/* OpenAI风格全局样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

:root {
    --openai-bg: #FFFFFF;
    --openai-bg-secondary: #F7F7F8;
    --openai-bg-tertiary: #ECECF1;
    --openai-text-primary: #202123;
    --openai-text-secondary: #565869;
    --openai-text-tertiary: #8E8EA0;
    --openai-border: #E5E5E6;
    --openai-accent: #0066FF;
    --openai-accent-hover: #0052CC;
    --openai-card: #FFFFFF;
    --openai-card-hover: #FAFAFA;
    --openai-shadow: rgba(0, 0, 0, 0.08);
    --openai-shadow-hover: rgba(0, 0, 0, 0.12);
}

@media (prefers-color-scheme: dark) {
    :root {
        --openai-bg: #343541;
        --openai-bg-secondary: #40414F;
        --openai-bg-tertiary: #565869;
        --openai-text-primary: #ECECF1;
        --openai-text-secondary: #C5C5D2;
        --openai-text-tertiary: #8E8EA0;
        --openai-border: #565869;
        --openai-accent: #0066FF;
        --openai-accent-hover: #0052CC;
        --openai-card: #40414F;
        --openai-card-hover: #4A4B5A;
        --openai-shadow: rgba(0, 0, 0, 0.3);
        --openai-shadow-hover: rgba(0, 0, 0, 0.4);
    }
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica Neue', 'Arial', sans-serif;
    background: var(--openai-bg);
    color: var(--openai-text-primary);
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    line-height: 1.6;
    font-size: 16px;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    width: 100%;
    min-height: 100vh;
    position: relative;
    display: flex;
    flex-direction: column;
    background: var(--openai-bg);
}

/* OpenAI风格顶部导航 */
.top-nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: var(--openai-bg);
    border-bottom: 1px solid var(--openai-border);
    padding: 16px 24px;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

.nav-content {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo-section {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo-section h1 {
    font-size: 20px;
    font-weight: 600;
    color: var(--openai-text-primary);
    letter-spacing: -0.5px;
    margin: 0;
}

.logo-section p {
    font-size: 14px;
    color: var(--openai-text-secondary);
    margin: 0;
    display: none;
}

@media (min-width: 768px) {
    .logo-section p {
        display: block;
    }
}

.nav-actions {
    display: flex;
    gap: 12px;
    align-items: center;
}

.nav-button {
    padding: 8px 16px;
    background: transparent;
    border: 1px solid var(--openai-border);
    border-radius: 6px;
    color: var(--openai-text-primary);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    text-decoration: none;
}

.nav-button:hover {
    background: var(--openai-bg-secondary);
    border-color: var(--openai-accent);
}

.nav-button.primary {
    background: var(--openai-accent);
    border-color: var(--openai-accent);
    color: white;
}

.nav-button.primary:hover {
    background: var(--openai-accent-hover);
    border-color: var(--openai-accent-hover);
}

/* OpenAI风格主内容区 */
.main-content {
    margin-top: 73px;
    padding: 48px 24px 120px;
    max-width: 1400px;
    width: 100%;
    margin-left: auto;
    margin-right: auto;
    min-height: calc(100vh - 73px - 80px);
}

.hero-section {
    text-align: center;
    margin-bottom: 64px;
}

.typing-cursor {
    display: inline-block;
    animation: blink 1s infinite;
    color: var(--openai-accent);
    font-weight: 100;
    margin-left: 2px;
}

@keyframes blink {
    0%, 50% {
        opacity: 1;
    }
    51%, 100% {
        opacity: 0;
    }
}

/* 宣传视频区域 */
.video-section {
    margin-bottom: 64px;
    width: 100%;
    opacity: 0;
    animation: fadeInUp 0.8s ease 1.5s forwards;
}

.video-container {
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
}

.promo-video {
    width: 100%;
    height: auto;
    border-radius: 16px;
    box-shadow: 0 8px 24px var(--openai-shadow);
    background: var(--openai-bg-secondary);
    border: 1px solid var(--openai-border);
    display: block;
    transition: box-shadow 0.3s ease;
}

.promo-video:hover {
    box-shadow: 0 12px 32px var(--openai-shadow-hover);
}

.video-credit {
    text-align: center;
    font-size: 14px;
    color: var(--openai-text-tertiary);
    margin-top: 12px;
    margin-bottom: 0;
    letter-spacing: 0.2px;
}

.hero-section h2 {
    font-size: 48px;
    font-weight: 700;
    color: var(--openai-text-primary);
    margin-bottom: 16px;
    letter-spacing: -1px;
    line-height: 1.2;
}

.hero-section p {
    font-size: 20px;
    color: var(--openai-text-secondary);
    max-width: 700px;
    margin: 0 auto;
    line-height: 1.6;
}

@media (max-width: 768px) {
    .hero-section h2 {
        font-size: 32px;
    }
    
