/* ===== UUAN（佑然）技术咨询 - Nous Research 浅色风格 ===== */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap');

/* ===== 基础设置 ===== */
html, body {
    overflow-x: hidden;
    position: relative;
    width: 100%;
    touch-action: pan-y;
    overscroll-behavior-x: none;
    -ms-overflow-style: none;
    scrollbar-width: none;
    background: #ffffff;
}

html::-webkit-scrollbar,
body::-webkit-scrollbar {
    display: none;
}

/* ===== 品牌色 - Nous Research 浅色风格 ===== */
:root {
    --bg-primary: #ffffff;
    --bg-elevated: #f8f9fa;
    --bg-card: #ffffff;
    --bg-card-hover: #fafbfc;
    --border-default: #e5e7eb;
    --border-hover: #93c5fd;
    --border-active: #3b82f6;
    --text-primary: #111827;
    --text-secondary: #4b5563;
    --text-tertiary: #9ca3af;
    --text-muted: #d1d5db;
    --accent: #2563eb;
    --accent-light: #dbeafe;
    --accent-dim: rgba(37, 99, 235, 0.08);
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 14px;
    --transition-fast: 0.15s ease;
    --transition-base: 0.2s ease;
}

/* ===== Logo ===== */
.logo {
    font-weight: 600;
    font-size: 1rem;
    letter-spacing: -0.2px;
    text-decoration: none;
    color: var(--text-primary);
    font-family: 'Inter', -apple-system, sans-serif;
}

/* ===== 导航栏覆写 ===== */
.header {
    background: rgba(255, 255, 255, 0.85) !important;
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border-bottom: 1px solid var(--border-default);
}

.nav-menu a {
    color: var(--text-secondary);
    font-weight: 400;
    font-size: 0.875rem;
    transition: color var(--transition-fast);
    letter-spacing: 0.02em;
    text-transform: uppercase;
}

.nav-menu a:hover,
.nav-menu a.active {
    color: var(--accent);
}

/* ===== 移动端汉堡菜单 ===== */
.nav-toggle {
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    width: 36px;
    height: 36px;
    background: none;
    border: none;
    cursor: pointer;
    gap: 4px;
    padding: 6px;
    z-index: 101;
    -webkit-tap-highlight-color: transparent;
}

.nav-toggle-bar {
    display: block;
    width: 20px;
    height: 1.5px;
    background: var(--text-primary);
    border-radius: 1px;
    transition: transform 0.25s ease, opacity 0.25s ease;
}

.nav-toggle.active .nav-toggle-bar:nth-child(1) {
    transform: translateY(5.5px) rotate(45deg);
}

.nav-toggle.active .nav-toggle-bar:nth-child(2) {
    opacity: 0;
}

.nav-toggle.active .nav-toggle-bar:nth-child(3) {
    transform: translateY(-5.5px) rotate(-45deg);
}

/* ===== 语言切换 ===== */
.lang-switch {
    display: flex;
    align-items: center;
    gap: 6px;
    margin-left: 20px;
}

.lang-btn {
    background: none;
    border: none;
    font-size: 0.8rem;
    font-weight: 500;
    font-family: 'Inter', -apple-system, sans-serif;
    color: var(--text-tertiary);
    cursor: pointer;
    padding: 4px 8px;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
    letter-spacing: 0.5px;
    -webkit-tap-highlight-color: transparent;
}

.lang-btn:hover {
    color: var(--text-secondary);
}

.lang-btn.active {
    color: var(--accent);
    font-weight: 600;
    background: var(--accent-dim);
}

.lang-divider {
    color: var(--border-default);
    font-size: 0.75rem;
}

/* ===== Hero 区域 ===== */
.uuan-hero {
    padding: 140px 0 80px;
    text-align: center;
    background: var(--bg-primary);
    position: relative;
    border-bottom: 1px solid var(--border-default);
}

.uuan-hero-content {
    position: relative;
    z-index: 1;
}

.uuan-hero-brand {
    margin-bottom: 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.uuan-hero-brand h1 {
    font-family: 'Inter', -apple-system, sans-serif;
    font-size: 2.2rem;
    font-weight: 600;
    color: var(--accent);
    margin-bottom: 16px;
    letter-spacing: -0.02em;
    line-height: 1.2;
    word-break: keep-all;
    overflow-wrap: break-word;
    max-width: 100%;
}

