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

body {
    font-family: 'Inter', sans-serif;
    line-height: 1.6;
    color: #e0e0e0;
    background: #1a1a1a;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(26, 26, 26, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    padding: 1rem 0;
    transition: all 0.3s ease;
    border-bottom: 1px solid #333;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    display: flex;
    align-items: center;
    font-size: 1.5rem;
    font-weight: 700;
    color: #667eea;
}

.nav-logo i {
    margin-right: 0.5rem;
    font-size: 1.8rem;
}

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

.nav-link {
    text-decoration: none;
    color: #e0e0e0;
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

.nav-link:hover {
    color: #667eea;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: #667eea;
    transition: width 0.3s ease;
}

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

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background: #e0e0e0;
    margin: 3px 0;
    transition: 0.3s;
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #1a1a1a 0%, #2d2d2d 100%);
    color: white;
    padding: 0 20px;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(45deg, transparent 48%, rgba(102, 126, 234, 0.03) 50%, transparent 52%);
    animation: shimmer 30s infinite linear;
}

@keyframes shimmer {
    0% { transform: translateX(-100px) translateY(0px); }
    100% { transform: translateX(100px) translateY(-50px); }
}

/* 添加一个hero容器来限制最大宽度 */
.hero-container {
    display: flex;
    align-items: center;
    gap: 3rem;
    max-width: 1400px;
    width: 100%;
    margin: 0 auto;
}

.hero-content {
    flex: 1;
    max-width: 600px;
    z-index: 2;
}

.hero h1 {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    line-height: 1.2;
}

.highlight {
    background: linear-gradient(45deg, #4ade80, #22c55e);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

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

.btn {
    padding: 1rem 2rem;
    border: none;
    border-radius: 50px;
    font-weight: 600;
    text-decoration: none;
    display: inline-block;
    transition: all 0.3s ease;
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background: linear-gradient(45deg, #4ade80, #22c55e);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(74, 222, 128, 0.3);
}

.btn-secondary {
    background: transparent;
    color: white;
    border: 2px solid white;
}

.btn-secondary:hover {
    background: white;
    color: #667eea;
    transform: translateY(-2px);
}

.hero-visual {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    max-width: 600px;
}

.brain-animation {
    width: 300px;
    height: 300px;
    position: relative;
}

/* Pixel Fire Animation */
.pixel-fire {
    position: absolute;
    right: 10px;
    bottom: 10px;
    width: 200px;
    height: 300px;
    z-index: 1;
}

.fire-pixel {
    position: absolute;
    width: 8px;
    height: 8px;
    background: #ff4500;
    animation: flicker 0.5s infinite alternate;
}

/* Base of fire - widest part */
.fire-pixel:nth-child(1) { left: 80px; bottom: 0px; background: #ff2500; animation-delay: 0s; }
.fire-pixel:nth-child(2) { left: 88px; bottom: 0px; background: #ff3500; animation-delay: 0.1s; }
.fire-pixel:nth-child(3) { left: 96px; bottom: 0px; background: #ff2500; animation-delay: 0.05s; }
.fire-pixel:nth-child(4) { left: 104px; bottom: 0px; background: #ff3500; animation-delay: 0.15s; }
.fire-pixel:nth-child(5) { left: 112px; bottom: 0px; background: #ff2500; animation-delay: 0.08s; }

/* Second row */
.fire-pixel:nth-child(6) { left: 72px; bottom: 8px; background: #ff4500; animation-delay: 0.2s; }
.fire-pixel:nth-child(7) { left: 80px; bottom: 8px; background: #ff3500; animation-delay: 0.1s; }
.fire-pixel:nth-child(8) { left: 88px; bottom: 8px; background: #ff4500; animation-delay: 0.3s; }
.fire-pixel:nth-child(9) { left: 96px; bottom: 8px; background: #ff3500; animation-delay: 0.15s; }
.fire-pixel:nth-child(10) { left: 104px; bottom: 8px; background: #ff4500; animation-delay: 0.25s; }
.fire-pixel:nth-child(11) { left: 112px; bottom: 8px; background: #ff3500; animation-delay: 0.12s; }
.fire-pixel:nth-child(12) { left: 120px; bottom: 8px; background: #ff4500; animation-delay: 0.18s; }

