/* ========================================
   MCHUAN 名传无线 - Global Styles
   Design System: IBM Carbon-Inspired Light Theme
   ======================================== */

/* CSS Variables */
:root {
    /* IBM-Inspired Colors - Light Theme */
    --bg-primary: #ffffff;
    --bg-secondary: #f4f4f4;
    --bg-tertiary: #e8e8e8;
    --bg-card: #ffffff;
    --bg-glass: rgba(255, 255, 255, 0.85);

    /* IBM Brand Colors */
    --brand-primary: #0f62fe;
    --brand-secondary: #0530ad;
    --brand-accent: #8a3ffc;
    --brand-gradient: linear-gradient(135deg, #0f62fe 0%, #8a3ffc 100%);

    /* Text Colors */
    --text-primary: #161616;
    --text-secondary: #525252;
    --text-muted: #8d8d8d;
    --text-on-brand: #ffffff;
    --text-gradient: linear-gradient(135deg, #161616 0%, #525252 100%);

    /* Border & Effects */
    --border-color: rgba(0, 0, 0, 0.1);
    --border-strong: rgba(0, 0, 0, 0.2);
    --shadow-subtle: 0 1px 3px rgba(0, 0, 0, 0.08);
    --shadow-card: 0 4px 16px rgba(0, 0, 0, 0.06);
    --shadow-card-hover: 0 8px 32px rgba(0, 0, 0, 0.12);
    --shadow-glow: 0 4px 20px rgba(15, 98, 254, 0.2);

    /* Spacing */
    --space-xs: 0.5rem;
    --space-sm: 1rem;
    --space-md: 1.5rem;
    --space-lg: 2rem;
    --space-xl: 3rem;
    --space-2xl: 4rem;
    --space-3xl: 6rem;

    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;

    /* Border Radius - IBM style (slightly larger, friendly) */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --radius-full: 9999px;
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-sans);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    letter-spacing: -0.02em;
    color: var(--text-primary);
}

h1 { font-size: clamp(2.5rem, 5vw, 4rem); }
h2 { font-size: clamp(2rem, 4vw, 3rem); }
h3 { font-size: clamp(1.5rem, 3vw, 2rem); }
h4 { font-size: clamp(1.25rem, 2vw, 1.5rem); }

p { margin-bottom: 1rem; color: var(--text-secondary); }
p:last-child { margin-bottom: 0; }

a {
    color: var(--brand-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--brand-secondary);
}

/* Container */
.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

/* ========================================
   Navigation
   ======================================== */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: var(--space-md) 0;
    background: #161616;
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    transition: all var(--transition-normal);
}

.nav.scrolled {
    padding: var(--space-sm) 0;
    background: rgba(22, 22, 22, 0.98);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
}

.nav-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-xl);
}

.nav-logo {
    display: flex;
    align-items: center;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.02em;
}

.nav-logo span {
    background: var(--brand-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-tagline {
    font-size: 0.75rem;
    font-weight: 400;
    color: var(--text-muted);
    letter-spacing: 0.05em;
    margin-left: var(--space-sm);
    padding-left: var(--space-sm);
    border-left: 1px solid var(--border-color);
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: var(--space-lg);
    list-style: none;
}

.nav-link {
    position: relative;
    color: rgba(255, 255, 255, 0.75);
    font-weight: 500;
    font-size: 0.875rem;
    padding: var(--space-xs) var(--space-sm);
    transition: all var(--transition-fast);
    border-radius: var(--radius-md);
}

.nav-link:hover {
    color: #ffffff;
    background: rgba(255, 255, 255, 0.15);
}

.nav-link.active {
    color: #ffffff;
    font-weight: 600;
    background: rgba(255, 255, 255, 0.2);
    box-shadow: 0 0 12px rgba(255, 255, 255, 0.15);
}

.nav-link-contact {
    color: var(--brand-primary);
    font-weight: 600;
}

.nav-logo {
    color: #ffffff;
}

.nav-phone {
    color: rgba(255, 255, 255, 0.6);
}

.lang-switch {
    background: rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.7);
    border-color: rgba(255, 255, 255, 0.15);
}