    .hero-section p {
        font-size: 18px;
    }
}

/* OpenAI风格LOGO网格 */
.logo-wall {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 48px;
}

.logo-item {
    background: var(--openai-card);
    border: 1px solid var(--openai-border);
    border-radius: 12px;
    padding: 24px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    text-decoration: none;
    color: inherit;
    opacity: 0;
    animation: fadeInUp 0.6s ease forwards;
}

.logo-item:nth-child(1) { animation-delay: 0.1s; }
.logo-item:nth-child(2) { animation-delay: 0.15s; }
.logo-item:nth-child(3) { animation-delay: 0.2s; }
.logo-item:nth-child(4) { animation-delay: 0.25s; }
.logo-item:nth-child(5) { animation-delay: 0.3s; }
.logo-item:nth-child(6) { animation-delay: 0.35s; }
.logo-item:nth-child(7) { animation-delay: 0.4s; }
.logo-item:nth-child(8) { animation-delay: 0.45s; }
.logo-item:nth-child(9) { animation-delay: 0.5s; }
.logo-item:nth-child(10) { animation-delay: 0.55s; }
.logo-item:nth-child(11) { animation-delay: 0.6s; }
.logo-item:nth-child(12) { animation-delay: 0.65s; }
.logo-item:nth-child(13) { animation-delay: 0.7s; }
.logo-item:nth-child(14) { animation-delay: 0.75s; }
.logo-item:nth-child(15) { animation-delay: 0.8s; }
.logo-item:nth-child(16) { animation-delay: 0.85s; }
.logo-item:nth-child(17) { animation-delay: 0.9s; }
.logo-item:nth-child(18) { animation-delay: 0.95s; }
.logo-item:nth-child(19) { animation-delay: 1s; }
.logo-item:nth-child(20) { animation-delay: 1.05s; }

.logo-item:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px var(--openai-shadow-hover);
    border-color: var(--openai-accent);
    background: var(--openai-card-hover);
}

.logo-item:active {
    transform: translateY(-2px);
}

.logo-item.main-logo {
    grid-column: 1 / -1;
    padding: 48px;
    background: linear-gradient(135deg, var(--openai-accent) 0%, var(--openai-accent-hover) 100%);
    border-color: var(--openai-accent);
    color: white;
}

.logo-item.main-logo:hover {
    box-shadow: 0 12px 32px rgba(0, 102, 255, 0.3);
}

.logo-item.main-logo .logo-name {
    color: white;
}

.logo-content {
    width: 64px;
    height: 64px;
    border-radius: 12px;
    background: var(--openai-bg-secondary);
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 28px;
    color: var(--openai-accent);
    transition: all 0.3s ease;
}

.logo-item.main-logo .logo-content {
    width: 96px;
    height: 96px;
    background: rgba(255, 255, 255, 0.2);
    color: white;
    backdrop-filter: blur(10px);
}

.logo-item.main-logo .logo-content span {
    font-size: 40px;
    font-weight: 700;
}

.logo-name {
    font-size: 16px;
    font-weight: 500;
    color: var(--openai-text-primary);
    text-align: center;
    letter-spacing: -0.2px;
}

.logo-item.main-logo .logo-name {
    font-size: 24px;
    font-weight: 600;
    color: white;
}

/* OpenAI风格底部导航 */
.bottom-nav {
    position: fixed;
    bottom: 28px;
    left: 0;
    right: 0;
    background: var(--openai-bg);
    border-top: 1px solid var(--openai-border);
    padding: 12px 24px;
    z-index: 1000;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

.bottom-nav-content {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    justify-content: center;
    gap: 8px;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 20px;
    border-radius: 8px;
    color: var(--openai-text-secondary);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    border: 1px solid transparent;
    text-decoration: none;
}

.nav-item:hover {
    background: var(--openai-bg-secondary);
    color: var(--openai-text-primary);
}

.nav-item.active {
    background: var(--openai-bg-secondary);
    color: var(--openai-accent);
    border-color: var(--openai-accent);
}

.nav-item i {
    font-size: 18px;
}

/* 备案号样式 */
.footer-beian {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    text-align: center;
    padding: 6px 24px;
    background: var(--openai-bg);
    border-top: 1px solid var(--openai-border);
    z-index: 1001;
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

.beian-link {
    color: var(--openai-text-secondary);
    font-size: 12px;
    text-decoration: none;
    transition: color 0.2s ease;
}

.beian-link:hover {
    color: var(--openai-accent);
    text-decoration: underline;
}

/* OpenAI风格弹窗 */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    z-index: 2000;
    justify-content: center;
    align-items: center;
    padding: 24px;
    animation: fadeIn 0.3s ease;
}

.modal-content {
    background: var(--openai-bg);
    border: 1px solid var(--openai-border);
    border-radius: 16px;
    width: 100%;
    max-width: 600px;
    max-height: 90vh;
    overflow: hidden;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    display: flex;
    flex-direction: column;
    animation: slideUp 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 24px;
    border-bottom: 1px solid var(--openai-border);
}