/* Third row */
.fire-pixel:nth-child(13) { left: 64px; bottom: 16px; background: #ff6500; animation-delay: 0.4s; }
.fire-pixel:nth-child(14) { left: 72px; bottom: 16px; background: #ff5500; animation-delay: 0.2s; }
.fire-pixel:nth-child(15) { left: 80px; bottom: 16px; background: #ff4500; animation-delay: 0.35s; }
.fire-pixel:nth-child(16) { left: 88px; bottom: 16px; background: #ff5500; animation-delay: 0.1s; }
.fire-pixel:nth-child(17) { left: 96px; bottom: 16px; background: #ff4500; animation-delay: 0.3s; }
.fire-pixel:nth-child(18) { left: 104px; bottom: 16px; background: #ff5500; animation-delay: 0.2s; }
.fire-pixel:nth-child(19) { left: 112px; bottom: 16px; background: #ff4500; animation-delay: 0.25s; }
.fire-pixel:nth-child(20) { left: 120px; bottom: 16px; background: #ff5500; animation-delay: 0.15s; }
.fire-pixel:nth-child(21) { left: 128px; bottom: 16px; background: #ff6500; animation-delay: 0.35s; }

/* Fourth row */
.fire-pixel:nth-child(22) { left: 56px; bottom: 24px; background: #ff8500; animation-delay: 0.5s; }
.fire-pixel:nth-child(23) { left: 64px; bottom: 24px; background: #ff7500; animation-delay: 0.3s; }
.fire-pixel:nth-child(24) { left: 72px; bottom: 24px; background: #ff6500; animation-delay: 0.4s; }
.fire-pixel:nth-child(25) { left: 80px; bottom: 24px; background: #ff5500; animation-delay: 0.2s; }
.fire-pixel:nth-child(26) { left: 88px; bottom: 24px; background: #ff6500; animation-delay: 0.35s; }
.fire-pixel:nth-child(27) { left: 96px; bottom: 24px; background: #ff5500; animation-delay: 0.1s; }
.fire-pixel:nth-child(28) { left: 104px; bottom: 24px; background: #ff6500; animation-delay: 0.3s; }
.fire-pixel:nth-child(29) { left: 112px; bottom: 24px; background: #ff5500; animation-delay: 0.25s; }
.fire-pixel:nth-child(30) { left: 120px; bottom: 24px; background: #ff6500; animation-delay: 0.15s; }
.fire-pixel:nth-child(31) { left: 128px; bottom: 24px; background: #ff7500; animation-delay: 0.4s; }
.fire-pixel:nth-child(32) { left: 136px; bottom: 24px; background: #ff8500; animation-delay: 0.45s; }

/* Fifth row */
.fire-pixel:nth-child(33) { left: 48px; bottom: 32px; background: #ffa500; animation-delay: 0.6s; }
.fire-pixel:nth-child(34) { left: 56px; bottom: 32px; background: #ff9500; animation-delay: 0.4s; }
.fire-pixel:nth-child(35) { left: 64px; bottom: 32px; background: #ff8500; animation-delay: 0.5s; }
.fire-pixel:nth-child(36) { left: 72px; bottom: 32px; background: #ff7500; animation-delay: 0.3s; }
.fire-pixel:nth-child(37) { left: 80px; bottom: 32px; background: #ff6500; animation-delay: 0.45s; }
.fire-pixel:nth-child(38) { left: 88px; bottom: 32px; background: #ff7500; animation-delay: 0.2s; }
.fire-pixel:nth-child(39) { left: 96px; bottom: 32px; background: #ff6500; animation-delay: 0.35s; }
.fire-pixel:nth-child(40) { left: 104px; bottom: 32px; background: #ff7500; animation-delay: 0.25s; }
.fire-pixel:nth-child(41) { left: 112px; bottom: 32px; background: #ff6500; animation-delay: 0.4s; }
.fire-pixel:nth-child(42) { left: 120px; bottom: 32px; background: #ff7500; animation-delay: 0.15s; }
.fire-pixel:nth-child(43) { left: 128px; bottom: 32px; background: #ff8500; animation-delay: 0.5s; }
.fire-pixel:nth-child(44) { left: 136px; bottom: 32px; background: #ff9500; animation-delay: 0.35s; }
.fire-pixel:nth-child(45) { left: 144px; bottom: 32px; background: #ffa500; animation-delay: 0.55s; }

