:root[data-theme="dark"] {
    --bg-color: #0f172a;
    --card-bg: #1e293b;
    --text-color: #f8fafc;
    --accent-color: #38bdf8;
    --header-bg: rgba(15, 23, 42, 0.8);
}

:root[data-theme="light"] {
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-color: #0f172a;
    --accent-color: #0284c7;
    --header-bg: rgba(255, 255, 255, 0.8);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    transition: background 0.3s ease, color 0.3s ease;
}

body {
    font-family: 'Inter', system-ui, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* Header */
.main-header {
    background: var(--header-bg);
    backdrop-filter: blur(10px);
    padding: 1.5rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
}

.main-header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-weight: 800;
    letter-spacing: -1px;
}

.logo span { color: var(--accent-color); }

.nav-links {
    display: flex;
    list-style: none;
    align-items: center;
}

.nav-links li { margin: 0 1rem; }

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    opacity: 0.8;
}

.nav-links a:hover { opacity: 1; color: var(--accent-color); }

/* Theme Toggle */
.theme-btn {
    background: var(--card-bg);
    border: 1px solid var(--accent-color);
    padding: 8px;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1.2rem;
    margin-left: 1rem;
    display: flex;
    align-items: center;
}

/* Intro Section */
.intro-section {
    padding: 100px 0;
}

.intro-flex {
    display: flex;
    align-items: center;
    gap: 4rem;
}

.badge {
    color: var(--accent-color);
    font-weight: bold;
    text-transform: uppercase;
    font-size: 0.8rem;
    letter-spacing: 2px;
}

.intro-text h2 {
    font-size: 3.5rem;
    line-height: 1.1;
    margin: 1rem 0;
}

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

.cta-btn {
    padding: 12px 28px;
    border-radius: 8px;
    font-weight: bold;
    cursor: pointer;
    border: none;
    margin-right: 1rem;
}

.cta-btn.primary { background: var(--accent-color); color: white; }
.cta-btn.secondary { background: transparent; border: 2px solid var(--accent-color); color: var(--text-color); }

.intro-image img {
    width: 100%;
    border-radius: 20px;
    box-shadow: 0 20px 50px rgba(0,0,0,0.3);
}

/* Footer */
.main-footer {
    padding: 2rem 0;
    text-align: center;
    border-top: 1px solid rgba(128,128,128,0.2);
    margin-top: 50px;
}