:root {
    --bg-primary: #f7f5f2;
    --bg-secondary: #efede9;
    --bg-dark: #1c1c1c;
    --bg-darker: #141414;
    --text-primary: #1a1a1a;
    --text-secondary: #5c5955;
    --text-light: #8a8782;
    --text-on-dark: #e8e5e0;
    --text-on-dark-muted: #a09b95;
    --accent-warm: #b8a69a;
    --accent-warm-light: #d4c8bd;
    --border-light: #e0dcd6;
    --border-medium: #c9c5bf;
    --border-dark: #3a3734;
    --white: #ffffff;
    --shadow-md: 0 4px 20px rgba(0,0,0,0.06);
    --shadow-lg: 0 12px 40px rgba(0,0,0,0.09);
    --transition-smooth: 0.5s cubic-bezier(0.25,0.1,0.25,1);
    --transition-fast: 0.3s cubic-bezier(0.25,0.1,0.25,1);
    --serif: 'STSong', 'Songti SC', 'SimSun', 'NSimSun', 'Noto Serif SC', serif;
    --serif-en: 'Georgia', 'Times New Roman', 'Cormorant Garamond', serif;
    --sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', 'Inter', sans-serif;
    --navbar-height: 80px;
}

* { margin:0; padding:0; box-sizing:border-box; }
html { scroll-behavior: smooth; -webkit-font-smoothing: antialiased; font-size: 16px; }
body {
    font-family: var(--sans);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    letter-spacing: 0.01em;
    overflow-x: hidden;
    min-height: 100vh;
}

::selection { background-color: var(--accent-warm); color: var(--white); }
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-primary); }
::-webkit-scrollbar-thumb { background: var(--border-medium); border-radius: 3px; }

:focus-visible { outline: 2px solid var(--accent-warm); outline-offset: 2px; }

/* NAVBAR */
.navbar {
    padding: 0 40px;
    height: var(--navbar-height);
    transition: background var(--transition-smooth), backdrop-filter var(--transition-smooth);
    z-index: 1030;
    background: transparent;
    mix-blend-mode: difference;
}
.navbar.scrolled {
    background: rgba(247,245,242,0.92) !important;
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    mix-blend-mode: normal;
    border-bottom: 0.5px solid var(--border-light);
}
.navbar .navbar-brand {
    font-family: var(--serif-en);
    font-size: 1.6rem;
    font-weight: 500;
    letter-spacing: 0.08em;
    color: #ffffff !important;
    transition: color var(--transition-fast);
    line-height: 1.1;
    text-decoration: none;
}
.navbar.scrolled .navbar-brand,
.navbar.scrolled .navbar-brand small { color: var(--text-primary) !important; }
.navbar-brand small {
    display: block;
    font-family: var(--serif);
    font-size: 0.55rem;
    font-weight: 400;
    letter-spacing: 0.22em;
    color: rgba(255,255,255,0.7) !important;
    text-transform: uppercase;
    transition: color var(--transition-fast);
}
.navbar.scrolled .navbar-brand small { color: var(--text-light) !important; }

.nav-link {
    font-family: var(--sans);
    font-size: 0.75rem;
    font-weight: 400;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: rgba(255,255,255,0.85) !important;
    padding: 0.5rem 0 !important;
    margin: 0 0.75rem;
    transition: color var(--transition-fast);
    position: relative;
    display: inline-block;
}
.nav-link::after { content: ''; position: absolute; bottom: -2px; left: 0; width: 0; height: 1px; background: currentColor; transition: width var(--transition-fast); }
.nav-link:hover::after,
.nav-link.active::after { width: 100%; }
.navbar.scrolled .nav-link { color: var(--text-primary) !important; }