.modal-header h2 {
    font-size: 24px;
    font-weight: 600;
    color: var(--openai-text-primary);
    letter-spacing: -0.5px;
    margin: 0;
}

.close-modal {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 8px;
    background: transparent;
    border: none;
    color: var(--openai-text-secondary);
    font-size: 24px;
    cursor: pointer;
    transition: all 0.2s ease;
    padding: 0;
    line-height: 1;
}

.close-modal:hover {
    background: var(--openai-bg-secondary);
    color: var(--openai-text-primary);
}

.modal-body {
    padding: 24px;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    flex: 1;
}

/* OpenAI风格内容样式 */
.about-content h3,
.contact-info h3 {
    font-size: 20px;
    font-weight: 600;
    color: var(--openai-text-primary);
    margin-bottom: 16px;
    letter-spacing: -0.3px;
}

.about-content h4,
.contact-form h4 {
    font-size: 18px;
    font-weight: 600;
    color: var(--openai-text-primary);
    margin-top: 24px;
    margin-bottom: 12px;
    letter-spacing: -0.2px;
}

.about-content p,
.contact-info p {
    font-size: 16px;
    color: var(--openai-text-secondary);
    line-height: 1.6;
    margin-bottom: 16px;
}

.about-content ul {
    padding-left: 24px;
    margin-bottom: 20px;
    list-style: disc;
}

.about-content li {
    font-size: 16px;
    color: var(--openai-text-secondary);
    line-height: 1.8;
    margin-bottom: 8px;
}

.contact-content {
    display: flex;
    flex-direction: column;
    gap: 32px;
}

.contact-info p {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    margin-bottom: 16px;
}

.contact-info i {
    color: var(--openai-accent);
    width: 20px;
    font-size: 18px;
    flex-shrink: 0;
    margin-top: 2px;
}

.contact-info .email-link {
    color: var(--openai-accent);
    text-decoration: none;
    transition: all 0.2s ease;
}

.contact-info .email-link:hover {
    text-decoration: underline;
    opacity: 0.8;
}

.contact-form h4 {
    margin-top: 0;
}

.form-group {
    margin-bottom: 24px;
}

.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 500;
    color: var(--openai-text-primary);
    margin-bottom: 8px;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--openai-border);
    border-radius: 8px;
    font-size: 16px;
    font-family: inherit;
    background: var(--openai-bg);
    color: var(--openai-text-primary);
    transition: all 0.2s ease;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--openai-accent);
    box-shadow: 0 0 0 3px rgba(0, 102, 255, 0.1);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--openai-text-tertiary);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
    line-height: 1.6;
}

.submit-btn {
    background: var(--openai-accent);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    width: 100%;
}

.submit-btn:hover {
    background: var(--openai-accent-hover);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(0, 102, 255, 0.3);
}

.submit-btn:active {
    transform: translateY(0);
}

/* 动画 */
@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(40px) scale(0.95);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

/* 响应式设计 */
@media (max-width: 768px) {
    .top-nav {
        padding: 12px 16px;
    }
    
    .logo-section h1 {
        font-size: 18px;
    }
    
    .main-content {
        padding: 32px 16px;
        margin-top: 60px;
    }
    
    .video-section {
        margin-bottom: 48px;
    }
    
    .promo-video {
        border-radius: 12px;
    }
    
    .video-credit {
        font-size: 13px;
        margin-top: 10px;
    }
    
    .logo-wall {
        grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
        gap: 16px;
    }
    
    .logo-item {
        padding: 20px;
    }
    
    .logo-item.main-logo {
        padding: 32px 24px;
    }
    
    .bottom-nav {
        padding: 8px 16px;
    }
    
    .bottom-nav-content {
        gap: 4px;
    }
    
    .nav-item {
        padding: 8px 8px;
        font-size: 12px;
    }
    
    .nav-item span {
        display: none;
    }
    
    .nav-item i {
        font-size: 18px;
    }
    
    .modal {
        padding: 16px;
    }
    
    .modal-content {
        border-radius: 12px;
    }
    
    .modal-header {
        padding: 20px;
    }
    
    .modal-body {
        padding: 20px;
    }
    
    .footer-beian {
        padding: 6px 16px;
    }
    
    .bottom-nav {
        bottom: 26px;
    }
}

@media (max-width: 480px) {
    .hero-section h2 {
        font-size: 28px;
    }
    
    .hero-section p {
        font-size: 16px;
    }
    
    .logo-wall {
        grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    }
    
    .logo-content {
        width: 56px;
        height: 56px;
        font-size: 24px;
    }
    
    .logo-item.main-logo .logo-content {
        width: 80px;
        height: 80px;
    }
    
    .logo-item.main-logo .logo-content span {
        font-size: 32px;
    }
    
    .logo-name {
        font-size: 14px;
    }
}

/* 隐藏旧的元素 */
.company-info {
    display: none;
}