.lang-switch:hover {
    background: rgba(255, 255, 255, 0.15);
    color: #ffffff;
}

.lang-switch.active {
    background: var(--brand-primary);
    color: white;
    border-color: var(--brand-primary);
}

.nav-right {
    display: flex;
    align-items: center;
    gap: var(--space-lg);
}

.nav-phone {
    font-size: 0.8rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.nav-cta {
    display: flex;
    align-items: center;
    gap: var(--space-md);
}

.lang-switch {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    padding: var(--space-xs) var(--space-sm);
    background: var(--bg-secondary);
    border-radius: var(--radius-full);
    font-size: 0.875rem;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
    border: 1px solid transparent;
}

.lang-switch:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.lang-switch.active {
    background: var(--brand-primary);
    color: white;
    border-color: var(--brand-primary);
}

.nav-lang {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
}

/* ========================================
   Buttons
   ======================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-xs);
    padding: var(--space-sm) var(--space-lg);
    font-family: var(--font-sans);
    font-size: 0.9375rem;
    font-weight: 600;
    border-radius: var(--radius-md);
    border: none;
    cursor: pointer;
    transition: all var(--transition-normal);
    text-decoration: none;
}

.btn-primary {
    background: var(--brand-primary);
    color: white;
    box-shadow: 0 2px 8px rgba(15, 98, 254, 0.3);
}

.btn-primary:hover {
    background: var(--brand-secondary);
    transform: translateY(-1px);
    box-shadow: 0 4px 16px rgba(15, 98, 254, 0.4);
    color: white;
}

.btn-secondary {
    background: transparent;
    color: var(--brand-primary);
    border: 1px solid var(--brand-primary);
}

.btn-secondary:hover {
    background: rgba(15, 98, 254, 0.06);
    border-color: var(--brand-secondary);
    color: var(--brand-secondary);
}

/* ========================================
   Hero Section
   ======================================== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    padding-top: 80px;
    background: var(--bg-primary);
}

.hero-bg {
    position: absolute;
    inset: 0;
    background: radial-gradient(ellipse at 30% 20%, rgba(15, 98, 254, 0.08) 0%, transparent 50%),
                radial-gradient(ellipse at 70% 80%, rgba(138, 63, 252, 0.06) 0%, transparent 50%);
}

.hero-canvas {
    position: absolute;
    inset: 0;
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
    max-width: 900px;
    padding: var(--space-xl);
}

.hero-title {
    font-size: clamp(2.5rem, 6vw, 4.5rem);
    font-weight: 800;
    margin-bottom: var(--space-lg);
    background: linear-gradient(135deg, #161616 0%, #0f62fe 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1.1;
}

.hero-subtitle {
    font-size: clamp(1rem, 2vw, 1.25rem);
    color: var(--text-secondary);
    max-width: 700px;
    margin: 0 auto var(--space-xl);
    line-height: 1.8;
}

.hero-cta {
    display: flex;
    gap: var(--space-md);
    justify-content: center;
    flex-wrap: wrap;
}

/* Trust Stats */
.trust-stats {
    display: flex;
    justify-content: center;
    gap: var(--space-3xl);
    margin-top: var(--space-3xl);
    flex-wrap: wrap;
}

.stat-item {
    text-align: center;
}

.stat-number {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 800;
    background: var(--brand-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-family: var(--font-mono);
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-top: var(--space-xs);
}

/* ========================================
   Section Styles
   ======================================== */
.section {
    padding: var(--space-3xl) 0;
}

.section-alt {
    background: var(--bg-secondary);
}

.section-header {
    text-align: center;
    max-width: 800px;
    margin: 0 auto var(--space-2xl);
}

.section-title {
    font-size: clamp(2rem, 4vw, 3rem);
    margin-bottom: var(--space-md);
    color: var(--text-primary);
}

.section-subtitle {
    color: var(--text-secondary);
    font-size: 1.125rem;
}

/* ========================================
   Cards
   ======================================== */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--space-lg);
}

