/*
Theme Name: RSustain Elite
Theme URI: http://rsustain.co.uk
Description: A Tier-1 Corporate ESG Theme. High performance, low carbon.
Version: 3.0
Author: RSustain Team
*/

/* --- 1. Variables & Reset --- */
:root {
    --primary: #0A3622;      /* Deep British Green */
    --secondary: #165B3C;    /* Lighter Fern Green */
    --accent: #C5A059;       /* Executive Gold */
    --dark: #111111;
    --light: #F4F7F6;        /* Very light grey-green */
    --white: #FFFFFF;
    --font-heading: 'Helvetica Neue', Helvetica, Arial, sans-serif;
    --font-body: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}

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

body {
    background: var(--white);
    color: #444;
    font-family: var(--font-body);
    line-height: 1.6;
    font-size: 16px;
}

/* --- 2. Typography --- */
h1, h2, h3, h4 { color: var(--primary); font-family: var(--font-heading); font-weight: 700; line-height: 1.2; }
h1 { font-size: 3.5rem; letter-spacing: -1px; }
h2 { font-size: 2.2rem; margin-bottom: 1rem; position: relative; display: inline-block; }
h2::after { content: ''; display: block; width: 60px; height: 3px; background: var(--accent); margin-top: 10px; }
a { text-decoration: none; color: var(--secondary); transition: 0.3s; }
a:hover { color: var(--accent); }

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

/* --- 3. Header & Nav --- */
header {
    background: var(--white);
    padding: 20px 0;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    position: sticky;
    top: 0;
    z-index: 1000;
}
.navbar { display: flex; justify-content: space-between; align-items: center; }
.logo { font-size: 1.5rem; font-weight: 900; color: var(--primary); text-transform: uppercase; letter-spacing: -0.5px; }
.nav-menu ul { display: flex; list-style: none; gap: 30px; }
.nav-menu a { color: var(--primary); font-weight: 600; font-size: 0.95rem; text-transform: uppercase; }

/* --- 4. Hero Section --- */
.hero {
    background: linear-gradient(rgba(10, 54, 34, 0.9), rgba(10, 54, 34, 0.7)), url('https://source.unsplash.com/1600x900/?nature,forest') no-repeat center center/cover;
    height: 80vh;
    display: flex;
    align-items: center;
    color: var(--white);
    text-align: center;
}
.hero h1 { color: var(--white); margin-bottom: 20px; }
.hero p { font-size: 1.3rem; margin-bottom: 40px; opacity: 0.9; max-width: 700px; margin-left: auto; margin-right: auto; }

.btn {
    display: inline-block;
    padding: 15px 40px;
    background: var(--accent);
    color: var(--white);
    font-weight: bold;
    text-transform: uppercase;
    border-radius: 2px;
}
.btn:hover { background: #b08d4b; color: var(--white); }

/* --- 5. Features Grid --- */
.section { padding: 80px 0; }
.bg-light { background: var(--light); }

.grid-3 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 40px;
    margin-top: 50px;
}
.card {
    background: var(--white);
    padding: 40px;
    border-top: 4px solid var(--accent);
    box-shadow: 0 5px 20px rgba(0,0,0,0.03);
    transition: transform 0.3s ease;
}
.card:hover { transform: translateY(-10px); }
.icon { font-size: 2.5rem; margin-bottom: 20px; display: block; color: var(--primary); }

/* --- 6. Footer --- */
footer { background: #051b11; color: #888; padding: 60px 0 20px; font-size: 0.9rem; }
footer h4 { color: var(--white); margin-bottom: 20px; font-size: 1.2rem; }
footer ul { list-style: none; }
footer li { margin-bottom: 10px; }
footer a { color: #888; }
footer a:hover { color: var(--accent); }
.footer-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 40px; margin-bottom: 40px; }
.copyright { text-align: center; border-top: 1px solid #222; padding-top: 20px; }

/* --- 7. Responsive --- */
@media (max-width: 768px) {
    .hero h1 { font-size: 2.5rem; }
    .nav-menu { display: none; } /* Simplified for this demo */
}