/* ============================================================
   科润化学 - 共享样式表
   字体: Inter + Noto Sans SC (SIL Open Font License)
   图标: Lucide Icons (MIT License)
   ============================================================ */

/* ── CSS 变量 ── */
:root {
    --color-primary: #FF6B35;
    --color-primary-dark: #E8551E;
    --color-primary-light: #FF8A5C;
    --color-primary-bg: rgba(255, 107, 53, 0.08);
    --color-primary-bg-hover: rgba(255, 107, 53, 0.14);
    --color-secondary: #1E293B;
    --color-gray-50: #F8FAFC;
    --color-gray-100: #F1F5F9;
    --color-gray-200: #E2E8F0;
    --color-gray-300: #CBD5E1;
    --color-gray-400: #94A3B8;
    --color-gray-500: #64748B;
    --color-gray-600: #475569;
    --color-gray-700: #334155;
    --color-gray-800: #1E293B;
    --color-gray-900: #0F172A;
    --font-heading: 'Inter', 'Noto Sans SC', system-ui, -apple-system, sans-serif;
    --font-body: 'Inter', 'Noto Sans SC', system-ui, -apple-system, sans-serif;
    --container-max-width: 1280px;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --transition-fast: 150ms ease;
    --transition-base: 200ms ease;
}

/* ── Reset & Base ── */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
    font-family: var(--font-body);
    font-weight: 400;
    color: var(--color-gray-800);
    background: #FFFFFF;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}
h1, h2, h3, h4, h5, h6 { font-family: var(--font-heading); font-weight: 600; line-height: 1.2; color: var(--color-gray-900); }
h1 { font-size: clamp(28px, 3.5vw, 36px); font-weight: 700; }
h2 { font-size: clamp(24px, 3vw, 32px); font-weight: 700; }
h3 { font-size: clamp(18px, 2vw, 22px); font-weight: 600; }
a { text-decoration: none; color: inherit; transition: color var(--transition-fast); }
ul { list-style: none; }
img { max-width: 100%; height: auto; display: block; }
:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 3px; border-radius: var(--radius-sm); }

/* ── Container ── */
.container { max-width: var(--container-max-width); margin: 0 auto; padding: 0 24px; }
@media (max-width: 640px) { .container { padding: 0 16px; } }

/* ── Buttons ── */
.btn {
    display: inline-flex; align-items: center; justify-content: center; gap: 8px;
    padding: 10px 24px; font-weight: 600; font-size: 15px; font-family: var(--font-body);
    border-radius: var(--radius-md); transition: all var(--transition-base); cursor: pointer;
    border: none; white-space: nowrap;
}
.btn i { width: 18px; height: 18px; }
.btn-primary { background: var(--color-primary); color: #fff; box-shadow: var(--shadow-sm); }
.btn-primary:hover { background: var(--color-primary-dark); box-shadow: var(--shadow-md); transform: translateY(-1px); }
.btn-outline { background: transparent; color: var(--color-gray-800); border: 1.5px solid var(--color-gray-300); }
.btn-outline:hover { border-color: var(--color-primary); color: var(--color-primary); background: var(--color-primary-bg); }
.btn-sm { padding: 8px 12px; font-size: 13px; }
.btn-white { background: #fff; color: var(--color-primary); font-weight: 600; }
.btn-white:hover { background: var(--color-gray-100); }
.btn-outline-white { background: transparent; border: 2px solid #fff; color: #fff; font-weight: 600; }
.btn-outline-white:hover { background: rgba(255,255,255,0.1); }

/* ============================================================
   HEADER & NAVIGATION
   ============================================================ */
.header {
    position: sticky; top: 0; z-index: 100;
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-gray-200);
}
.header-container {
    display: flex; align-items: center; justify-content: space-between;
    height: 76px; padding: 0 28px;
    max-width: var(--container-max-width); margin: 0 auto; gap: 20px;
}

/* Logo */
.logo { display: flex; align-items: center; gap: 12px; flex-shrink: 0; }
.logo-icon {
    width: 46px; height: 46px;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    border-radius: var(--radius-md);
    display: flex; align-items: center; justify-content: center;
    color: #fff; font-weight: 700; font-size: 22px;
    box-shadow: 0 2px 8px rgba(255, 107, 53, 0.3);
}
.logo-text { font-size: 22px; font-weight: 700; color: var(--color-gray-900); }
.logo-text span { color: var(--color-primary); font-weight: 600; }

