:root {
    --deep-navy: #0A1A2F;
    --emerald: #00B894;
    --coral: #FF7675;
    --royal-purple: #6C5CE7;
    --clean-white: #FFFFFF;
    --light-gray: #F5F6FA;
    --dark-charcoal: #2D3436;
    --soft-text: #636e72;
    
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    --border-radius: 12px;
    --transition: all 0.3s ease;
}

/* Reset */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    line-height: 1.6;
    color: var(--dark-charcoal);
    background: var(--clean-white);
}

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

/* ==========================
   NAVIGATION
========================== */
.navbar {
    background: var(--clean-white);
    box-shadow: var(--shadow);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo a {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--deep-navy);
    text-decoration: none;
}

.nav-menu {
    display: flex;
    gap: 2rem;
}

.nav-link {
    color: var(--dark-charcoal);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
}

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

/* ==========================
   HERO SECTION
========================== */
.hero {
    padding: 120px 0 80px;
    background: linear-gradient(135deg, var(--light-gray) 0%, var(--clean-white) 100%);
}

.hero-content {
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.hero h1 {
    font-size: 3.5rem;
    font-weight: 700;
    color: var(--deep-navy);
    margin-bottom: 1.5rem;
    line-height: 1.1;
}

.hero-subtitle {
    font-size: 1.3rem;
    color: var(--soft-text);
    margin-bottom: 2.5rem;
    line-height: 1.6;
}

.hero-cta {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* ==========================
   BUTTONS
========================== */
.btn {
    display: inline-block;
    padding: 12px 32px;
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

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

.btn-primary:hover {
    background: #00a085;
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(0, 184, 148, 0.3);
}

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

.btn-secondary:hover {
    background: var(--deep-navy);
    color: var(--clean-white);
    transform: translateY(-2px);
}

/* ==========================
   PROBLEM / SOLUTION SECTION
========================== */
.problem-solution {
    padding: 80px 0;
    background: var(--clean-white);
}

.problem-solution h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    color: var(--deep-navy);
}

.ps-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    max-width: 1000px;
    margin: 0 auto;
}

.ps-column h3 {
    font-size: 1.5rem;
    margin-bottom: 2rem;
    color: var(--deep-navy);
    text-align: center;
}

.ps-item {
    background: var(--light-gray);
    padding: 2rem;
    border-radius: var(--border-radius);
    margin-bottom: 1.5rem;
    transition: var(--transition);
}

.ps-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow);
}

.ps-icon {
    font-size: 2rem;
    margin-bottom: 1rem;
}

.ps-item h4 {
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
    color: var(--dark-charcoal);
}

.ps-item p {
    color: var(--soft-text);
}

/* ==========================
   ENGINE TEASER SECTION
========================== */
.engine-teaser {
    padding: 80px 0;
    background: var(--light-gray);
}

.engine-teaser h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--deep-navy);
}

.teaser-subtitle {
    text-align: center;
    font-size: 1.2rem;
    color: var(--soft-text);
    margin-bottom: 3rem;
}

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

.preview-cta {
    margin-top: 2rem;
}

/* Mermaid Diagram Styling */
.mermaid {
    background: var(--clean-white);
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
}

/* ==========================
   FOOTER
========================== */
.footer {
    background: var(--deep-navy);
    color: var(--clean-white);
    padding: 3rem 0;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 2rem;
}

.footer-brand h3 {
    margin-bottom: 0.5rem;
}

.footer-links {
    display: flex;
    gap: 2rem;
}

.footer-links a {
    color: var(--clean-white);
    text-decoration: none;
    transition: var(--transition);
}

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

/* ==========================
   RESPONSIVE DESIGN
========================== */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2.5rem;
    }
    
    .ps-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .hero-cta {
        flex-direction: column;
        align-items: center;
    }
    
    .nav-menu {
        display: none; /* Placeholder for mobile nav later */
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
    
    .footer-links {
        justify-content: center;
    }
}