.navbar .navbar-toggler { border: none; padding: 8px; box-shadow: none; outline: none; -webkit-tap-highlight-color: transparent; }
.navbar .navbar-toggler-icon {
    background-image: none; position: relative; width: 22px; height: 16px; display: flex; flex-direction: column; justify-content: center; gap: 5px;
}
.navbar .navbar-toggler-icon::before,
.navbar .navbar-toggler-icon::after { content: ''; display: block; width: 22px; height: 1.5px; background: #ffffff; border-radius: 1px; }
.navbar .navbar-toggler-icon-inner { display: block; width: 22px; height: 1.5px; background: #ffffff; border-radius: 1px; }
.navbar.scrolled .navbar-toggler-icon::before,
.navbar.scrolled .navbar-toggler-icon::after,
.navbar.scrolled .navbar-toggler-icon-inner { background: var(--text-primary); }

.btn-nav-cta {
    font-family: var(--sans); font-size: 0.7rem; font-weight: 500; letter-spacing: 0.12em; text-transform: uppercase;
    color: #ffffff !important; text-decoration: none; border: 1px solid rgba(255,255,255,0.45); padding: 9px 22px; border-radius: 0;
    transition: all var(--transition-fast); background: transparent; margin-left: 0.75rem; cursor: pointer; display: inline-block;
}
.btn-nav-cta:hover { background: #ffffff; color: var(--text-primary) !important; border-color: #ffffff; }
.navbar.scrolled .btn-nav-cta { color: var(--text-primary) !important; border-color: var(--border-medium); }
.navbar.scrolled .btn-nav-cta:hover { background: var(--text-primary); color: var(--bg-primary) !important; border-color: var(--text-primary); }

.offcanvas {
    background: rgba(18, 17, 16, 0.88);
    backdrop-filter: blur(40px) saturate(1.4);
    -webkit-backdrop-filter: blur(40px) saturate(1.4);
    border-left: none;
    width: 80vw !important;
    max-width: 80vw;
    box-shadow: 16px 0 60px rgba(0,0,0,0.6);
}
.offcanvas-header { padding: 0; border-bottom: none; min-height: 60px; }
.offcanvas-title { display: none; }

/* 极简关闭按钮 */
.btn-close-custom {
    position: absolute; top: 24px; right: 26px; width: 28px; height: 28px;
    background: transparent; border: none; cursor: pointer; z-index: 10;
    opacity: 0.4; transition: opacity 0.3s; -webkit-tap-highlight-color: transparent;
}
.btn-close-custom:hover { opacity: 0.8; }
.btn-close-custom::before,
.btn-close-custom::after {
    content: ''; position: absolute; top: 50%; left: 50%; width: 18px; height: 1px; background: #fff;
}
.btn-close-custom::before { transform: translate(-50%, -50%) rotate(45deg); }
.btn-close-custom::after { transform: translate(-50%, -50%) rotate(-45deg); }

.offcanvas-body {
    display: flex; flex-direction: column; justify-content: center;
    padding: 60px 40px 48px;
}

/* 公司名称区域 */
.menu-brand {
    margin-bottom: 52px;
    padding-bottom: 28px;
    border-bottom: 1px solid rgba(255,255,255,0.08);
    text-align: center;
}
.menu-brand .brand-en {
    font-family: var(--serif-en);
    font-size: 1.3rem;
    font-weight: 400;
    letter-spacing: 0.12em;
    color: rgba(255,255,255,0.65);
    display: block;
    margin-bottom: 6px;
}
.menu-brand .brand-cn {
    font-family: var(--serif);
    font-size: 0.55rem;
    font-weight: 400;
    letter-spacing: 0.28em;
    text-transform: uppercase;
    color: rgba(255,255,255,0.35);
}

/* 导航列表 */
.offcanvas .navbar-nav { width: 100%; }
.offcanvas .nav-item { margin-bottom: 2px; text-align: center; }

.offcanvas .nav-link {
    font-family: var(--serif) !important;
    font-size: 1.65rem !important;
    font-weight: 300 !important;
    letter-spacing: 0.1em !important;
    color: rgba(255,255,255,0.45) !important;
    padding: 15px 0 !important;
    margin: 0 !important;
    transition: all 0.4s cubic-bezier(0.25,0.1,0.25,1);
    text-decoration: none;
    display: inline-block;
    position: relative;
}
.offcanvas .nav-link::after {
    content: '';
    position: absolute;
    bottom: 10px;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 1px;
    background: var(--accent-warm-light);
    transition: width 0.4s ease;
}
.offcanvas .nav-link:hover {
    color: #fff !important;
    letter-spacing: 0.14em !important;
}
.offcanvas .nav-link:hover::after {
    width: 30px;
}
.offcanvas .nav-link.active {
    color: var(--accent-warm-light) !important;
    font-weight: 400 !important;
}

