/* ========================================
   Rongyu - Flat Design Website Styles
   ======================================== */

/* CSS Variables */
:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #3b82f6;
    --secondary: #0891b2;
    --accent: #f59e0b;
    --dark: #1e293b;
    --dark-light: #334155;
    --gray: #64748b;
    --gray-light: #94a3b8;
    --light: #f1f5f9;
    --lighter: #f8fafc;
    --white: #ffffff;
    --success: #10b981;
    --warning: #f59e0b;
    --error: #ef4444;
    --gradient-1: linear-gradient(135deg, #2563eb 0%, #0891b2 100%);
    --gradient-2: linear-gradient(135deg, #1e293b 0%, #334155 100%);
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1);
    --shadow-md: 0 10px 15px -3px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 20px 25px -5px rgb(0 0 0 / 0.1);
    --radius: 8px;
    --radius-lg: 16px;
    --transition: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, 'Noto Sans SC', sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--dark);
    background-color: var(--white);
    overflow-x: hidden;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition);
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    color: var(--dark);
}

h1 { font-size: clamp(2rem, 5vw, 3.5rem); }
h2 { font-size: clamp(1.75rem, 4vw, 2.5rem); }
h3 { font-size: clamp(1.25rem, 3vw, 1.5rem); }
h4 { font-size: 1.125rem; }

p {
    color: var(--gray);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 28px;
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--radius);
    border: 2px solid transparent;
    cursor: pointer;
    transition: var(--transition);
}

.btn-primary {
    background: var(--gradient-1);
    color: var(--white);
    border-color: var(--primary);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

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

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

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

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

.btn-large {
    padding: 16px 40px;
    font-size: 1.125rem;
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: var(--white);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.navbar.scrolled {
    box-shadow: var(--shadow);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 1.5rem;
}

.logo-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: var(--gradient-1);
    color: var(--white);
    border-radius: var(--radius);
    font-weight: 800;
}

.logo-text {
    color: var(--dark);
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 32px;
}

.nav-links a {
    font-weight: 500;
    color: var(--gray);
    position: relative;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary);
    transition: var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--primary);
}

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

.nav-actions {
    display: flex;
    align-items: center;
    gap: 16px;
}

.lang-switch {
    padding: 8px 16px;
    background: var(--light);
    border: none;
    border-radius: var(--radius);
    font-weight: 600;
    color: var(--dark);
    cursor: pointer;
    transition: var(--transition);
}

.lang-switch:hover {
    background: var(--primary);
    color: var(--white);
}

.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    padding: 8px;
    background: none;
    border: none;
    cursor: pointer;
}

.mobile-menu-btn span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--dark);
    transition: var(--transition);
}

/* Hero Section */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: var(--gradient-2);
    overflow: hidden;
    padding-top: 72px;
}

.hero-bg {
    position: absolute;
    inset: 0;
    overflow: hidden;
}

.hero-shape {
    position: absolute;
    border-radius: 50%;
    opacity: 0.1;
}

.shape-1 {
    width: 600px;
    height: 600px;
    background: var(--primary);
    top: -200px;
    right: -100px;
}

.shape-2 {
    width: 400px;
    height: 400px;
    background: var(--secondary);
    bottom: -100px;
    left: -100px;
}

.shape-3 {
    width: 300px;
    height: 300px;
    background: var(--accent);
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.hero h1 {
    color: var(--white);
    margin-bottom: 24px;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--gray-light);
    margin-bottom: 40px;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}

/* Section Styles */
section {
    padding: 100px 0;
}

.section-header {
    text-align: center;
    max-width: 600px;
    margin: 0 auto 60px;
}

.section-header h2 {
    margin-bottom: 16px;
}

.section-header p {
    font-size: 1.125rem;
}

/* Features Section */
.features {
    background: var(--lighter);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 30px;
}

.feature-card {
    background: var(--white);
    padding: 40px 30px;
    border-radius: var(--radius-lg);
    text-align: center;
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 24px;
    background: var(--gradient-1);
    border-radius: var(--radius-lg);
    position: relative;
}

.feature-icon::before {
    content: '';
    position: absolute;
    inset: 20px;
    background: var(--white);
    border-radius: var(--radius);
}

.icon-systems::after,
.icon-consulting::after,
.icon-design::after,
.icon-support::after {
    content: '';
    position: absolute;
    inset: 25px;
    background-size: contain;
    background-repeat: no-repeat;
    background-position: center;
}

.icon-systems::after {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='%232563eb'%3E%3Cpath d='M4 6h16v10H4V6zm0-2c-1.1 0-2 .9-2 2v10c0 1.1.9 2 2 2h6v2H8v2h8v-2h-2v-2h6c1.1 0 2-.9 2-2V6c0-1.1-.9-2-2-2H4z'/%3E%3C/svg%3E");
}