.uuan-hero-brand .uuan-hero-subtitle {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.75rem;
    font-weight: 400;
    color: var(--text-tertiary);
    margin-bottom: 0;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    word-break: keep-all;
    overflow-wrap: break-word;
    max-width: 100%;
}

.uuan-hero-content > p {
    font-size: 0.95rem;
    font-weight: 400;
    color: var(--text-secondary);
    max-width: 480px;
    margin: 0 auto 32px;
    line-height: 1.7;
    padding: 0 20px;
}

/* ===== 按钮 ===== */
.uuan-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 10px 28px;
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    transition: all var(--transition-base);
    border: 1px solid var(--border-default);
    font-family: 'Inter', -apple-system, sans-serif;
    letter-spacing: 0.02em;
    -webkit-tap-highlight-color: transparent;
    background: var(--bg-card);
    color: var(--text-primary);
    text-transform: uppercase;
}

.uuan-btn-primary {
    background: var(--accent);
    color: #ffffff;
    border-color: var(--accent);
}

.uuan-btn-primary:hover {
    background: #1d4ed8;
    border-color: #1d4ed8;
    transform: translateY(-1px);
}

.uuan-btn-block {
    display: block;
    width: 100%;
}

/* ===== 通用区块 ===== */
.uuan-section {
    padding: 64px 0;
}

.uuan-bg-light {
    background: var(--bg-elevated);
    border-top: 1px solid var(--border-default);
    border-bottom: 1px solid var(--border-default);
}

.uuan-section-title {
    font-family: 'JetBrains Mono', monospace;
    font-size: 1.1rem;
    font-weight: 500;
    color: var(--accent);
    text-align: center;
    margin-bottom: 40px;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

/* ===== 关于我们 ===== */
.uuan-about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 48px;
    align-items: center;
}

.uuan-about-text p {
    font-size: 0.9rem;
    font-weight: 400;
    color: var(--text-secondary);
    line-height: 1.75;
    margin-bottom: 14px;
}

.uuan-about-text p:last-child {
    margin-bottom: 0;
}

.uuan-about-stats {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
}

.uuan-stat-card {
    background: var(--bg-card);
    border-radius: var(--radius-md);
    padding: 24px 16px;
    text-align: center;
    border: 1px solid var(--border-default);
    transition: all var(--transition-base);
}

.uuan-stat-card:hover {
    border-color: var(--border-hover);
}

.uuan-stat-number {
    display: block;
    font-family: 'JetBrains Mono', monospace;
    font-size: 1.5rem;
    font-weight: 500;
    color: var(--accent);
    margin-bottom: 4px;
    letter-spacing: -0.02em;
}

.uuan-stat-label {
    font-size: 0.75rem;
    font-weight: 400;
    color: var(--text-tertiary);
    letter-spacing: 0.02em;
    text-transform: uppercase;
}

/* ===== 服务领域 ===== */
.uuan-services-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
}

.uuan-service-card {
    background: var(--bg-card);
    border-radius: var(--radius-md);
    padding: 28px 24px;
    text-align: left;
    border: 1px solid var(--border-default);
    transition: all var(--transition-base);
}

.uuan-service-card:hover {
    border-color: var(--border-hover);
    background: var(--bg-card-hover);
}

.uuan-service-icon {
    font-size: 1.6rem;
    margin-bottom: 16px;
    display: inline-block;
    opacity: 0.85;
}

.uuan-service-card h3 {
    font-family: 'Inter', -apple-system, sans-serif;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 8px;
    letter-spacing: -0.01em;
}

.uuan-service-card p {
    font-size: 0.8rem;
    font-weight: 400;
    color: var(--text-tertiary);
    line-height: 1.6;
}

/* ===== 核心优势 ===== */
.uuan-advantage-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
}

.uuan-advantage-item {
    text-align: left;
    padding: 28px 24px;
    border-radius: var(--radius-md);
    background: var(--bg-card);
    border: 1px solid var(--border-default);
    transition: all var(--transition-base);
}

.uuan-advantage-item:hover {
    border-color: var(--border-hover);
    background: var(--bg-card-hover);
}

.uuan-advantage-number {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.7rem;
    font-weight: 500;
    color: var(--accent);
    margin-bottom: 14px;
    letter-spacing: 0.08em;
    display: block;
    text-transform: uppercase;
}

.uuan-advantage-item h3 {
    font-family: 'Inter', -apple-system, sans-serif;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 8px;
    letter-spacing: -0.01em;
}

.uuan-advantage-item p {
    font-size: 0.8rem;
    font-weight: 400;
    color: var(--text-tertiary);
    line-height: 1.6;
}

