/* =========================================
   1. VARIABLES & RESET
   ========================================= */
:root {
    /* Colors */
    --color-primary: #16a34a;
    /* Green Energy - Primary Action */
    --color-primary-dark: #15803d;

    --color-structure: #0f172a;
    /* Deep Navy Blue - Headings & Structure */
    --color-structure-light: #1e293b;

    --color-accent: #eab308;
    /* Yellow - Highlights & CTAs */
    --color-accent-hover: #ca8a04;

    --color-bg-light: #f1f5f9;
    /* Crisp Light Gray */
    --color-bg-white: #ffffff;

    --color-text-main: #334155;
    --color-text-light: #64748b;
    --color-border: #cbd5e1;

    /* Typography */
    --font-main: 'Inter', system-ui, -apple-system, sans-serif;

    /* Spacing */
    --container-width: 1200px;
    --spacing-xs: 0.5rem;
    /* 8px */
    --spacing-sm: 1rem;
    /* 16px */
    --spacing-md: 2rem;
    /* 32px */
    --spacing-lg: 4rem;
    /* 64px */
    --spacing-xl: 6rem;
    /* 96px */

    /* Transitions */
    --transition-fast: 0.2s ease;

    /* Shadows */
    --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);
}

*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-main);
    color: var(--color-text-main);
    background-color: var(--color-bg-white);
    line-height: 1.6;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
    border-radius: 4px;
}

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

ul {
    list-style: none;
}

/* =========================================
   2. TYPOGRAPHY
   ========================================= */
h1,
h2,
h3,
h4,
h5,
h6 {
    color: var(--color-structure);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--spacing-sm);
}

h1 {
    font-size: 3rem;
    letter-spacing: -0.02em;
}

h2 {
    font-size: 2.25rem;
    letter-spacing: -0.01em;
}

h3 {
    font-size: 1.5rem;
}

h4 {
    font-size: 1.125rem;
}

p {
    margin-bottom: var(--spacing-sm);
    color: var(--color-text-main);
}

.text-lead {
    font-size: 1.25rem;
    color: var(--color-text-light);
    max-width: 700px;
    line-height: 1.6;
}

.text-small {
    font-size: 0.875rem;
    color: var(--color-text-light);
}

.text-white {
    color: white !important;
}

.text-accent {
    color: var(--color-accent);
}

/* =========================================
   3. LAYOUT UTILITIES
   ========================================= */
.container {
    width: 90%;
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 var(--spacing-sm);
}

.section {
    padding: var(--spacing-lg) 0;
}

.grid {
    display: grid;
    gap: var(--spacing-md);
}

.grid-2 {
    grid-template-columns: 1fr 1fr;
}

.grid-3 {
    grid-template-columns: repeat(3, 1fr);
}

.grid-4 {
    grid-template-columns: repeat(4, 1fr);
}

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

.flex-between {
    justify-content: space-between;
}

.flex-center {
    justify-content: center;
}

.flex-column {
    flex-direction: column;
}

/* Sticky Footer Layout Fix */
body {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

@media (max-width: 768px) {

    .grid-2,
    .grid-3,
    .grid-4 {
        grid-template-columns: 1fr;
    }

    h1 {
        font-size: 2.25rem;
    }

    h2 {
        font-size: 1.75rem;
    }

    .flex {
        flex-wrap: wrap;
    }
}

/* =========================================
   4. COMPONENTS
   ========================================= */
/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    border-radius: 4px;
    font-weight: 600;
    text-align: center;
    cursor: pointer;
    border: 2px solid transparent;
    font-size: 1rem;
    transition: all 0.2s ease;
}

/* Primary is now YELLOW/ACCENT for high visibility CTAs */
.btn-primary {
    background-color: var(--color-accent);
    color: var(--color-structure);
    /* Dark text on yellow for contrast */
}

.btn-primary:hover {
    background-color: var(--color-accent-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

/* Secondary is now GREEN/STRUCTURE usually Outline */
.btn-outline {
    background-color: transparent;
    border-color: var(--color-primary);
    color: var(--color-primary);
}

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

.btn-white-outline {
    border-color: white;
    color: white;
}

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

/* Cards */
.card {
    background: white;
    border: 1px solid var(--color-border);
    padding: var(--spacing-md);
    border-radius: 6px;
    transition: var(--transition-fast);
    box-shadow: var(--shadow-sm);
    display: flex;
    flex-direction: column;
    height: 100%;
}

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

.card h3 {
    color: var(--color-structure);
    margin-bottom: var(--spacing-xs);
}

/* Hero Overlay Utility */
.hero-wrapper {
    position: relative;
    background-size: cover;
    background-position: center;
    color: white;
    overflow: hidden;
}

.hero-overlay {
    position: absolute;
    inset: 0;
    background: linear-gradient(to right, rgba(15, 23, 42, 0.9), rgba(15, 23, 42, 0.6));
    z-index: 1;
}

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

/* =========================================
   5. HEADER & NAV
   ========================================= */
.header {
    background-color: white;
    border-bottom: 3px solid var(--color-primary);
    /* Green line at top */
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-sm);
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--color-structure);
    letter-spacing: -0.03em;
    text-transform: uppercase;
}

.logo span {
    color: var(--color-primary);
    /* BI in green? or Power in green? Let's do Power in Green */
}

.nav-links {
    display: flex;
    gap: var(--spacing-md);
}

.nav-links a {
    font-weight: 600;
    color: var(--color-structure);
    font-size: 0.95rem;
    text-transform: uppercase;
    font-size: 0.85rem;
    letter-spacing: 0.05em;
}

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

.mobile-menu-btn {
    display: none;
    font-size: 1.5rem;
    background: none;
    border: none;
    cursor: pointer;
    color: var(--color-structure);
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: white;
        flex-direction: column;
        padding: var(--spacing-md);
        border-bottom: 2px solid var(--color-primary);
        gap: var(--spacing-sm);
    }

    .nav-links.active {
        display: flex;
    }

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

/* =========================================
   6. FOOTER
   ========================================= */
.footer {
    background-color: var(--color-structure);
    color: white;
    padding: var(--spacing-lg) 0;
    margin-top: auto;
    border-top: 4px solid var(--color-primary);
}

.footer h4 {
    color: white;
    margin-bottom: var(--spacing-sm);
    font-size: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    opacity: 0.9;
}

.footer p,
.footer a {
    color: #cbd5e1;
    font-size: 0.9rem;
}

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

.footer-bottom {
    border-top: 1px solid var(--color-structure-light);
    margin-top: var(--spacing-md);
    padding-top: var(--spacing-md);
    text-align: center;
    font-size: 0.8rem;
    color: #64748b;
}

/* Utility for Image Columns */
.img-cover {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 6px;
    box-shadow: var(--shadow-md);
}