/* ====================================================================
   Modern Design Enhancements - China Sourcing
   Premium B2B eCommerce Interface
   Inspired by Alibaba, 1688, Stripe, Apple
   ==================================================================== */

/* ==================== Design System Variables ==================== */
:root {
    /* Primary Colors */
    --primary: #0D6EFD;
    --primary-dark: #0b5ed7;
    --primary-light: #3d8bfd;
    --secondary: #232526;

    /* Neutrals */
    --white: #FFFFFF;
    --gray-50: #F9FAFB;
    --gray-100: #F3F4F6;
    --gray-200: #E5E7EB;
    --gray-300: #D1D5DB;
    --gray-400: #9CA3AF;
    --gray-500: #6B7280;
    --gray-600: #4B5563;
    --gray-700: #374151;
    --gray-800: #1F2937;
    --gray-900: #111827;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);

    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius: 0.5rem;
    --radius-md: 0.75rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;

    /* Typography */
    --font-body: 'Poppins', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-heading: 'Rubik', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-smooth: 500ms cubic-bezier(0.4, 0, 0.2, 1);

    /* Spacing */
    --space-xs: 0.5rem;
    --space-sm: 0.75rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
}

/* ==================== Global Improvements ==================== */
* {
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-body);
    background-color: var(--gray-50);
    color: var(--gray-700);
    line-height: 1.6;
    letter-spacing: -0.01em;
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    letter-spacing: -0.02em;
    line-height: 1.2;
    font-weight: 700;
}

p {
    line-height: 1.7;
    color: var(--gray-600);
}

/* ==================== Modern Cards ==================== */
.service-item,
.blog-item,
.product-item {
    background: var(--white);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: all var(--transition-smooth);
    border: 1px solid var(--gray-200);
    box-shadow: var(--shadow-sm);
}

.service-item:hover,
.blog-item:hover,
.product-item:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
    border-color: var(--primary-light);
}

/* Image hover effects */
.service-item img,
.blog-item img,
.product-item img {
    transition: transform var(--transition-smooth);
}

.service-item:hover img,
.blog-item:hover img,
.product-item:hover img {
    transform: scale(1.08);
}

/* Card content spacing */
.service-item .p-4,
.blog-item .p-4,
.product-item .p-4 {
    padding: var(--space-xl);
}

/* ==================== Buttons Redesign ==================== */
.btn {
    font-weight: 600;
    border-radius: var(--radius-md);
    padding: 0.75rem 1.5rem;
    transition: all var(--transition-base);
    border: none;
    letter-spacing: -0.01em;
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.15);
    transform: translate(-50%, -50%);
    transition: width var(--transition-smooth), height var(--transition-smooth);
}

.btn:hover::before {
    width: 300px;
    height: 300px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    color: var(--white);
    box-shadow: 0 4px 12px rgba(13, 110, 253, 0.25);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(13, 110, 253, 0.35);
    background: linear-gradient(135deg, var(--primary-dark) 0%, var(--primary) 100%);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-light {
    background: var(--white);
    color: var(--primary);
    border: 2px solid var(--gray-200);
    box-shadow: var(--shadow);
}

.btn-light:hover {
    background: var(--gray-50);
    border-color: var(--primary);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-outline-light {
    border: 2px solid var(--white);
    background: transparent;
    backdrop-filter: blur(10px);
    color: var(--white);
}

.btn-outline-light:hover {
    background: var(--white);
    color: var(--primary);
    transform: translateY(-2px);
}

/* ==================== Navigation Improvements ==================== */
.navbar {
    backdrop-filter: blur(10px);
    background: rgba(255, 255, 255, 0.95);
    box-shadow: var(--shadow);
    transition: all var(--transition-base);
}

.sticky-top {
    transition: all var(--transition-base);
}

.navbar-brand {
    transition: transform var(--transition-base);
}

.navbar-brand:hover {
    transform: scale(1.02);
}

.navbar .nav-link {
    position: relative;
    font-weight: 500;
    letter-spacing: -0.01em;
    transition: color var(--transition-base);
}

.navbar .nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 50%;
    width: 0;
    height: 2px;
    background: var(--primary);
    transition: all var(--transition-base);
    transform: translateX(-50%);
    border-radius: 2px;
}

.navbar .nav-link:hover::after,
.navbar .nav-link.active::after {
    width: 100%;
}

.navbar .nav-link:hover {
    color: var(--primary);
}

/* Dropdown improvements */
.dropdown-menu {
    border: none;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-xl);
    padding: var(--space-sm);
    margin-top: 0.5rem;
    animation: slideDown var(--transition-base);
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.dropdown-item {
    border-radius: var(--radius-sm);
    padding: var(--space-sm) var(--space-md);
    transition: all var(--transition-fast);
    font-weight: 500;
}

.dropdown-item:hover {
    background: var(--primary);
    color: var(--white);
    transform: translateX(4px);
}

/* ==================== Hero Section Enhancements ==================== */
.hero-header {
    position: relative;
    overflow: hidden;
}

.hero-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(13, 110, 253, 0.8) 0%, rgba(11, 94, 215, 0.6) 100%);
    z-index: 1;
}