/* ── Main Navigation ── */
.nav-menu { display: flex; align-items: center; gap: 0; }
.nav-item { position: relative; }
.nav-link {
    display: flex; align-items: center; gap: 4px;
    font-weight: 500; font-size: 15px; color: var(--color-gray-700);
    padding: 10px 16px; position: relative; white-space: nowrap;
    transition: color var(--transition-fast), background var(--transition-fast);
    cursor: pointer; border: none; background: none; font-family: var(--font-body);
}
.nav-link:hover { color: var(--color-primary); background: var(--color-primary-bg); }
.nav-link.active { color: var(--color-primary); font-weight: 600; }
.nav-link.active::after {
    content: ''; position: absolute; bottom: 0; left: 16px; right: 16px;
    height: 2.5px; background: var(--color-primary); border-radius: 2px;
}
.nav-link .arrow {
    width: 14px; height: 14px; transition: transform var(--transition-base);
    opacity: 0.5;
}
.nav-item:hover > .nav-link .arrow { transform: rotate(180deg); opacity: 1; }

/* ============================================================
   MEGA DROPDOWN MENU
   ============================================================ */
.dropdown-menu {
    position: absolute; top: 100%; left: 50%; transform: translateX(-50%) translateY(8px);
    background: #fff; border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    border: 1px solid var(--color-gray-200);
    opacity: 0; visibility: hidden;
    transition: opacity var(--transition-base), transform var(--transition-base), visibility var(--transition-base);
    z-index: 99; min-width: 680px; max-width: 900px;
    padding: 24px; pointer-events: none;
}
.nav-item:hover > .dropdown-menu,
.dropdown-menu:hover {
    opacity: 1; visibility: visible; pointer-events: auto;
    transform: translateX(-50%) translateY(0);
}

/* Mega dropdown grid layout */
.dropdown-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 20px; }
.dropdown-group { padding: 0; }
.dropdown-group-title {
    font-size: 14px; font-weight: 600; color: var(--color-gray-900);
    padding-bottom: 8px; margin-bottom: 10px;
    border-bottom: 2px solid var(--color-primary-bg);
    display: flex; align-items: center; gap: 6px;
}
.dropdown-group-title i { width: 16px; height: 16px; color: var(--color-primary); }
.dropdown-group ul { list-style: none; }
.dropdown-group li { margin-bottom: 2px; }
.dropdown-group a {
    display: flex; align-items: center; justify-content: space-between;
    padding: 7px 10px; font-size: 13px; color: var(--color-gray-600);
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}
.dropdown-group a::after {
    content: ''; display: inline-block; width: 0; height: 0;
    border-style: solid; border-width: 4px 0 4px 5px;
    border-color: transparent transparent transparent var(--color-gray-400);
    transition: all var(--transition-fast);
}
.dropdown-group a:hover {
    color: var(--color-primary); background: var(--color-primary-bg);
}
.dropdown-group a:hover::after {
    border-color: transparent transparent transparent var(--color-primary);
    transform: translateX(3px);
}

/* Single column dropdown (for items with fewer sub-items) */
.dropdown-menu.single-col { min-width: 220px; }
.dropdown-menu.single-col .dropdown-grid { grid-template-columns: 1fr; }

/* Wide dropdown for chemical additives */
.dropdown-menu.wide { min-width: 760px; max-width: 960px; }
.dropdown-menu.wide .dropdown-grid { grid-template-columns: repeat(3, 1fr); }

/* Dropdown arrow pointer */
.dropdown-menu::before {
    content: ''; position: absolute; top: -6px; left: 50%; transform: translateX(-50%) rotate(45deg);
    width: 12px; height: 12px; background: #fff;
    border-left: 1px solid var(--color-gray-200); border-top: 1px solid var(--color-gray-200);
}

/* ============================================================
   RIGHT-SIDE FIXED NAVIGATION
   ============================================================ */
.rightside-nav {
    position: fixed; right: 0; top: 50%; transform: translateY(-50%);
    z-index: 999; display: flex; flex-direction: column;
    background: #fff; border-radius: var(--radius-md) 0 0 var(--radius-md);
    box-shadow: -2px 4px 16px rgba(0, 0, 0, 0.12);
    border: 1px solid var(--color-gray-200); border-right: none;
    overflow: hidden;
}
.rightside-nav-item {
    position: relative; display: flex; align-items: center; justify-content: center;
    width: 52px; height: 52px; color: var(--color-gray-600);
    cursor: pointer; transition: all var(--transition-base);
    border: none; background: none; border-bottom: 1px solid var(--color-gray-100);
}
.rightside-nav-item:last-child { border-bottom: none; }
.rightside-nav-item:hover { background: var(--color-primary); color: #fff; }
.rightside-nav-item i { width: 22px; height: 22px; }

