feature-content,
    .feature-item.feature-reverse .feature-visual {
        order: initial;
    }
    
    .feature-content h2 {
        font-size: 2rem;
    }
    
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .btn {
        width: 200px;
    }
}

@media (max-width: 480px) {
    .progress-container {
        width: 250px;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .feature-content h2 {
        font-size: 1.5rem;
    }
    
    .hero-earth {
        width: 250px;
        height: 250px;
    }
}