.icon-consulting::after {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='%232563eb'%3E%3Cpath d='M12 2C6.48 2 2 6.48 2 12s4.48 10 10 10 10-4.48 10-10S17.52 2 12 2zm-2 15l-5-5 1.41-1.41L10 14.17l7.59-7.59L19 8l-9 9z'/%3E%3C/svg%3E");
}

.icon-design::after {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='%232563eb'%3E%3Cpath d='M3 17.25V21h3.75L17.81 9.94l-3.75-3.75L3 17.25zM20.71 7.04c.39-.39.39-1.02 0-1.41l-2.34-2.34c-.39-.39-1.02-.39-1.41 0l-1.83 1.83 3.75 3.75 1.83-1.83z'/%3E%3C/svg%3E");
}

.icon-support::after {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='%232563eb'%3E%3Cpath d='M12 1c-4.97 0-9 4.03-9 9v7c0 1.66 1.34 3 3 3h3v-8H5v-2c0-3.87 3.13-7 7-7s7 3.13 7 7v2h-4v8h3c1.66 0 3-1.34 3-3v-7c0-4.97-4.03-9-9-9z'/%3E%3C/svg%3E");
}

.feature-card h3 {
    margin-bottom: 12px;
}

/* Services Preview */
.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 30px;
}

.service-card {
    background: var(--white);
    padding: 40px;
    border-radius: var(--radius-lg);
    border: 1px solid var(--light);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.service-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: var(--gradient-1);
    transform: scaleY(0);
    transition: var(--transition);
}

.service-card:hover {
    border-color: var(--primary-light);
    box-shadow: var(--shadow-md);
}

.service-card:hover::before {
    transform: scaleY(1);
}

.service-number {
    font-size: 3rem;
    font-weight: 800;
    color: var(--light);
    margin-bottom: 16px;
}

.service-card h3 {
    margin-bottom: 12px;
}

.service-link {
    display: inline-block;
    margin-top: 20px;
    color: var(--primary);
    font-weight: 600;
}

.service-link:hover {
    color: var(--primary-dark);
}

/* Stats Section */
.stats {
    background: var(--gradient-1);
    padding: 80px 0;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 40px;
    text-align: center;
}

.stat-number {
    font-size: 3.5rem;
    font-weight: 800;
    color: var(--white);
    margin-bottom: 8px;
}

.stat-number::after {
    content: '+';
}

.stat-label {
    font-size: 1rem;
    color: rgba(255, 255, 255, 0.8);
    text-transform: uppercase;
    letter-spacing: 1px;
}

/* CTA Section */
.cta {
    background: var(--lighter);
}

.cta-content {
    text-align: center;
    max-width: 600px;
    margin: 0 auto;
}

.cta-content h2 {
    margin-bottom: 16px;
}

.cta-content p {
    font-size: 1.125rem;
    margin-bottom: 32px;
}

/* Footer */
.footer {
    background: var(--dark);
    color: var(--gray-light);
    padding: 80px 0 30px;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 2fr;
    gap: 40px;
    margin-bottom: 60px;
}

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

.footer-brand .logo-text {
    color: var(--white);
}

.footer-brand p {
    color: var(--gray-light);
}

.footer-links h4,
.footer-contact h4 {
    color: var(--white);
    margin-bottom: 20px;
}

.footer-links ul {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.footer-links a:hover {
    color: var(--white);
}

.footer-contact p {
    margin-bottom: 8px;
    color: var(--gray-light);
}

.footer-contact a {
    color: var(--primary-light);
}

.footer-contact a:hover {
    color: var(--white);
}

.footer-bottom {
    padding-top: 30px;
    border-top: 1px solid var(--dark-light);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}

.footer-legal {
    display: flex;
    gap: 24px;
}

.footer-legal a:hover {
    color: var(--white);
}

.copyright {
    color: var(--gray);
    font-size: 0.875rem;
}

/* Mobile Navigation */
.mobile-nav {
    display: none;
    position: fixed;
    top: 72px;
    left: 0;
    right: 0;
    background: var(--white);
    padding: 20px;
    box-shadow: var(--shadow-md);
    z-index: 999;
}

.mobile-nav.active {
    display: block;
}

.mobile-nav ul {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.mobile-nav a {
    display: block;
    padding: 12px;
    font-weight: 500;
    color: var(--gray);
    border-radius: var(--radius);
}

.mobile-nav a:hover,
.mobile-nav a.active {
    background: var(--light);
    color: var(--primary);
}

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

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

    .mobile-menu-btn {
        display: flex;
    }

    .hero {
        min-height: auto;
        padding: 120px 0 80px;
    }

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

    section {
        padding: 60px 0;
    }

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

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

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

@media (max-width: 480px) {
    .hero-buttons {
        flex-direction: column;
    }

    .btn {
        width: 100%;
    }

    .stat-number {
        font-size: 2.5rem;
    }
}