/* Sixth row - getting narrower */
.fire-pixel:nth-child(46) { left: 56px; bottom: 40px; background: #ffb500; animation-delay: 0.7s; }
.fire-pixel:nth-child(47) { left: 64px; bottom: 40px; background: #ffa500; animation-delay: 0.5s; }
.fire-pixel:nth-child(48) { left: 72px; bottom: 40px; background: #ff9500; animation-delay: 0.6s; }
.fire-pixel:nth-child(49) { left: 80px; bottom: 40px; background: #ff8500; animation-delay: 0.4s; }
.fire-pixel:nth-child(50) { left: 88px; bottom: 40px; background: #ff7500; animation-delay: 0.55s; }
.fire-pixel:nth-child(51) { left: 96px; bottom: 40px; background: #ff8500; animation-delay: 0.3s; }
.fire-pixel:nth-child(52) { left: 104px; bottom: 40px; background: #ff7500; animation-delay: 0.45s; }
.fire-pixel:nth-child(53) { left: 112px; bottom: 40px; background: #ff8500; animation-delay: 0.35s; }
.fire-pixel:nth-child(54) { left: 120px; bottom: 40px; background: #ff9500; animation-delay: 0.25s; }
.fire-pixel:nth-child(55) { left: 128px; bottom: 40px; background: #ffa500; animation-delay: 0.6s; }
.fire-pixel:nth-child(56) { left: 136px; bottom: 40px; background: #ffb500; animation-delay: 0.5s; }

/* Seventh row */
.fire-pixel:nth-child(57) { left: 64px; bottom: 48px; background: #ffc500; animation-delay: 0.8s; }
.fire-pixel:nth-child(58) { left: 72px; bottom: 48px; background: #ffb500; animation-delay: 0.6s; }
.fire-pixel:nth-child(59) { left: 80px; bottom: 48px; background: #ffa500; animation-delay: 0.7s; }
.fire-pixel:nth-child(60) { left: 88px; bottom: 48px; background: #ff9500; animation-delay: 0.5s; }
.fire-pixel:nth-child(61) { left: 96px; bottom: 48px; background: #ff8500; animation-delay: 0.65s; }
.fire-pixel:nth-child(62) { left: 104px; bottom: 48px; background: #ff9500; animation-delay: 0.4s; }
.fire-pixel:nth-child(63) { left: 112px; bottom: 48px; background: #ffa500; animation-delay: 0.55s; }
.fire-pixel:nth-child(64) { left: 120px; bottom: 48px; background: #ffb500; animation-delay: 0.45s; }
.fire-pixel:nth-child(65) { left: 128px; bottom: 48px; background: #ffc500; animation-delay: 0.7s; }

/* Eighth row - narrower */
.fire-pixel:nth-child(66) { left: 72px; bottom: 56px; background: #ffd500; animation-delay: 0.9s; }
.fire-pixel:nth-child(67) { left: 80px; bottom: 56px; background: #ffc500; animation-delay: 0.7s; }
.fire-pixel:nth-child(68) { left: 88px; bottom: 56px; background: #ffb500; animation-delay: 0.8s; }
.fire-pixel:nth-child(69) { left: 96px; bottom: 56px; background: #ffa500; animation-delay: 0.6s; }
.fire-pixel:nth-child(70) { left: 104px; bottom: 56px; background: #ffb500; animation-delay: 0.75s; }
.fire-pixel:nth-child(71) { left: 112px; bottom: 56px; background: #ffc500; animation-delay: 0.5s; }
.fire-pixel:nth-child(72) { left: 120px; bottom: 56px; background: #ffd500; animation-delay: 0.85s; }

/* Top rows - flame tips */
.fire-pixel:nth-child(73) { left: 80px; bottom: 64px; background: #ffe500; animation-delay: 1.0s; }
.fire-pixel:nth-child(74) { left: 88px; bottom: 64px; background: #ffd500; animation-delay: 0.8s; }
.fire-pixel:nth-child(75) { left: 96px; bottom: 64px; background: #ffc500; animation-delay: 0.9s; }
.fire-pixel:nth-child(76) { left: 104px; bottom: 64px; background: #ffd500; animation-delay: 0.7s; }
.fire-pixel:nth-child(77) { left: 112px; bottom: 64px; background: #ffe500; animation-delay: 0.95s; }

