/* ===================================
   北京赛力肯科技有限公司 - 主样式表
   =================================== */

/* CSS Variables */
:root {
    --primary-color: #000000;
    --primary-dark: #000000;
    --secondary-color: #1a1a1a;
    --text-dark: #000000;
    --text-gray: #666666;
    --text-light: #333333;
    --bg-light: #fafafa;
    --bg-dark: #000000;
    --white: #ffffff;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
    --shadow-lg: 0 8px 24px rgba(0,0,0,0.12);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-light);
}

/* ===================================
   Navigation
   =================================== */
.nav {
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid #eaeaea;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--primary-color);
    text-decoration: none;
    transition: opacity 0.3s;
}

.logo:hover {
    opacity: 0.8;
}

.nav-right {
    display: flex;
    align-items: center;
    gap: 30px;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-gray);
    transition: color 0.2s;
    font-weight: 400;
    font-size: 0.95rem;
}

.nav-links a:hover {
    color: var(--primary-color);
}

/* ===================================
   Language Dropdown
   =================================== */
.lang-dropdown {
    position: relative;
}

.lang-toggle {
    display: flex;
    align-items: center;
    gap: 6px;
    background: transparent;
    border: 1px solid #e0e0e0;
    color: var(--text-gray);
    padding: 6px 12px;
    border-radius: 6px;
    font-size: 0.9rem;
    cursor: pointer;
    transition: all 0.2s;
    font-weight: 500;
}

.lang-toggle:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    background: var(--white);
}

.lang-toggle[aria-expanded="true"] {
    border-color: var(--primary-color);
    color: var(--primary-color);
    background: var(--white);
}

.lang-arrow {
    transition: transform 0.2s;
}

.lang-toggle[aria-expanded="true"] .lang-arrow {
    transform: rotate(180deg);
}

.lang-menu {
    position: absolute;
    top: calc(100% + 8px);
    right: 0;
    background: var(--white);
    border: 1px solid #e0e0e0;
    border-radius: 8px;
    box-shadow: var(--shadow-md);
    min-width: 140px;
    padding: 6px;
    list-style: none;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: all 0.2s;
    z-index: 1001;
}

.lang-menu[aria-hidden="false"] {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.lang-option {
    width: 100%;
    text-align: left;
    background: transparent;
    border: none;
    padding: 10px 14px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.9rem;
    color: var(--text-light);
    transition: all 0.15s;
    font-family: inherit;
}

.lang-option:hover {
    background: var(--bg-light);
}

.lang-option[aria-selected="true"] {
    background: var(--bg-light);
    color: var(--primary-color);
    font-weight: 500;
}

/* ===================================
   Hero Section
   =================================== */
.hero {
    background: var(--white);
    color: var(--text-dark);
    padding: 180px 20px 120px;
    text-align: center;
    margin-top: 70px;
    position: relative;
    overflow: hidden;
}

.hero-animation {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    z-index: 0;
}

.tech-dot {
    position: absolute;
    width: 4px;
    height: 4px;
    background: rgba(0, 0, 0, 0.2);
    border-radius: 50%;
    animation: float 15s infinite ease-in-out;
}

.tech-dot:nth-child(1) {
    top: 20%;
    left: 10%;
    animation-delay: 0s;
}

.tech-dot:nth-child(2) {
    top: 60%;
    left: 20%;
    animation-delay: 2s;
}

.tech-dot:nth-child(3) {
    top: 40%;
    left: 70%;
    animation-delay: 4s;
}

.tech-dot:nth-child(4) {
    top: 80%;
    left: 50%;
    animation-delay: 6s;
}

.tech-dot:nth-child(5) {
    top: 30%;
    left: 80%;
    animation-delay: 8s;
}

@keyframes float {
    0%, 100% {
        transform: translate(0, 0) scale(1);
        opacity: 0.3;
    }
    25% {
        transform: translate(100px, -50px) scale(1.5);
        opacity: 0.6;
    }
    50% {
        transform: translate(-50px, 100px) scale(1);
        opacity: 0.3;
    }
    75% {
        transform: translate(50px, 50px) scale(1.2);
        opacity: 0.5;
    }
}

