/* ========================================
   CSS Variables
   ======================================== */
:root {
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-secondary: #0f172a;
    --color-text: #334155;
    --color-text-light: #64748b;
    --color-background: #ffffff;
    --color-surface: #f8fafc;
    --color-border: #e2e8f0;
    --color-white: #ffffff;

    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;

    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 5rem;

    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 1rem;
    --radius-full: 9999px;

    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);

    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-background);
}

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

a {
    color: inherit;
    text-decoration: none;
}

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

/* ========================================
   Utilities
   ======================================== */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.highlight {
    color: var(--color-primary);
}

/* ========================================
   Buttons
   ======================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--radius-md);
    border: none;
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

.btn-primary:hover {
    background-color: var(--color-primary-dark);
    transform: translateY(-1px);
}

.btn-secondary {
    background-color: transparent;
    color: var(--color-secondary);
    border: 2px solid var(--color-border);
}

.btn-secondary:hover {
    border-color: var(--color-secondary);
    background-color: var(--color-surface);
}

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

.btn-white:hover {
    background-color: var(--color-surface);
    transform: translateY(-1px);
}

.btn-large {
    padding: 1rem 2rem;
    font-size: 1.125rem;
}

/* ========================================
   Language Switcher
   ======================================== */
.lang-switcher {
    display: flex;
    gap: 2px;
    background-color: var(--color-surface);
    border-radius: var(--radius-md);
    padding: 2px;
}

.lang-btn {
    padding: 0.375rem 0.625rem;
    font-size: 0.75rem;
    font-weight: 600;
    border: none;
    background: transparent;
    color: var(--color-text-light);
    cursor: pointer;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.lang-btn:hover {
    color: var(--color-text);
}

.lang-btn.active {
    background-color: var(--color-white);
    color: var(--color-primary);
    box-shadow: var(--shadow-sm);
}

/* ========================================
   Navigation
   ======================================== */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
}

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

.nav-logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--color-secondary);
}

.nav-logo-img {
    width: 36px;
    height: 36px;
    border-radius: var(--radius-sm);
}

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

.nav-links a:not(.btn) {
    color: var(--color-text);
    font-weight: 500;
    transition: color var(--transition-fast);
}

.nav-links a:not(.btn):hover {
    color: var(--color-primary);
}

/* ========================================
   Hero Section
   ======================================== */
.hero {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    align-items: center;
    min-height: 100vh;
    padding: calc(80px + var(--spacing-xl)) var(--spacing-md) var(--spacing-xl);
    max-width: 1200px;
    margin: 0 auto;
}

.hero-title {
    font-size: clamp(2.5rem, 5vw, 4rem);
    margin-bottom: var(--spacing-md);
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-lg);
    max-width: 500px;
}

.hero-actions {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

/* Hero Visual - Abstract Card */
.hero-visual {
    display: flex;
    justify-content: center;
    align-items: center;
}

.hero-card {
    width: 100%;
    max-width: 400px;
    background: linear-gradient(135deg, var(--color-surface) 0%, var(--color-white) 100%);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    overflow: hidden;
    animation: float 6s ease-in-out infinite;
}

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

.card-header {
    display: flex;
    gap: 6px;
    padding: var(--spacing-sm);
    background-color: var(--color-secondary);
}

.card-dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background-color: var(--color-text-light);
}

.card-dot:nth-child(1) { background-color: #ef4444; }
.card-dot:nth-child(2) { background-color: #eab308; }
.card-dot:nth-child(3) { background-color: #22c55e; }

.card-content {
    padding: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.card-bar {
    height: 12px;
    background: linear-gradient(90deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    border-radius: var(--radius-full);
    opacity: 0.8;
}

/* ========================================
   Section Styles
   ======================================== */
.section-title {
    font-size: clamp(2rem, 4vw, 2.5rem);
    text-align: center;
    margin-bottom: var(--spacing-sm);
}

.section-subtitle {
    text-align: center;
    color: var(--color-text-light);
    font-size: 1.125rem;
    margin-bottom: var(--spacing-2xl);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* ========================================
   Features Section
   ======================================== */
.features {
    padding: var(--spacing-2xl) var(--spacing-md);
    background-color: var(--color-surface);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
}

.feature-card {
    background-color: var(--color-white);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--color-primary);
    color: var(--color-white);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-md);
}

.feature-icon svg {
    width: 24px;
    height: 24px;
}

.feature-card h3 {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-xs);
}

.feature-card p {
    color: var(--color-text-light);
}

/* ========================================
   About Section
   ======================================== */
.about {
    padding: var(--spacing-2xl) var(--spacing-md);
}

.about-content {
    max-width: 700px;
    margin: 0 auto;
    text-align: center;
}

.about-content p {
    font-size: 1.125rem;
    color: var(--color-text-light);
    margin-top: var(--spacing-md);
}

/* ========================================
   CTA Section
   ======================================== */
.cta {
    padding: var(--spacing-2xl) var(--spacing-md);
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    text-align: center;
    color: var(--color-white);
}

.cta h2 {
    font-size: clamp(1.75rem, 4vw, 2.5rem);
    color: var(--color-white);
    margin-bottom: var(--spacing-sm);
}

.cta p {
    font-size: 1.125rem;
    opacity: 0.9;
    margin-bottom: var(--spacing-lg);
}

/* ========================================
   Footer
   ======================================== */
.footer {
    padding: var(--spacing-xl) var(--spacing-md);
    background-color: var(--color-secondary);
    color: var(--color-white);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-bottom: var(--spacing-lg);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

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

.footer-brand p {
    color: var(--color-text-light);
    margin-top: var(--spacing-xs);
}

.footer-links {
    display: flex;
    gap: var(--spacing-lg);
}

.footer-links a {
    color: var(--color-text-light);
    transition: color var(--transition-fast);
}

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

.footer-bottom {
    padding-top: var(--spacing-lg);
    text-align: center;
    color: var(--color-text-light);
    font-size: 0.875rem;
}

/* ========================================
   Responsive
   ======================================== */
@media (max-width: 768px) {
    .hero {
        grid-template-columns: 1fr;
        text-align: center;
        min-height: auto;
        padding-top: calc(80px + var(--spacing-xl));
    }

    .hero-subtitle {
        margin-left: auto;
        margin-right: auto;
    }

    .hero-actions {
        justify-content: center;
    }

    .hero-visual {
        order: -1;
    }

    .hero-card {
        max-width: 300px;
    }

    .nav-links a:not(.btn):not(.lang-btn) {
        display: none;
    }

    .lang-switcher {
        order: -1;
    }

    .footer-content {
        flex-direction: column;
        gap: var(--spacing-lg);
        text-align: center;
    }

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