.fire-pixel:nth-child(78) { left: 88px; bottom: 72px; background: #fff500; animation-delay: 1.1s; }
.fire-pixel:nth-child(79) { left: 96px; bottom: 72px; background: #ffe500; animation-delay: 0.9s; }
.fire-pixel:nth-child(80) { left: 104px; bottom: 72px; background: #fff500; animation-delay: 1.05s; }

.fire-pixel:nth-child(81) { left: 96px; bottom: 80px; background: #ffff00; animation-delay: 1.2s; }

/* 添加更多火焰顶端像素，让火焰更对称更好看 */
.fire-pixel:nth-child(82) { left: 92px; bottom: 88px; background: #ffff88; animation-delay: 1.3s; }
.fire-pixel:nth-child(83) { left: 96px; bottom: 88px; background: #ffffff; animation-delay: 1.25s; }
.fire-pixel:nth-child(84) { left: 100px; bottom: 88px; background: #ffff88; animation-delay: 1.35s; }

.fire-pixel:nth-child(85) { left: 94px; bottom: 96px; background: #ffffcc; animation-delay: 1.4s; }
.fire-pixel:nth-child(86) { left: 96px; bottom: 96px; background: #ffffff; animation-delay: 1.38s; }
.fire-pixel:nth-child(87) { left: 98px; bottom: 96px; background: #ffffcc; animation-delay: 1.42s; }

.fire-pixel:nth-child(88) { left: 95px; bottom: 104px; background: #ffffee; animation-delay: 1.5s; }
.fire-pixel:nth-child(89) { left: 96px; bottom: 104px; background: #ffffff; animation-delay: 1.48s; }
.fire-pixel:nth-child(90) { left: 97px; bottom: 104px; background: #ffffee; animation-delay: 1.52s; }

.fire-pixel:nth-child(91) { left: 96px; bottom: 112px; background: #ffffff; animation-delay: 1.6s; }

@keyframes flicker {
    0% { 
        opacity: 0.7;
        transform: translateY(0px) scale(1) rotate(0deg);
    }
    25% {
        opacity: 1;
        transform: translateY(-1px) scale(1.05) rotate(1deg);
    }
    50% {
        opacity: 0.9;
        transform: translateY(-2px) scale(1.1) rotate(-1deg);
    }
    75% {
        opacity: 1;
        transform: translateY(-1px) scale(1.05) rotate(0.5deg);
    }
    100% { 
        opacity: 0.8;
        transform: translateY(-3px) scale(0.95) rotate(0deg);
    }
}

.brain-svg {
    width: 100%;
    height: 100%;
    animation: pulse 3s ease-in-out infinite;
}

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

.neuron {
    animation: blink 2s ease-in-out infinite;
}

.neuron:nth-child(2) { animation-delay: 0.5s; }
.neuron:nth-child(3) { animation-delay: 1s; }
.neuron:nth-child(4) { animation-delay: 1.5s; }
.neuron:nth-child(5) { animation-delay: 2s; }

@keyframes blink {
    0%, 100% { opacity: 0.8; }
    50% { opacity: 1; }
}

/* Neural edge animations */
.neural-edge {
    transition: all 0.3s ease;
}

.neural-edge.active {
    stroke: #fbbf24;
    stroke-width: 2;
    opacity: 0.8;
    animation: pulse-edge 0.6s ease-out;
}

@keyframes pulse-edge {
    0% {
        stroke-width: 1;
        opacity: 0.3;
    }
    50% {
        stroke-width: 3;
        opacity: 1;
    }
    100% {
        stroke-width: 2;
        opacity: 0.8;
    }
}

/* Topics Section */
.topics {
    padding: 5rem 0;
    background: #2a2a2a;
}

.topics h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: #e0e0e0;
}

.section-subtitle {
    text-align: center;
    font-size: 1.2rem;
    color: #b0b0b0;
    margin-bottom: 3rem;
}