.hero h1 {
    font-size: 3.5rem;
    margin-bottom: 24px;
    font-weight: 600;
    letter-spacing: -0.02em;
    line-height: 1.1;
    position: relative;
    z-index: 1;
}

.hero p {
    font-size: 1.25rem;
    color: var(--text-gray);
    max-width: 600px;
    margin: 0 auto 40px;
    line-height: 1.6;
    position: relative;
    z-index: 1;
}

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

.btn {
    display: inline-block;
    padding: 14px 32px;
    background: var(--primary-color);
    color: var(--white);
    text-decoration: none;
    border-radius: 8px;
    font-weight: 500;
    font-size: 1rem;
    transition: transform 0.2s, box-shadow 0.2s, background 0.2s;
}

.btn:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

/* ===================================
   Common Section Styles
   =================================== */
.section {
    padding: 100px 20px;
    max-width: 1200px;
    margin: 0 auto;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 60px;
    color: var(--text-dark);
    font-weight: 600;
    letter-spacing: -0.01em;
}

/* ===================================
   About Section
   =================================== */
.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 50px;
    align-items: center;
}

.about-text h3 {
    font-size: 1.5rem;
    margin-bottom: 15px;
    color: var(--primary-color);
}

.about-text p {
    margin-bottom: 15px;
    color: var(--text-gray);
}

.about-image {
    background: linear-gradient(135deg, #f5f5f5 0%, #eeeeee 100%);
    height: 300px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-dark);
    font-size: 1.1rem;
    flex-direction: column;
    border: 1px solid #eaeaea;
}

.about-image-icon {
    font-size: 4rem;
    margin-bottom: 10px;
}

/* ===================================
   Services Section
   =================================== */
.services {
    background: var(--bg-light);
}

.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.service-card {
    background: var(--white);
    padding: 40px 30px;
    border-radius: 12px;
    text-align: center;
    transition: transform 0.2s, box-shadow 0.2s;
    border: 1px solid #f0f0f0;
}

.service-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: #e0e0e0;
}

.service-icon {
    font-size: 3rem;
    margin-bottom: 20px;
}

.service-card h3 {
    margin-bottom: 15px;
    color: var(--text-dark);
}

.service-card p {
    color: var(--text-gray);
}

/* ===================================
   Contact Section
   =================================== */

/* ===================================
   Footer
   =================================== */
.footer {
    background: #000000;
    color: var(--white);
    padding: 60px 20px 40px;
    text-align: center;
    border-top: 1px solid #2d2d2d;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
}

.footer-contact h3 {
    font-size: 1.5rem;
    margin-bottom: 30px;
    font-weight: 600;
}

.contact-items-row {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 60px;
    margin-bottom: 50px;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 1rem;
}

.contact-item-icon {
    font-size: 1.3rem;
}

.footer-copy p {
    opacity: 0.6;
    font-size: 0.9rem;
}

/* ===================================
   Responsive Design
   =================================== */
@media (max-width: 768px) {
    .logo {
        font-size: 0.95rem;
    }

    .nav-right {
        gap: 15px;
    }

    .nav-links {
        display: none;
    }

    .lang-toggle {
        padding: 5px 10px;
        font-size: 0.85rem;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .hero p {
        font-size: 1.1rem;
    }

    .about-grid {
        grid-template-columns: 1fr;
    }

    .services-grid {
        grid-template-columns: 1fr;
    }

    .section {
        padding: 60px 20px;
    }

    .contact-items-row {
        flex-direction: column;
        gap: 20px;
    }

    .footer {
        padding: 40px 20px 30px;
    }
}

@media (max-width: 480px) {
    .logo {
        font-size: 0.85rem;
    }

    .hero h1 {
        font-size: 1.75rem;
    }

    .hero p {
        font-size: 1rem;
    }

    .btn {
        padding: 10px 24px;
    }

    .service-card {
        padding: 30px 20px;
    }
}