/* 遮罩 */
.offcanvas-backdrop { background: rgba(0,0,0,0.55) !important; }

@media (max-width: 991.98px) {
    .navbar { padding: 0 16px; mix-blend-mode: normal; background: rgba(20,20,20,0.85); }
    .navbar.scrolled { background: rgba(247,245,242,0.98) !important; }
    :root { --navbar-height: 64px; }
    .offcanvas { width: 80vw !important; max-width: 80vw; }
    .offcanvas-body { padding: 50px 30px 36px; }
    .menu-brand { margin-bottom: 40px; padding-bottom: 22px; }
    .menu-brand .brand-en { font-size: 1.1rem; }
    .offcanvas .nav-link { font-size: 1.4rem !important; padding: 13px 0 !important; }
    .btn-close-custom { top: 20px; right: 20px; }
}

/* HERO */
.hero {
    position: relative; width: 100%; height: 70vh; min-height: 500px; overflow: hidden; background: var(--bg-darker);
}
.hero-bg { position: absolute; inset: 0; z-index: 0; }
.hero-bg img { width: 100%; height: 100%; object-fit: cover; filter: brightness(0.45) saturate(0.6); transform: scale(1.02); animation: heroZoom 6s ease-out forwards; }
@keyframes heroZoom { from { transform: scale(1.06); } to { transform: scale(1.02); } }
.hero-overlay {
    position: absolute; inset: 0; z-index: 1;
    background: linear-gradient(180deg, rgba(20,20,20,0.45) 0%, rgba(20,20,20,0.2) 50%, rgba(20,20,20,0.5) 100%);
}
.hero-content { position: absolute; bottom: 15%; left: 8%; z-index: 2; max-width: 700px; animation: fadeUpHero 1s ease forwards; opacity: 0; animation-delay: 0.2s; }
@keyframes fadeUpHero { from { opacity: 0; transform: translateY(30px); } to { opacity: 1; transform: translateY(0); } }
.hero-tag { font-family: var(--sans); font-size: 0.65rem; letter-spacing: 0.2em; text-transform: uppercase; color: rgba(255,255,255,0.6); margin-bottom: 16px; display: block; }
.hero-title { font-family: var(--serif); font-size: clamp(2.2rem, 4vw, 3.5rem); font-weight: 300; letter-spacing: 0.04em; color: #fff; line-height: 1.3; text-shadow: 0 2px 12px rgba(0,0,0,0.5); }
.hero-title em { font-style: italic; font-weight: 400; color: var(--accent-warm-light); }
.hero-line { width: 50px; height: 1px; background: rgba(255,255,255,0.5); margin: 24px 0; }

/* 通用区块 */
.section { padding: 90px 0; }
@media (min-width: 1800px) { .section { padding: 130px 0; } }
.section-label { font-family: var(--sans); font-size: 0.65rem; letter-spacing: 0.2em; text-transform: uppercase; color: var(--text-light); margin-bottom: 16px; display: block; }
.section-title { font-family: var(--serif); font-size: clamp(2rem, 3.5vw, 2.8rem); font-weight: 300; letter-spacing: 0.04em; color: var(--text-primary); line-height: 1.3; margin-bottom: 24px; }
.section-body { font-family: var(--serif); font-size: 1rem; font-weight: 300; letter-spacing: 0.03em; color: var(--text-secondary); line-height: 1.9; }
.divider { width: 60px; height: 1px; background: var(--border-medium); margin: 32px 0; }

/* 选材哲学引用块 */
.philosophy-block {
    background: var(--bg-secondary);
    padding: 60px 48px;
    position: relative;
}
.philosophy-quote {
    font-family: var(--serif);
    font-size: 1.4rem;
    font-weight: 300;
    color: var(--text-primary);
    line-height: 1.8;
    max-width: 680px;
    margin: 0 auto;
    text-align: center;
}