.topics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.topic-card {
    background: #333;
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
    transition: all 0.3s ease;
    border: 1px solid #444;
}

.topic-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
}

.topic-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(45deg, #667eea, #764ba2);
    border-radius: 15px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.5rem;
}

.topic-icon i {
    font-size: 1.5rem;
    color: white;
}

.topic-card h3 {
    font-size: 1.3rem;
    margin-bottom: 1rem;
    color: #e0e0e0;
}

.topic-card p {
    color: #b0b0b0;
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

.topic-link {
    color: #667eea;
    text-decoration: none;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    transition: all 0.3s ease;
}

.topic-link:hover {
    gap: 1rem;
}

/* Resources Section */
.resources {
    padding: 5rem 0;
    background: #1a1a1a;
}

.resources h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    color: #e0e0e0;
}

.resources-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.resource-card {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 2.5rem;
    border-radius: 20px;
    position: relative;
    overflow: hidden;
}

.resource-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><circle cx="50" cy="50" r="1" fill="%23ffffff" opacity="0.1"/></svg>') repeat;
    opacity: 0.1;
}

.resource-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1.5rem;
    position: relative;
    z-index: 2;
}

.resource-header i {
    font-size: 2rem;
}

.resource-header h3 {
    font-size: 1.5rem;
}

.resource-card p {
    margin-bottom: 1.5rem;
    opacity: 0.9;
    position: relative;
    z-index: 2;
}

.resource-card ul {
    list-style: none;
    position: relative;
    z-index: 2;
}

.resource-card li {
    padding: 0.5rem 0;
    position: relative;
    padding-left: 1.5rem;
}

.resource-card li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: #4ade80;
    font-weight: bold;
}

/* Community Section */
.community {
    padding: 5rem 0;
    background: #2a2a2a;
}

.community h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: #e0e0e0;
}

.community-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin: 3rem 0;
}

.feature {
    text-align: center;
    padding: 2rem;
}

.feature i {
    font-size: 3rem;
    color: #667eea;
    margin-bottom: 1rem;
}

.feature h3 {
    font-size: 1.3rem;
    margin-bottom: 1rem;
    color: #e0e0e0;
}

.feature p {
    color: #b0b0b0;
    line-height: 1.6;
}

.newsletter {
    background: #333;
    padding: 3rem;
    border-radius: 20px;
    text-align: center;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.3);
    margin-top: 3rem;
}

.newsletter h3 {
    font-size: 1.8rem;
    margin-bottom: 1rem;
    color: #e0e0e0;
}

.newsletter p {
    color: #b0b0b0;
    margin-bottom: 2rem;
}

.newsletter-form {
    display: flex;
    gap: 1rem;
    max-width: 400px;
    margin: 0 auto;
    flex-wrap: wrap;
}

.newsletter-form input {
    flex: 1;
    padding: 1rem;
    border: 2px solid #555;
    border-radius: 50px;
    font-size: 1rem;
    min-width: 250px;
    background: #444;
    color: #e0e0e0;
}

.newsletter-form input:focus {
    outline: none;
    border-color: #667eea;
}

/* About Section */
.about {
    padding: 5rem 0;
    background: #1a1a1a;
}

.about h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    color: #e0e0e0;
}

.about-content {
    max-width: 800px;
    margin: 0 auto;
}

.about-text p {
    font-size: 1.1rem;
    line-height: 1.8;
    color: #b0b0b0;
    margin-bottom: 2rem;
}

.stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.stat {
    text-align: center;
    padding: 1.5rem;
    background: #333;
    border-radius: 15px;
}

.stat-number {
    display: block;
    font-size: 2.5rem;
    font-weight: 700;
    color: #667eea;
    margin-bottom: 0.5rem;
}

.stat-label {
    color: #b0b0b0;
    font-weight: 500;
}

/* Footer */
/* Footer */
.footer {
    background: linear-gradient(135deg, #2d3748 0%, #1a202c 100%);
    color: white;
    padding: 4rem 0 1rem;
    position: relative;
}

.footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent 0%, #667eea 50%, transparent 100%);
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr 2fr 1fr;
    gap: 4rem;
    margin-bottom: 2rem;
    align-items: start;
}

