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

html {
    height: 100%;
    overflow-x: hidden;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #0c0c1d 0%, #1a1a2e 50%, #16213e 100%);
    color: #ffffff;
    min-height: 100vh;
    height: 100%;
    overflow-x: hidden;
    position: relative;
}

/* 星空背景 */
.starfield {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: -1;
    overflow: hidden;
    pointer-events: none;
}

.star {
    position: absolute;
    background: #ffffff;
    border-radius: 50%;
    animation: twinkle 3s infinite;
}

.star.small {
    width: 1px;
    height: 1px;
    opacity: 0.7;
}

.star.medium {
    width: 2px;
    height: 2px;
    opacity: 0.5;
}

.star.large {
    width: 3px;
    height: 3px;
    opacity: 0.3;
}

@keyframes twinkle {
    0%, 100% { opacity: 0.3; transform: scale(1); }
    50% { opacity: 1; transform: scale(1.2); }
}

/* 流星效果 */
.shooting-star {
    position: absolute;
    width: 2px;
    height: 2px;
    background: linear-gradient(45deg, #ffffff, transparent);
    border-radius: 50%;
    opacity: 0;
    animation: shoot 3s linear infinite;
}

@keyframes shoot {
    0% {
        opacity: 0;
        transform: translate(0, 0);
    }
    10% {
        opacity: 1;
    }
    90% {
        opacity: 1;
    }
    100% {
        opacity: 0;
        transform: translate(300px, 300px);
    }
}

/* 导航栏 */
header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(0, 0, 0, 0.2);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    z-index: 1000;
    padding: 1rem 2rem;
    height: 80px;
}

nav {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100%;
    gap: 2rem;
}

.nav-link {
    color: #ffffff;
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 25px;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.nav-link:hover {
    background: rgba(255, 255, 255, 0.1);
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(74, 144, 226, 0.3);
}

.nav-link.glow-text {
    text-shadow: 0 0 10px rgba(74, 144, 226, 0.5);
}

/* 主要内容 */
main {
    padding: 120px 2rem 60px;
    max-width: 1200px;
    margin: 0 auto;
    min-height: calc(100vh - 180px);
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.hero-section {
    text-align: center;
    margin-bottom: 4rem;
    flex-shrink: 0;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    background: linear-gradient(45deg, #4a90e2, #64b5f6, #90caf9);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: glow 2s ease-in-out infinite alternate;
}

@keyframes glow {
    from { text-shadow: 0 0 20px rgba(74, 144, 226, 0.5); }
    to { text-shadow: 0 0 30px rgba(74, 144, 226, 0.8); }
}

.hero-subtitle {
    font-size: 1.2rem;
    color: #b0bec5;
    margin-bottom: 2rem;
}

/* 特性网格 */
.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    flex: 1;
    align-content: center;
}

.feature-card {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 20px;
    padding: 2rem;
    text-align: center;
    transition: all 0.3s ease;
    cursor: pointer;
    position: relative;
    overflow: hidden;
    backdrop-filter: blur(10px);
    height: 200px;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(74, 144, 226, 0.1), transparent);
    transition: left 0.5s ease;
}

.feature-card:hover::before {
    left: 100%;
}

.feature-card:hover {
    transform: translateY(-10px);
    background: rgba(255, 255, 255, 0.08);
    border-color: rgba(74, 144, 226, 0.3);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.2), 0 0 20px rgba(74, 144, 226, 0.1);
}

.feature-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: #4a90e2;
}

.feature-card p {
    color: #b0bec5;
    line-height: 1.6;
}

/* 浮动动画 */
.float {
    animation: float 6s ease-in-out infinite;
}

.float:nth-child(1) { animation-delay: 0s; }
.float:nth-child(2) { animation-delay: 1s; }
.float:nth-child(3) { animation-delay: 2s; }
.float:nth-child(4) { animation-delay: 3s; }

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

/* 粒子效果 */
.particle {
    position: fixed;
    background: rgba(74, 144, 226, 0.3);
    border-radius: 50%;
    pointer-events: none;
    z-index: 10;
    animation: particle-float 15s linear infinite;
}

@keyframes particle-float {
    0% {
        transform: translateY(100vh) rotate(0deg);
        opacity: 0;
    }
    10% {
        opacity: 1;
    }
    90% {
        opacity: 1;
    }
    100% {
        transform: translateY(-100px) rotate(360deg);
        opacity: 0;
    }
}

/* 波纹效果 */
@keyframes ripple {
    to {
        transform: scale(4);
        opacity: 0;
    }
}

/* 响应式设计 */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2.5rem;
    }
    
    .feature-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    header {
        padding: 1rem;
        height: 70px;
    }
    
    nav {
        gap: 1rem;
    }
    
    main {
        padding: 100px 1rem 40px;
        min-height: calc(100vh - 140px);
    }
    
    .feature-card {
        height: 180px;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1rem;
    }
    
    .feature-card {
        padding: 1.5rem;
        height: 160px;
    }
    
    .feature-card h3 {
        font-size: 1.3rem;
    }
}

/* 页脚样式 */
#footer {
    width: 100%;
    text-align: center;
    padding: a.5rem 0;
    background: rgba(0, 0, 0, 0.2);
    color: white;
    margin-top: auto;
    position: relative;
    z-index: 10;
}

#footer .copyright {
    font-size: 0.9rem;
    font-weight: 300;
}

#footer a {
    color: white;
    text-decoration: none;
    font-weight: 400;
    transition: opacity 0.3s;
}

#footer a:hover {
    opacity: 0.8;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }
    
    .hero h1 {
        font-size: 2.5rem;
    }
    
    .hero p {
        font-size: 1.2rem;
    }
    
    .about h2 {
        font-size: 2.2rem;
    }
    
    .about p {
        font-size: 1rem;
    }
    
    .about-card {
        padding: 1.5rem;
    }
    
    #footer .copyright {
        font-size: 0.8rem;
        padding: 0 1rem;
    }
}