.card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--space-xl);
    transition: all var(--transition-normal);
    box-shadow: var(--shadow-card);
}

.card:hover {
    border-color: rgba(15, 98, 254, 0.3);
    transform: translateY(-4px);
    box-shadow: var(--shadow-card-hover);
}

.card-icon {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, rgba(15, 98, 254, 0.1) 0%, rgba(138, 63, 252, 0.1) 100%);
    border-radius: var(--radius-md);
    margin-bottom: var(--space-md);
    font-size: 1.5rem;
    color: var(--brand-primary);
}

.card-title {
    font-size: 1.25rem;
    margin-bottom: var(--space-sm);
    color: var(--text-primary);
}

.card-description {
    color: var(--text-secondary);
    margin-bottom: var(--space-md);
}

/* Feature Cards */
.feature-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    margin-bottom: var(--space-md);
    box-shadow: var(--shadow-card);
    transition: all var(--transition-normal);
}

.feature-card:hover {
    box-shadow: var(--shadow-card-hover);
    border-color: rgba(15, 98, 254, 0.2);
}

.feature-card h4 {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    margin-bottom: var(--space-sm);
    color: var(--text-primary);
}

.feature-card p {
    color: var(--text-secondary);
    margin: 0;
}

/* ========================================
   Bento Grid
   ======================================== */
.bento-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-lg);
}

.bento-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--space-xl);
    transition: all var(--transition-normal);
    box-shadow: var(--shadow-card);
}

.bento-card:hover {
    border-color: rgba(15, 98, 254, 0.3);
    box-shadow: var(--shadow-card-hover);
    transform: translateY(-2px);
}

.bento-card.large {
    grid-column: span 2;
}

.bento-card.highlight {
    background: linear-gradient(135deg, rgba(15, 98, 254, 0.04) 0%, rgba(138, 63, 252, 0.04) 100%);
    border-color: rgba(15, 98, 254, 0.2);
}

/* ========================================
   Products Grid
   ======================================== */
.products-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-lg);
}

.product-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--space-xl);
    display: flex;
    flex-direction: column;
    transition: all var(--transition-normal);
    box-shadow: var(--shadow-card);
}

.product-card:hover {
    border-color: rgba(15, 98, 254, 0.3);
    box-shadow: var(--shadow-card-hover);
    transform: translateY(-4px);
}

.product-card.highlight {
    background: linear-gradient(135deg, rgba(15, 98, 254, 0.04) 0%, rgba(138, 63, 252, 0.04) 100%);
    border-color: rgba(15, 98, 254, 0.25);
}

.product-header {
    display: flex;
    align-items: flex-start;
    gap: var(--space-md);
    margin-bottom: var(--space-lg);
}

.product-icon {
    font-size: 2.5rem;
    line-height: 1;
    flex-shrink: 0;
}

.product-title-group h3 {
    font-size: 1.5rem;
    font-weight: 700;
    margin: 0 0 0.25rem;
    color: var(--text-primary);
}

.product-tagline {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin: 0;
    line-height: 1.4;
}

.product-features {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
    margin-bottom: var(--space-lg);
}

.feature-item {
    display: flex;
    gap: var(--space-sm);
    padding: var(--space-md);
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.feature-emoji {
    font-size: 1.25rem;
    flex-shrink: 0;
    line-height: 1;
}

.feature-content {
    flex: 1;
    min-width: 0;
}

.feature-content h4 {
    font-size: 0.9375rem;
    font-weight: 600;
    margin: 0 0 0.375rem;
    color: var(--text-primary);
}

.feature-content p {
    font-size: 0.8125rem;
    color: var(--text-secondary);
    margin: 0;
    line-height: 1.5;
}

.btn-block {
    display: block;
    text-align: center;
    width: 100%;
    box-sizing: border-box;
    background: var(--brand-primary);
    color: white;
    font-weight: 600;
    padding: var(--space-sm) var(--space-lg);
    border-radius: var(--radius-md);
    transition: all var(--transition-normal);
    text-decoration: none;
}