/* 主要信息区域 */
.footer-main {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.footer-logo {
    display: flex;
    align-items: center;
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: #e2e8f0;
}

.footer-logo i {
    margin-right: 0.75rem;
    color: #667eea;
    font-size: 2rem;
}

.footer-main p {
    color: #cbd5e0;
    line-height: 1.6;
    font-size: 0.95rem;
    margin: 0;
}

.social-links {
    display: flex;
    gap: 1rem;
    margin-top: 1rem;
}

.social-links a {
    width: 44px;
    height: 44px;
    background: rgba(102, 126, 234, 0.1);
    border: 1px solid rgba(102, 126, 234, 0.3);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
    color: #cbd5e0;
    font-size: 1.1rem;
}

.social-links a:hover {
    background: #667eea;
    border-color: #667eea;
    color: white;
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(102, 126, 234, 0.3);
}

/* 链接区域 */
.footer-links {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

.footer-section h4 {
    margin-bottom: 1.5rem;
    color: #667eea;
    font-size: 1.1rem;
    font-weight: 600;
    position: relative;
}

.footer-section h4::after {
    content: '';
    position: absolute;
    bottom: -0.5rem;
    left: 0;
    width: 30px;
    height: 2px;
    background: #667eea;
    border-radius: 1px;
}

.footer-section ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.footer-section li {
    margin-bottom: 0.75rem;
}

.footer-section a {
    color: #cbd5e0;
    text-decoration: none;
    transition: all 0.3s ease;
    font-size: 0.9rem;
    display: inline-flex;
    align-items: center;
    position: relative;
}

.footer-section a::before {
    content: '';
    position: absolute;
    left: -15px;
    width: 6px;
    height: 6px;
    background: #667eea;
    border-radius: 50%;
    opacity: 0;
    transition: all 0.3s ease;
}

.footer-section a:hover {
    color: white;
    padding-left: 15px;
}

.footer-section a:hover::before {
    opacity: 1;
}

/* 联系信息区域 */
.footer-contact {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.footer-contact h4 {
    margin-bottom: 1.5rem;
    color: #667eea;
    font-size: 1.1rem;
    font-weight: 600;
    position: relative;
}

.footer-contact h4::after {
    content: '';
    position: absolute;
    bottom: -0.5rem;
    left: 0;
    width: 30px;
    height: 2px;
    background: #667eea;
    border-radius: 1px;
}

.footer-qr {
    background: rgba(255, 255, 255, 0.05);
    border-radius: 15px;
    padding: 1.5rem;
    text-align: center;
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: all 0.3s ease;
}

.footer-qr:hover {
    background: rgba(255, 255, 255, 0.08);
    border-color: rgba(102, 126, 234, 0.3);
    transform: translateY(-2px);
}

.footer-qr img {
    width: 100%;
    max-width: 200px;
    height: auto;
    object-fit: cover;
    border-radius: 12px;
    margin-bottom: 1rem;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
    transition: transform 0.3s ease;
}

.footer-qr img:hover {
    transform: scale(1.05);
}

.qr-info {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.qr-title {
    font-size: 0.95rem;
    font-weight: 600;
    color: #e2e8f0;
    margin: 0;
}

.qr-subtitle {
    font-size: 0.85rem;
    color: #a0aec0;
    margin: 0;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 10px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: all 0.3s ease;
}

.contact-item:hover {
    background: rgba(255, 255, 255, 0.08);
    border-color: rgba(102, 126, 234, 0.3);
}

.contact-item i {
    color: #667eea;
    width: 18px;
    font-size: 1rem;
    flex-shrink: 0;
}

.contact-item span {
    color: #cbd5e0;
    font-size: 0.9rem;
    word-break: break-all;
}

/* Footer底部 */
.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    margin-top: 2rem;
}

.footer-bottom p {
    color: #a0aec0;
    font-size: 0.9rem;
    margin: 0;
}

/* 响应式设计 */
@media (max-width: 1024px) {
    .footer-content {
        grid-template-columns: 1fr 1fr;
        gap: 3rem;
    }
    
    .footer-contact {
        grid-column: 1 / -1;
        margin-top: 2rem;
    }
    
    .footer-links {
        grid-template-columns: repeat(2, 1fr);
        gap: 2rem;
    }
}