/* ===== 联系我们 ===== */
.uuan-contact-grid {
    display: flex;
    justify-content: center;
}

.uuan-contact-form {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    padding: 36px;
    border: 1px solid var(--border-default);
    width: 100%;
    max-width: 480px;
}

.uuan-contact-form h3 {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--accent);
    margin-bottom: 24px;
    letter-spacing: 0.06em;
    text-transform: uppercase;
}

.uuan-form-group {
    margin-bottom: 12px;
}

.uuan-form-group input,
.uuan-form-group textarea {
    width: 100%;
    padding: 12px 14px;
    border: 1px solid var(--border-default);
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-weight: 400;
    font-family: 'Inter', -apple-system, sans-serif;
    outline: none;
    transition: all var(--transition-base);
    background: var(--bg-elevated);
    color: var(--text-primary);
    -webkit-appearance: none;
    appearance: none;
}

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

.uuan-form-group input:focus,
.uuan-form-group textarea:focus {
    border-color: var(--accent);
    background: var(--bg-card);
    box-shadow: 0 0 0 2px var(--accent-dim);
}

.uuan-form-group textarea {
    resize: vertical;
    min-height: 100px;
}

/* ===== 页脚 ===== */
.footer {
    padding: 32px 0;
    text-align: center;
    background: var(--bg-primary);
    border-top: 1px solid var(--border-default);
}

.footer-email {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: 0.875rem;
    font-weight: 400;
    color: var(--text-tertiary);
    margin-bottom: 8px;
}

.footer-email .email-icon {
    width: 16px;
    height: 16px;
    color: var(--text-tertiary);
    flex-shrink: 0;
}

.footer-email a {
    color: inherit;
    text-decoration: none;
    transition: color var(--transition-fast);
}

.footer-email a:hover {
    color: var(--accent);
}

.footer p {
    font-size: 0.75rem;
    font-weight: 400;
    color: var(--text-muted);
}

.footer-copyright {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
}

.footer-icp {
    font-size: 0.75rem;
    font-weight: 400;
    color: var(--text-muted);
    margin-top: 6px;
}

/* ===== 响应式 - 平板 ===== */
@media (max-width: 992px) {
    .uuan-about-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .uuan-services-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .uuan-advantage-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* ===== 响应式 - 手机横屏/大屏手机 ===== */
@media (max-width: 768px) {
    .nav {
        position: relative;
    }

    .nav-toggle {
        display: flex;
    }

    .nav-menu {
        position: absolute;
        top: 56px;
        left: 0;
        right: 0;
        background: rgba(255, 255, 255, 0.98);
        backdrop-filter: blur(20px);
        -webkit-backdrop-filter: blur(20px);
        flex-direction: column;
        align-items: center;
        gap: 0;
        padding: 8px 0;
        border-bottom: 1px solid var(--border-default);
        transform: translateY(-10px);
        opacity: 0;
        visibility: hidden;
        transition: transform 0.25s ease, opacity 0.25s ease, visibility 0.25s ease;
        z-index: 99;
    }

    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .nav-menu li {
        width: 100%;
        text-align: center;
    }

    .nav-menu a {
        display: block;
        padding: 12px 20px;
        font-size: 0.9rem;
        color: var(--text-secondary);
        border-bottom: 1px solid var(--border-default);
    }

    .nav-menu li:last-child a {
        border-bottom: none;
    }

    .lang-switch {
        margin-left: auto;
        margin-right: 6px;
    }

    .uuan-hero {
        padding: 120px 20px 60px;
    }

    .uuan-hero-brand h1 {
        font-size: 1.6rem;
        white-space: normal;
        word-break: keep-all;
        overflow-wrap: break-word;
        padding: 0;
    }

    .uuan-hero-brand .uuan-hero-subtitle {
        font-size: 0.7rem;
        letter-spacing: 0.12em;
        white-space: normal;
        padding: 0;
    }

    .uuan-hero-content > p {
        font-size: 0.9rem;
        padding: 0 10px;
    }

    .uuan-section-title {
        font-size: 1rem;
        margin-bottom: 32px;
    }

    .uuan-section {
        padding: 48px 0;
    }

    .uuan-contact-form {
        max-width: 100%;
        padding: 28px 20px;
    }

    .uuan-about-stats {
        gap: 10px;
    }

    .uuan-stat-number {
        font-size: 1.3rem;
    }

    .container {
        padding: 0 16px;
    }
}

/* ===== 响应式 - 小屏手机 ===== */
@media (max-width: 576px) {
    .uuan-services-grid {
        grid-template-columns: 1fr;
        gap: 16px;
    }

