* { margin: 0; padding: 0; box-sizing: border-box; }
/* CSS Variables */
:root {
    --logo-color: #dc3545; /* 主色调（LOGO红色） */
    --primary-color: var(--logo-color); /* 主色调（LOGO红色） */
    --secondary-color: #0b234c; /* 辅助色 */
    --background-color: #fff; /* 背景色 */
    --text-color: #353535; /* 文本色 */
    --light-gray: #f9f9f9; /* 浅灰色 */
    --dark-gray: #444; /* 深灰色 */
    --nav-bg: #ffffff; /* 导航背景色 */
    --nav-text: #0a1d3f; /* 导航文本色 */
    --border-radius: 5px; /* 圆角 */
    --transition-speed: 0.3s; /* 过渡速度 */
    --border-color: #e0e0e0; /* 边框颜色 */
}


body {
    width: 100%;
    font-family: "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    position: relative;
}




/** common styles **/
a {
    color: var(--primary-color);
    text-decoration: none;
}
li {
    list-style: none;
}
.section{
    max-width: 1000px;
    margin: 0 auto 0;
    padding: 0 1rem;
}

.section-title{
    text-align: center;
}
.section-subtitle{
    letter-spacing: 2px;
    font-weight: 300;
    text-align: center;
    margin-bottom: 1rem;
}
div.section-content{
    padding: 1rem 0;
    line-height: 1.8;
}

/* Header */
.main-header {
    background: var(--nav-bg);
    color: var(--nav-text);
    padding: 1rem 0;
    min-height: 64px;
    position: sticky;
    top:0;
    z-index: 10;
}

.main-header .section {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 1rem;
}

/* Logo样式 */
.logo-container {
    display: flex;
    align-items: center;
    gap: 0.8rem;
}

.logo-image {
    height: 50px;
    width: auto;
    border-radius: var(--border-radius);
}

.logo-text {
    font-size: 1.4rem;
    margin: 0;
    font-weight: 500;
}

.nav-menu{
    display: flex;
    gap: 2rem;
}

/* Navigation */
.nav-list {
    list-style: none;
    display: flex;
    gap: 2rem;
}

.nav-list li {
    position: relative;
}

.nav-list a {
    color: var(--nav-text);
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 500;
    padding: 0.5rem 0;
    position: relative;
    transition: color var(--transition-speed) ease;
}

/* Hover effect: underline expanding from center */
.nav-list a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 2px;
    background-color: var(--primary-color);
    transition: width var(--transition-speed) ease, left var(--transition-speed) ease;
}

.nav-list a:hover::after,
.nav-list a.active::after {
    width: 100%;
    left: 0;
}

/* Active link style */
.nav-list a.active {
    font-weight: 600;
}

/* Menu Toggle (Hamburger Menu) */
.menu-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    z-index: 11;
}

.menu-icon {
    display: block;
    width: 25px;
    height: 3px;
    background-color: var(--nav-text);
    margin: 5px 0;
    transition: all var(--transition-speed) ease;
    border-radius: 2px;
}

.nav-contact{
    display: flex;
    align-items: center;
    gap: 0.5rem;
}


/* Footer */
footer {
    margin-top: 2rem;
    color: #ccc;
    padding: 2rem 0 0;
    font-size: 0.9rem;
    background-color: var(--secondary-color);
}

footer .footer-us{
    width: 100%;
    max-width: 1000px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    gap: 2rem;
    align-items: end;
}
footer .footer-us .us{
    display: flex;
    flex-direction: column;
    gap: 1rem;
    align-items: start;
}
footer .logo{
    height: 40px;
    border-radius: 4px;
    object-fit: contain;
}
footer .logo-name{
    font-size: 18px;
    font-weight: 500;
}
footer .footer-us .contact{
    text-align: right;
}

footer .footer-info{
    padding: 2rem 0 1rem;
    display: flex;
    justify-content: center;
    gap: 0.5rem;
}
footer .footer-info-item{
    color: #ccc;
    display: flex;
    align-items: center;
    font-size: 14px;
}
footer .footer-info-item img{
    width: 20px;
    height: 20px;
    margin-right: 8px;
}
footer .footer-info a{
    color: #ccc;
}
footer .footer-info a:hover{
    color: var(--light-gray);
}






/* Responsive Navigation */
/* <768px */
@media (max-width: 768px) {
    .menu-toggle {
        display: block;
    }

    .nav-menu {
        position: fixed;
        flex-direction: column;
        top: 64px;
        left: -100%;
        width: 90%;
        height: calc(100vh - 64px);
        background-color: var(--nav-bg);
        transition: left var(--transition-speed) ease;
        z-index: 10;
        padding: 1rem 0;
        display: flex;
        align-items: center;
    }

    .nav-menu.active {
        left: 0;
    }

    .nav-list {
        flex-direction: column;
        gap: 0;
        align-items: center;
    }

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

    .nav-list a {
        display: block;
        padding: 1rem 0;
        font-size: 1.1rem;
    }

    .nav-phone{
        margin: 2rem auto;
        font-size: 20px;
    }

    /* Menu Toggle Animation */
    .menu-toggle.active .menu-icon:nth-child(1) {
        transform: rotate(45deg) translate(7px, 7px);
    }

    .menu-toggle.active .menu-icon:nth-child(2) {
        opacity: 0;
    }

    .menu-toggle.active .menu-icon:nth-child(3) {
        transform: rotate(-45deg) translate(7px, -7px);
    }


    footer{
        flex-direction: column;
        box-sizing: border-box;
        padding: 2rem 1rem 0;
    }
    footer .footer-us{
        flex-direction: column;
        gap: 1rem;
        align-items: center;
    }
    footer .footer-us .us{
        align-items: center;
    }
    footer .logo-name{
        text-align: center;
    }
    footer .footer-us .contact{
        text-align: center;
    }
    footer .footer-info{
        flex-direction: column;
        gap: 1rem;
        align-items: center;
    }
}