@media (max-width: 768px) {
    .footer {
        padding: 3rem 0 1rem;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: 2.5rem;
        text-align: center;
    }
    
    .footer-links {
        grid-template-columns: 1fr;
        gap: 2rem;
        text-align: left;
    }
    
    .footer-section h4::after {
        left: 50%;
        transform: translateX(-50%);
    }
    
    .footer-contact h4::after {
        left: 50%;
        transform: translateX(-50%);
    }
    
    .social-links {
        justify-content: center;
    }
    
    .footer-qr {
        max-width: 280px;
        margin: 0 auto;
    }
}

@media (max-width: 480px) {
    .footer {
        padding: 2rem 0 1rem;
    }
    
    .footer-content {
        gap: 2rem;
    }
    
    .footer-logo {
        font-size: 1.6rem;
        justify-content: center;
    }
    
    .footer-logo i {
        font-size: 1.8rem;
    }
    
    .social-links a {
        width: 40px;
        height: 40px;
    }
    
    .footer-qr {
        padding: 1rem;
    }
    
    .contact-item {
        padding: 0.5rem;
    }
}

@media (max-width: 768px) {
    .hero-container {
        flex-direction: column;
        gap: 2rem;
        text-align: center;
    }
    
    .hero-content {
        max-width: 100%;
    }
    
    .hero h1 {
        font-size: 2.5rem;
    }
    
    .hero-visual {
        max-width: 100%;
    }
    
    .brain-animation {
        width: 250px;
        height: 250px;
    }
    
    .pixel-fire {
        right: 20px;
        bottom: 20px;
        width: 150px;
        height: 200px;
    }
}

@media (max-width: 480px) {
    .hero h1 {
        font-size: 2rem;
    }
    
    .brain-animation {
        width: 200px;
        height: 200px;
    }
    
    .pixel-fire {
        display: none; /* 在很小的屏幕上隐藏火焰以节省空间 */
    }
    
    .container {
        padding: 0 15px;
    }
    
    .topic-card,
    .resource-card {
        padding: 1.5rem;
    }
    
    .newsletter {
        padding: 2rem;
    }
}

/* Smooth scrolling */
html {
    scroll-behavior: smooth;
}

/* Loading animation */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.topic-card,
.resource-card,
.feature {
    animation: fadeInUp 0.6s ease-out;
}

/* Focus styles for accessibility */
.btn:focus,
.nav-link:focus,
input:focus {
    outline: 2px solid #667eea;
    outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    .hero {
        background: #000;
    }
    
    .topic-card {
        border: 2px solid #333;
    }
}

/* QR Codes Section */
.qr-codes-section {
    display: flex;
    justify-content: center;
    gap: 4rem;
    margin: 3rem 0;
    flex-wrap: wrap;
}

.qr-code-item {
    text-align: center;
    background: #333;
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
    transition: transform 0.3s ease;
    min-width: 250px;
}

.qr-code-item:hover {
    transform: translateY(-5px);
}

.qr-placeholder {
    width: 200px;
    height: 200px;
    background: #444;
    border: 2px dashed #667eea;
    border-radius: 10px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
    transition: all 0.3s ease;
    /* 添加aspect-ratio */
    aspect-ratio: 1/1;
}

.qr-placeholder:hover {
    border-color: #4ade80;
    background: #4a4a4a;
}

.qr-placeholder img {
    background-color: #444;
}

.qr-placeholder i {
    font-size: 3rem;
    color: #667eea;
    margin-bottom: 1rem;
}

.qr-placeholder p {
    color: #b0b0b0;
    font-size: 0.9rem;
    text-align: center;
    margin: 0;
    padding: 0 1rem;
}

.qr-code-item h3 {
    color: #e0e0e0;
    margin-bottom: 0.5rem;
    font-size: 1.3rem;
}

.qr-code-item p {
    color: #b0b0b0;
    margin: 0;
}

.donation-text {
    color: #ff6b6b !important;
    font-weight: 600;
    font-size: 1.1rem;
}

/* Comments Section */
.comments-section {
    background: #333;
    padding: 3rem;
    border-radius: 20px;
    margin-top: 4rem;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.3);
}

