/* ========================================
   Common CSS - 公共样式
   ======================================== */

/* === CSS Variables === */
:root {
    --color-primary: #1a1a1a;
    --color-accent: #c8a45c;
    --color-accent-dark: #a88844;
    --color-gold: #d4af6e;
    --color-white: #ffffff;
    --color-light: #f8f8f8;
    --color-gray: #f5f5f5;
    --color-text: #333333;
    --color-text-light: #666666;
    --color-text-lighter: #999999;
    --color-border: #e8e8e8;
    --color-dark: #1a1a1a;
    --color-overlay: rgba(0, 0, 0, 0.5);
    --font-heading: "Times New Roman", "SimSun", "STSong", serif;
    --transition: all 0.3s ease;
    --shadow-sm: 0 2px 10px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 40px rgba(0, 0, 0, 0.15);
}

/* === Section Title === */
.section-title {
    text-align: center;
    margin-bottom: 60px;
}

.section-title .en-title {
    font-family: var(--font-heading);
    font-size: 1.4rem;
    color: var(--color-accent);
    text-transform: uppercase;
    letter-spacing: 4px;
    margin-bottom: 10px;
    display: block;
}

.section-title .cn-title {
    font-size: 3.6rem;
    font-weight: 600;
    color: var(--color-primary);
    letter-spacing: 2px;
}

.section-title .title-line {
    display: block;
    width: 60px;
    height: 3px;
    background: var(--color-accent);
    margin: 16px auto 0;
}

/* === Buttons === */
.btn {
    display: inline-block;
    padding: 14px 40px;
    font-size: 1.5rem;
    letter-spacing: 2px;
    border-radius: 2px;
    cursor: pointer;
    transition: var(--transition);
    text-align: center;
    border: 1px solid transparent;
}

.btn-primary {
    background: var(--color-accent);
    color: var(--color-white);
    border-color: var(--color-accent);
}

.btn-primary:hover {
    background: var(--color-accent-dark);
    border-color: var(--color-accent-dark);
}

.btn-outline {
    background: transparent;
    color: var(--color-accent);
    border-color: var(--color-accent);
}

.btn-outline:hover {
    background: var(--color-accent);
    color: var(--color-white);
}

.btn-outline-light {
    background: transparent;
    color: var(--color-white);
    border-color: var(--color-white);
}

.btn-outline-light:hover {
    background: var(--color-white);
    color: var(--color-primary);
}

.btn-dark {
    background: var(--color-primary);
    color: var(--color-white);
    border-color: var(--color-primary);
}

.btn-dark:hover {
    background: #333;
    border-color: #333;
}

/* === Header === */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    padding: 20px 0;
    transition: var(--transition);
    background: transparent;
}

.header.scrolled {
    background: rgba(255, 255, 255, 0.98);
    box-shadow: var(--shadow-sm);
    padding: 12px 0;
}

.header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.header .logo {
    display: flex;
    align-items: center;
}

.header .logo img {
    height: 48px;
    width: auto;
}

.header.scrolled .logo img {
    height: 40px;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 36px;
}

.nav-menu li a {
    font-size: 1.5rem;
    color: rgba(255, 255, 255, 0.9);
    letter-spacing: 1px;
    position: relative;
    padding: 4px 0;
    transition: var(--transition);
}

.header.scrolled .nav-menu li a {
    color: var(--color-text);
}

.nav-menu li a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--color-accent);
    transition: width 0.3s ease;
}

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

.nav-menu li a:hover::after,
.nav-menu li a.active::after {
    width: 100%;
}

.mobile-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
}

.mobile-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--color-white);
    transition: var(--transition);
}

.header.scrolled .mobile-toggle span {
    background: var(--color-primary);
}

/* === Footer === */
.footer {
    background: var(--color-dark);
    color: rgba(255, 255, 255, 0.7);
    padding: 60px 0 0;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1.5fr;
    gap: 40px;
    padding-bottom: 40px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-col h4 {
    color: var(--color-white);
    font-size: 1.6rem;
    font-weight: 600;
    margin-bottom: 24px;
    letter-spacing: 1px;
    position: relative;
    padding-bottom: 12px;
}

.footer-col h4::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 30px;
    height: 2px;
    background: var(--color-accent);
}

.footer-logo {
    margin-bottom: 20px;
}

.footer-logo img {
    height: 40px;
    width: auto;
    margin-bottom: 16px;
}

.footer-col p {
    font-size: 1.4rem;
    line-height: 1.8;
    color: rgba(255, 255, 255, 0.6);
}

.footer-col ul li {
    margin-bottom: 12px;
}

.footer-col ul li a {
    font-size: 1.4rem;
    color: rgba(255, 255, 255, 0.6);
    transition: var(--transition);
}

.footer-col ul li a:hover {
    color: var(--color-accent);
    padding-left: 4px;
}

.footer-contact li {
    font-size: 1.4rem;
    color: rgba(255, 255, 255, 0.6);
    margin-bottom: 16px;
    display: flex;
    align-items: flex-start;
    gap: 10px;
    line-height: 1.6;
}

.footer-contact li i {
    color: var(--color-accent);
    margin-top: 3px;
}

.footer-bottom {
    padding: 20px 0;
    text-align: center;
    font-size: 1.3rem;
    color: rgba(255, 255, 255, 0.4);
}

/* === Back to Top === */
.back-to-top {
    position: fixed;
    bottom: 40px;
    right: 40px;
    width: 44px;
    height: 44px;
    background: var(--color-accent);
    color: var(--color-white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: var(--transition);
    z-index: 999;
    font-size: 1.8rem;
    box-shadow: var(--shadow-md);
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    background: var(--color-accent-dark);
    transform: translateY(-3px);
}

/* === Page Banner (Inner Pages) === */
.page-banner {
    position: relative;
    height: 400px;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    display: flex;
    align-items: center;
    justify-content: center;
}

.page-banner::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
}

.page-banner .banner-content {
    position: relative;
    z-index: 1;
    text-align: center;
    color: var(--color-white);
}

.page-banner .banner-content h1 {
    font-size: 4.2rem;
    font-weight: 600;
    letter-spacing: 4px;
    margin-bottom: 12px;
}

.page-banner .banner-content .breadcrumb {
    font-size: 1.4rem;
    color: rgba(255, 255, 255, 0.7);
}

.page-banner .banner-content .breadcrumb a {
    color: var(--color-accent);
}

.page-banner .banner-content .breadcrumb span {
    margin: 0 8px;
}

/* === Responsive (Base) === */
@media (max-width: 1024px) {
    .container, .container-sm {
        padding: 0 24px;
    }
    .footer-grid {
        grid-template-columns: 1fr 1fr;
    }
}

@media (max-width: 768px) {
    html {
        font-size: 56.25%; /* 1rem = 9px */
    }
    .container, .container-sm {
        padding: 0 16px;
    }
    .section-title .cn-title {
        font-size: 2.8rem;
    }
}