/* 材料卡片 */
.material-card {
    background: var(--bg-primary);
    border: 1px solid var(--border-light);
    transition: all 0.3s;
    height: 100%;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    text-align: center;
}
.material-card:hover { border-color: var(--accent-warm); box-shadow: var(--shadow-md); }

/* 品牌名 - 顶部 */
.material-brand {
    font-family: var(--serif-en);
    font-size: .75rem;
    font-weight: 500;
    letter-spacing: 0.06em;
    color: var(--text-primary);
    padding: 20px 20px 12px;
}

/* 图片 - 中间 */
.material-img {
    width: 100%;
    aspect-ratio: 1 / 1;
    overflow: hidden;
    position: relative;
    background: var(--bg-secondary);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 18px;
}
.material-img img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
    transition: transform 0.5s ease;
    display: block;
}
.material-card:hover .material-img img { transform: scale(1.04); }

/* 材料名称与描述 - 底部 */
.material-body {
    padding: 16px 20px 20px;
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
}
.material-category {
    font-family: var(--sans);
    font-size: 0.6rem;
    letter-spacing: 0.12em;
    /*text-transform: uppercase;*/
    color: var(--text-light);
    margin-bottom: 10px;
}
.material-desc {
    font-size: 0.75rem;
    color: var(--text-secondary);
    font-weight: 300;
    line-height: 1.7;
}

/* 性能表格 */
.table-section { background: #262626; color: var(--text-on-dark); }
.table-section .section-label { color: var(--text-on-dark-muted); }
.table-section .section-title { color: var(--text-on-dark); }
.table-section .divider { background: var(--border-dark); }
.material-table {
    width: 100%;
    border-collapse: collapse;
}
.material-table th {
    font-family: var(--sans);
    font-size: 0.65rem;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--text-on-dark-muted);
    font-weight: 500;
    padding: 16px 12px;
    border-bottom: 1px solid var(--border-dark);
    text-align: left;
}
.material-table td {
    font-family: var(--serif);
    font-size: 0.9rem;
    font-weight: 300;
    color: var(--text-on-dark);
    padding: 16px 12px;
    border-bottom: 0.5px solid var(--border-dark);
    vertical-align: top;
}
.material-table tr:hover td { background: rgba(255,255,255,0.03); }

/* 联系模块 */
.contact-section { background: var(--bg-secondary); }
.contact-info-label {
    font-family: var(--sans);
    font-size: 0.6rem;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    color: var(--text-light);
}
.contact-info-value {
    font-family: var(--serif);
    font-size: 1rem;
    letter-spacing: 0.03em;
    color: var(--text-primary);
    text-decoration: none;
}
.contact-info-value:hover { color: var(--accent-warm); }
.qr-placeholder {
    width: 100%;
    max-width: 160px;
    aspect-ratio: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--white);
    border: 1px solid var(--border-light);
    margin: 0 auto;
}
.qr-placeholder img { width: 100%; height: auto; }

/* Footer */
.footer { background: var(--bg-darker); color: var(--text-on-dark-muted); font-size: 0.75rem; letter-spacing: 0.05em; }
.footer-brand { font-family: var(--serif-en); font-size: 1.3rem; color: var(--text-on-dark); }
.footer a { color: var(--text-on-dark-muted); text-decoration: none; transition: color 0.2s; font-size: 0.7rem; letter-spacing: 0.08em; }
.footer a:hover { color: var(--text-on-dark); }
.footer-bottom { border-top: 0.5px solid var(--border-dark); font-size: 0.65rem; }

.reveal { opacity: 0; transform: translateY(28px); transition: opacity 0.8s ease, transform 0.8s ease; will-change: transform, opacity; }
.reveal.visible { opacity: 1; transform: translateY(0); }
.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }

@media (max-width: 767.98px) {
    .section { padding: 50px 0; }
    .hero-title { font-size: 1.8rem; }
    .hero-content { left: 5%; right: 5%; }
}