.comments-section h3 {
    color: #e0e0e0;
    margin-bottom: 2rem;
    font-size: 1.5rem;
    text-align: center;
}

.comment-form {
    margin-bottom: 3rem;
}

.comment-form textarea {
    width: 100%;
    padding: 1rem;
    border: 2px solid #555;
    border-radius: 10px;
    background: #444;
    color: #e0e0e0;
    font-family: inherit;
    font-size: 1rem;
    resize: vertical;
    margin-bottom: 1rem;
    transition: border-color 0.3s ease;
}

.comment-form textarea:focus {
    outline: none;
    border-color: #667eea;
}

.form-row {
    display: flex;
    gap: 1rem;
    align-items: center;
    flex-wrap: wrap;
}

.form-row input {
    flex: 1;
    padding: 1rem;
    border: 2px solid #555;
    border-radius: 50px;
    background: #444;
    color: #e0e0e0;
    font-size: 1rem;
    min-width: 200px;
    transition: border-color 0.3s ease;
}

.form-row input:focus {
    outline: none;
    border-color: #667eea;
}

.comments-list {
    border-top: 1px solid #555;
    padding-top: 2rem;
}

.comments-list h4 {
    color: #e0e0e0;
    margin-bottom: 1.5rem;
    font-size: 1.2rem;
}

.no-comments {
    color: #888;
    text-align: center;
    font-style: italic;
    padding: 2rem;
}

.comment-item {
    background: #444;
    padding: 1.5rem;
    border-radius: 10px;
    margin-bottom: 1rem;
    border-left: 4px solid #667eea;
    transition: transform 0.2s ease;
}

.comment-item:hover {
    transform: translateX(5px);
}

.comment-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
}

.comment-author {
    color: #667eea;
    font-weight: 600;
}

.comment-time {
    color: #888;
    font-size: 0.9rem;
}

.comment-content {
    color: #e0e0e0;
    line-height: 1.6;
    margin: 0;
}

/* Video Grid Styles */
.video-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.video-card {
    background: #333;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
    transition: all 0.3s ease;
    border: 1px solid #444;
}

.video-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.4);
}

.video-thumbnail {
    position: relative;
    width: 100%;
    height: 200px;
    overflow: hidden;
    /* 添加aspect-ratio支持 */
    aspect-ratio: 16/9;
}

.video-thumbnail img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
    /* 添加图片加载优化 */
    background-color: #444;
}

.video-card:hover .video-thumbnail img {
    transform: scale(1.05);
}

/* 为懒加载添加loading状态 */
img[loading="lazy"] {
    background-color: #444;
    background-image: linear-gradient(90deg, #444 25%, #555 50%, #444 75%);
    background-size: 200% 100%;
    animation: loading 1.5s infinite;
}

img[loading="lazy"].loaded {
    animation: none;
    background: none;
}

@keyframes loading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

.play-button {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 60px;
    height: 60px;
    background: rgba(102, 126, 234, 0.9);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.5rem;
    transition: all 0.3s ease;
    opacity: 0.8;
}

.video-card:hover .play-button {
    opacity: 1;
    transform: translate(-50%, -50%) scale(1.1);
}

.video-content {
    padding: 1.5rem;
}

.video-content h3 {
    font-size: 1.2rem;
    margin-bottom: 0.8rem;
    color: #e0e0e0;
    line-height: 1.4;
}

.video-content p {
    color: #b0b0b0;
    margin-bottom: 1rem;
    line-height: 1.6;
    font-size: 0.9rem;
}

.video-link {
    color: #667eea;
    text-decoration: none;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    transition: all 0.3s ease;
    font-size: 0.9rem;
}

.video-link:hover {
    gap: 0.8rem;
    color: #7c8ef7;
}

.video-link i {
    font-size: 1rem;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .qr-codes-section {
        flex-direction: column;
        align-items: center;
        gap: 2rem;
    }
    
    .form-row {
        flex-direction: column;
    }
    
    .form-row input {
        min-width: auto;
        width: 100%;
    }
    
    .comments-section {
        padding: 2rem;
    }
    
    .video-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .video-thumbnail {
        height: 180px;
    }
    
    .video-content {
        padding: 1.2rem;
    }
}