/* Tooltip label on hover */
.rightside-nav-item .rs-label {
    position: absolute; right: 60px; top: 50%; transform: translateY(-50%) translateX(8px);
    background: var(--color-gray-900); color: #fff; font-size: 13px; font-weight: 500;
    padding: 6px 12px; border-radius: var(--radius-sm); white-space: nowrap;
    opacity: 0; visibility: hidden;
    transition: all var(--transition-base); pointer-events: none;
}
.rightside-nav-item .rs-label::after {
    content: ''; position: absolute; right: -5px; top: 50%; transform: translateY(-50%);
    border-style: solid; border-width: 5px 0 5px 5px;
    border-color: transparent transparent transparent var(--color-gray-900);
}
.rightside-nav-item:hover .rs-label { opacity: 1; visibility: visible; transform: translateY(-50%) translateX(0); }

/* Expanded panel for items with more content */
.rightside-nav-item .rs-panel {
    position: absolute; right: 60px; top: 50%; transform: translateY(-50%) translateX(8px);
    background: #fff; border-radius: var(--radius-md);
    box-shadow: var(--shadow-xl); border: 1px solid var(--color-gray-200);
    padding: 20px; min-width: 240px; text-align: center;
    opacity: 0; visibility: hidden;
    transition: all var(--transition-base); pointer-events: none;
}
.rightside-nav-item:hover .rs-panel { opacity: 1; visibility: visible; transform: translateY(-50%) translateX(0); pointer-events: auto; }
.rs-panel-title { font-size: 14px; font-weight: 600; color: var(--color-gray-900); margin-bottom: 12px; }
.rs-panel-content { font-size: 13px; color: var(--color-gray-600); line-height: 1.6; }
.rs-panel-qr { width: 160px; height: 160px; margin: 8px auto; background: var(--color-gray-100); display: flex; align-items: center; justify-content: center; border-radius: var(--radius-sm); color: var(--color-gray-400); font-size: 12px; }
.rs-phone { font-size: 18px; font-weight: 700; color: var(--color-primary); }

/* Back to top button */
.rightside-nav-item.backtop { border-top: 2px solid var(--color-primary); }
.rightside-nav-item.backtop:hover { background: var(--color-primary-dark); }

/* Mobile: hide rightside nav on small screens */
@media (max-width: 1024px) { .rightside-nav { display: none; } }

/* ============================================================
   MOBILE MENU
   ============================================================ */
.mobile-menu-btn { display: none; background: none; border: none; cursor: pointer; padding: 10px; color: var(--color-gray-700); }
.mobile-menu-btn i { width: 24px; height: 24px; }
.mobile-nav-overlay {
    display: none; position: fixed; inset: 0; z-index: 199;
    background: rgba(15, 23, 42, 0.5); backdrop-filter: blur(2px);
    opacity: 0; pointer-events: none; transition: opacity var(--transition-base);
}
.mobile-nav-overlay.open { opacity: 1; pointer-events: auto; }
.mobile-nav-panel {
    display: none; position: fixed; top: 0; right: 0; bottom: 0; z-index: 200;
    width: 85%; max-width: 380px; background: #fff;
    box-shadow: -8px 0 32px rgba(0, 0, 0, 0.15);
    transform: translateX(100%);
    transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1);
    overflow-y: auto;
}
.mobile-nav-panel.open { transform: translateX(0); }
.mobile-nav-header {
    display: flex; align-items: center; justify-content: space-between;
    padding: 20px 24px; border-bottom: 1px solid var(--color-gray-200);
    position: sticky; top: 0; background: #fff; z-index: 1;
}
.mobile-nav-header h3 { font-size: 18px; }
.mobile-nav-close { background: none; border: none; cursor: pointer; color: var(--color-gray-700); padding: 8px; }
.mobile-nav-close i { width: 24px; height: 24px; }
.mobile-nav-list { padding: 12px 0; }
.mobile-nav-item { border-bottom: 1px solid var(--color-gray-100); }
.mobile-nav-link {
    display: flex; align-items: center; justify-content: space-between;
    padding: 14px 24px; font-size: 15px; font-weight: 500; color: var(--color-gray-800);
    width: 100%; background: none; border: none; cursor: pointer; font-family: var(--font-body);
}
.mobile-nav-link:hover { color: var(--color-primary); background: var(--color-gray-50); }
.mobile-nav-link i { width: 18px; height: 18px; transition: transform var(--transition-base); }
.mobile-nav-link.open i { transform: rotate(180deg); }
.mobile-subnav { display: none; padding: 0 24px 12px 36px; }
.mobile-subnav.open { display: block; }
.mobile-subnav a {
    display: block; padding: 10px 0; font-size: 14px; color: var(--color-gray-600);
    border-bottom: 1px dashed var(--color-gray-200);
}
.mobile-subnav a:last-child { border-bottom: none; }
.mobile-subnav a:hover { color: var(--color-primary); }
.mobile-nav-group-title { font-size: 12px; font-weight: 600; color: var(--color-gray-400); text-transform: uppercase; letter-spacing: 0.5px; padding: 8px 24px; margin-top: 4px; }