.hero-header .container {
    position: relative;
    z-index: 2;
}

.hero-header h1 {
    text-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    animation: fadeInUp 0.8s ease-out;
}

.hero-header p {
    animation: fadeInUp 1s ease-out;
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.hero-header .btn {
    animation: fadeInUp 1.2s ease-out;
}

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

/* ==================== Product Cards Premium Design ==================== */
.product-item {
    position: relative;
    background: var(--white);
    border-radius: var(--radius-xl);
    transition: all var(--transition-smooth);
}

.product-item::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    border-radius: var(--radius-xl);
    opacity: 0;
    transition: opacity var(--transition-smooth);
    box-shadow: 0 30px 60px -12px rgba(13, 110, 253, 0.25);
    z-index: -1;
}

.product-item:hover::after {
    opacity: 1;
}

.product-overlay {
    background: linear-gradient(135deg, rgba(13, 110, 253, 0.95) 0%, rgba(11, 94, 215, 0.9) 100%);
    backdrop-filter: blur(8px);
    transition: all var(--transition-smooth);
}

.product-overlay .btn {
    transform: translateY(20px);
    opacity: 0;
    transition: all var(--transition-smooth);
}

.product-item:hover .product-overlay .btn {
    transform: translateY(0);
    opacity: 1;
}

/* ==================== Section Headers ==================== */
.text-primary.text-uppercase {
    font-weight: 700;
    font-size: 0.875rem;
    letter-spacing: 0.1em;
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* ==================== Process Timeline Improvements ==================== */
.bg-primary.rounded-circle {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    box-shadow: 0 8px 20px rgba(13, 110, 253, 0.3);
    transition: all var(--transition-smooth);
}

.bg-success.rounded-circle {
    background: linear-gradient(135deg, #28a745 0%, #20c997 100%);
    box-shadow: 0 8px 20px rgba(40, 167, 69, 0.3);
}

.wow.fadeInUp {
    animation-duration: 0.8s;
}

/* ==================== Footer Enhancements ==================== */
.footer {
    background: linear-gradient(135deg, var(--gray-900) 0%, var(--secondary) 100%);
    position: relative;
}

.footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent 0%, var(--primary) 50%, transparent 100%);
}

.footer a {
    transition: all var(--transition-base);
}

.footer a:hover {
    color: var(--primary);
    transform: translateX(4px);
}

/* ==================== Input and Form Improvements ==================== */
.form-control,
.form-select {
    border-radius: var(--radius-md);
    border: 2px solid var(--gray-200);
    padding: 0.75rem 1rem;
    transition: all var(--transition-base);
    font-weight: 500;
}

.form-control:focus,
.form-select:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(13, 110, 253, 0.1);
    transform: translateY(-2px);
}

/* ==================== Loading Spinner ==================== */
#spinner .spinner-grow {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    box-shadow: 0 4px 12px rgba(13, 110, 253, 0.3);
}

/* ==================== Back to Top Button ==================== */
.back-to-top {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    transition: all var(--transition-base);
}

.back-to-top:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-2xl);
}

/* ==================== Testimonials ==================== */
.testimonial-item {
    transition: all var(--transition-smooth);
}

.testimonial-item:hover {
    transform: translateY(-4px);
}

.testimonial-item .testimonial-inner {
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    transition: all var(--transition-base);
}

.testimonial-item:hover .testimonial-inner {
    box-shadow: var(--shadow-lg);
}

/* ==================== Blog Grid ==================== */
.blog-item .overflow-hidden {
    border-radius: var(--radius-lg) var(--radius-lg) 0 0;
}

.blog-item h4 {
    transition: color var(--transition-base);
}

.blog-item:hover h4 {
    color: var(--primary);
}

/* ==================== Icons ==================== */
.fa, .fab, .fas, .far {
    transition: transform var(--transition-base);
}

.btn:hover .fa,
.btn:hover .fab,
.btn:hover .fas,
.btn:hover .far {
    transform: translateX(4px);
}

/* ==================== Smooth Scrolling ==================== */
html {
    scroll-behavior: smooth;
}

/* ==================== Micro-interactions ==================== */
@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.8;
    }
}

.btn-primary {
    animation: pulse 2s cubic-bezier(0.4, 0, 0.6, 1) infinite;
}

.btn-primary:hover {
    animation: none;
}

/* ==================== Responsive Refinements ==================== */
@media (max-width: 991px) {
    .service-item,
    .blog-item,
    .product-item {
        margin-bottom: var(--space-xl);
    }

    .hero-header h1 {
        font-size: 2rem;
    }

    .btn {
        padding: 0.625rem 1.25rem;
        font-size: 0.9rem;
    }
}

@media (max-width: 575px) {
    :root {
        --space-xl: 1.5rem;
        --space-2xl: 2rem;
    }

    .hero-header h1 {
        font-size: 1.75rem;
    }
}

/* ==================== Performance Optimizations ==================== */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* ==================== Print Styles ==================== */
@media print {
    .navbar,
    .footer,
    .back-to-top,
    #spinner {
        display: none !important;
    }
}