    .uuan-advantage-grid {
        grid-template-columns: 1fr;
        gap: 16px;
    }

    .uuan-about-stats {
        gap: 16px;
    }

    .uuan-hero {
        padding: 120px 20px 60px;
    }

    .uuan-hero-brand h1 {
        font-size: 1.5rem;
        line-height: 1.3;
        letter-spacing: -0.02em;
    }

    .uuan-hero-brand .uuan-hero-subtitle {
        font-size: 0.7rem;
        letter-spacing: 0.12em;
    }

    .uuan-hero-content > p {
        font-size: 0.9rem;
        margin-bottom: 28px;
        line-height: 1.75;
    }

    .uuan-section {
        padding: 48px 0;
    }

    .uuan-section-title {
        font-size: 1.05rem;
        margin-bottom: 32px;
    }

    .uuan-contact-form {
        padding: 28px 20px;
    }

    .uuan-service-card {
        padding: 28px 24px;
        border-radius: var(--radius-md);
    }

    .uuan-service-card h3 {
        font-size: 1rem;
    }

    .uuan-service-card p {
        font-size: 0.85rem;
        line-height: 1.65;
    }

    .uuan-service-icon {
        font-size: 2rem;
        margin-bottom: 18px;
    }

    .uuan-advantage-item {
        padding: 28px 24px;
        border-radius: var(--radius-md);
    }

    .uuan-advantage-item h3 {
        font-size: 1rem;
    }

    .uuan-advantage-item p {
        font-size: 0.85rem;
        line-height: 1.65;
    }

    .uuan-advantage-number {
        font-size: 0.8rem;
        margin-bottom: 16px;
    }

    .uuan-about-text p {
        font-size: 0.9rem;
        line-height: 1.8;
    }

    .uuan-stat-card {
        padding: 24px 16px;
    }

    .uuan-stat-number {
        font-size: 1.5rem;
    }

    .uuan-stat-label {
        font-size: 0.75rem;
    }

    .uuan-form-group {
        margin-bottom: 14px;
    }

    .uuan-form-group input,
    .uuan-form-group textarea {
        padding: 14px 16px;
        font-size: 16px;
        border-radius: var(--radius-md);
    }

    .uuan-btn {
        padding: 12px 28px;
        font-size: 0.9rem;
    }

    .footer {
        padding: 36px 20px;
    }

    .footer-email {
        font-size: 0.9rem;
    }

    .footer p {
        font-size: 0.8rem;
    }

    .container {
        padding: 0 20px;
    }
}

/* ===== 响应式 - 超小屏 ===== */
@media (max-width: 360px) {
    .uuan-hero {
        padding: 110px 16px 50px;
    }

    .uuan-hero-brand h1 {
        font-size: 1.3rem;
    }

    .uuan-hero-brand .uuan-hero-subtitle {
        font-size: 0.65rem;
        letter-spacing: 0.1em;
    }

    .uuan-hero-content > p {
        font-size: 0.85rem;
    }

    .uuan-section {
        padding: 40px 0;
    }

    .uuan-section-title {
        font-size: 0.95rem;
        margin-bottom: 24px;
    }

    .uuan-service-card {
        padding: 24px 20px;
    }

    .uuan-service-card h3 {
        font-size: 0.95rem;
    }

    .uuan-service-card p {
        font-size: 0.8rem;
    }

    .uuan-advantage-item {
        padding: 24px 20px;
    }

    .uuan-stat-card {
        padding: 20px 12px;
    }

    .uuan-stat-number {
        font-size: 1.3rem;
    }

    .uuan-form-group input,
    .uuan-form-group textarea {
        padding: 12px 14px;
    }

    .container {
        padding: 0 16px;
    }

    .lang-switch {
        gap: 2px;
    }

    .lang-btn {
        font-size: 0.7rem;
        padding: 3px 5px;
    }
}

/* ===== 响应式 - 超小屏 ===== */
@media (max-width: 360px) {
    .uuan-hero-brand h1 {
        font-size: 1.1rem;
    }

    .uuan-hero-brand .uuan-hero-subtitle {
        font-size: 0.6rem;
        letter-spacing: 0.08em;
    }

    .lang-switch {
        gap: 2px;
    }

    .lang-btn {
        font-size: 0.7rem;
        padding: 3px 5px;
    }
}