@media (max-width: 1024px) {
    .desktop-nav { display: none; }
    .mobile-menu-btn { display: flex; }
    .mobile-nav-overlay { display: block; }
    .mobile-nav-panel { display: block; }
}
@media (max-width: 480px) {
    .header-container { height: 64px; padding: 0 16px; }
    .logo-icon { width: 38px; height: 38px; font-size: 18px; }
    .logo-text { font-size: 18px; }
}

/* ============================================================
   BREADCRUMB
   ============================================================ */
.breadcrumb { padding: 16px 0; background: var(--color-gray-50); border-bottom: 1px solid var(--color-gray-200); }
.breadcrumb ol { display: flex; align-items: center; flex-wrap: wrap; gap: 8px; font-size: 14px; color: var(--color-gray-500); }
.breadcrumb li { display: flex; align-items: center; }
.breadcrumb li:not(:last-child)::after { content: '/'; margin-left: 8px; color: var(--color-gray-400); }
.breadcrumb a { color: var(--color-gray-600); }
.breadcrumb a:hover { color: var(--color-primary); }

/* ============================================================
   PAGE HEADER
   ============================================================ */
.page-header-section { padding: 32px 0 16px; }
.page-header-section h1 { margin-bottom: 8px; transition: all 0.3s ease; }
.page-header-section p { font-size: 15px; color: var(--color-gray-500); max-width: 700px; }

/* ============================================================
   FOOTER
   ============================================================ */
.footer { background: var(--color-gray-900); color: #fff; padding: 56px 0 28px; margin-top: 20px; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr 1.5fr; gap: 36px; margin-bottom: 44px; }
.footer-brand p { color: var(--color-gray-400); margin: 18px 0; font-size: 14px; line-height: 1.7; }
.footer-links h4 { color: #fff; font-size: 15px; margin-bottom: 18px; font-weight: 600; }
.footer-links ul li { margin-bottom: 10px; }
.footer-links ul li a { color: var(--color-gray-400); font-size: 13px; transition: color var(--transition-fast); }
.footer-links ul li a:hover { color: #fff; }
.footer-contact h4 { color: #fff; font-size: 15px; margin-bottom: 18px; font-weight: 600; }
.footer-contact p { display: flex; align-items: center; gap: 10px; color: var(--color-gray-400); font-size: 13px; margin-bottom: 10px; }
.footer-bottom { text-align: center; padding-top: 24px; border-top: 1px solid rgba(255, 255, 255, 0.08); color: var(--color-gray-500); font-size: 12px; }
.footer-logo-icon {
    width: 40px; height: 40px;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    border-radius: 10px; display: flex; align-items: center; justify-content: center;
    color: #fff; font-weight: 700;
}

@media (max-width: 1024px) {
    .footer-grid { grid-template-columns: repeat(2, 1fr); gap: 28px; }
}
@media (max-width: 640px) {
    .footer-grid { grid-template-columns: 1fr; gap: 24px; }
}

/* ============================================================
   UTILITY CLASSES
   ============================================================ */
.text-primary { color: var(--color-primary); }
.bg-primary-bg { background: var(--color-primary-bg); }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0; }