.btn-block:hover {
    background: var(--brand-secondary);
    color: white;
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(15, 98, 254, 0.3);
}

/* ========================================
   Footer
   ======================================== */
.footer {
    background: #161616;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding: var(--space-2xl) 0 var(--space-lg);
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr repeat(3, 1fr);
    gap: var(--space-xl);
    margin-bottom: var(--space-xl);
}

.footer-brand {
    max-width: 300px;
}

.footer-logo {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: var(--space-md);
    color: #ffffff;
}

.footer-desc {
    color: rgba(255, 255, 255, 0.7);
    font-size: 0.875rem;
}

.footer-title {
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: rgba(255, 255, 255, 0.8);
    margin-bottom: var(--space-md);
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: var(--space-sm);
}

.footer-links a {
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.875rem;
    transition: color var(--transition-fast);
}

.footer-links a:hover {
    color: #ffffff;
}

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: var(--space-lg);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: #ffffff;
    font-size: 0.875rem;
}

/* Footer Inline */
.footer-inline {
    background: #161616;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding: var(--space-md) 0;
}

.footer-inline-row {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: var(--space-md);
    padding-bottom: var(--space-md);
}

.footer-inline-brand {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.footer-inline-logo {
    font-size: 1.25rem;
    font-weight: 700;
    color: #ffffff;
}

.footer-inline-tagline {
    font-size: 0.875rem;
    color: rgba(255, 255, 255, 0.7);
}

.footer-inline-nav {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    flex-wrap: wrap;
}

.footer-inline-nav a {
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.875rem;
    transition: color var(--transition-fast);
}

.footer-inline-nav a:hover {
    color: #ffffff;
}

.footer-inline-divider {
    color: rgba(255, 255, 255, 0.2);
}

.footer-inline-contact {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.875rem;
}

/* ========================================
   Utility Classes
   ======================================== */
.text-gradient {
    background: var(--brand-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.glass {
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--border-color);
}

/* ========================================
   Animations
   ======================================== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}

.animate-fade-in {
    animation: fadeInUp 0.6s ease forwards;
}

.animate-delay-1 { animation-delay: 0.1s; }
.animate-delay-2 { animation-delay: 0.2s; }
.animate-delay-3 { animation-delay: 0.3s; }
.animate-delay-4 { animation-delay: 0.4s; }

/* ========================================
   Responsive
   ======================================== */
@media (max-width: 1024px) {
    .products-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .product-card:first-child {
        grid-column: span 2;
    }

    .bento-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .bento-card.large {
        grid-column: span 2;
    }

    .footer-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }

    .nav-tagline {
        display: none;
    }

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

    .bento-card.large {
        grid-column: span 1;
    }

    .trust-stats {
        gap: var(--space-xl);
    }

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

    .footer-bottom {
        flex-direction: column;
        gap: var(--space-sm);
        text-align: center;
    }

    .footer-inline-row {
        flex-direction: column;
        text-align: center;
    }

    .footer-inline-nav {
        justify-content: center;
    }
}

@media (max-width: 640px) {
    .products-grid {
        grid-template-columns: 1fr;
    }

    .product-card:first-child {
        grid-column: span 1;
    }

    .product-card {
        padding: var(--space-lg);
    }

    .product-features {
        gap: var(--space-sm);
    }

    .feature-item {
        padding: var(--space-sm);
        gap: var(--space-xs);
    }

    .feature-emoji {
        font-size: 1rem;
    }

    .feature-content h4 {
        font-size: 0.875rem;
    }

    .feature-content p {
        font-size: 0.75rem;
        line-height: 1.4;
    }

    .product-header {
        margin-bottom: var(--space-md);
    }

    .product-icon {
        font-size: 2rem;
    }

    .product-title-group h3 {
        font-size: 1.25rem;
    }

    .container {
        padding: 0 var(--space-md);
    }
}

/* ========================================
   Scrollbar
   ======================================== */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--bg-tertiary);
    border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--brand-primary);
}