:root[data-theme="light"] {
    /* Color Palette - Light Mode */
    --color-bg-primary: #F8FAFC;
    --color-bg-secondary: #FFFFFF;
    --color-bg-card: rgba(255, 255, 255, 0.8);
    --color-border: rgba(148, 163, 184, 0.2);
    --color-border-glow: rgba(99, 102, 241, 0.4);

    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #E0E7FF 0%, #DDD6FE 50%, #EDE9FE 100%);
    --gradient-accent: linear-gradient(90deg, #6366f1 0%, #8b5cf6 100%);
    --gradient-text: linear-gradient(135deg, #4F46E5 0%, #7C3AED 100%);

    /* Text Colors */
    --color-text-primary: #0F172A;
    --color-text-secondary: #475569;
    --color-text-muted: #64748B;
    --color-accent: #6366f1;
    --color-accent-bright: #4F46E5;

    /* Effects */
    --blur-glass: 12px;
    --shadow-glow: 0 0 40px rgba(99, 102, 241, 0.15);
    --shadow-card: 0 4px 20px rgba(0, 0, 0, 0.08);
}

/* Light Theme Specific Overrides */
:root[data-theme="light"] .hero-background {
    background: var(--gradient-primary);
    opacity: 0.6;
}

:root[data-theme="light"] .hero-background::before {
    background: radial-gradient(circle, rgba(99, 102, 241, 0.15) 0%, transparent 70%);
}

:root[data-theme="light"] .glass-card {
    background: var(--color-bg-card);
    box-shadow: var(--shadow-card);
    border: 1px solid var(--color-border);
}

:root[data-theme="light"] .glass-card:hover {
    border-color: var(--color-border-glow);
    box-shadow: 0 8px 32px rgba(99, 102, 241, 0.2);
}

:root[data-theme="light"] .emphasis-card {
    background: rgba(99, 102, 241, 0.08);
    border-color: var(--color-border-glow);
}

:root[data-theme="light"] .solution-detail.highlight {
    background: rgba(99, 102, 241, 0.08);
    border-left: 3px solid var(--color-accent);
}

:root[data-theme="light"] .method-step {
    background: rgba(99, 102, 241, 0.05);
}

:root[data-theme="light"] .main-nav {
    background: rgba(248, 250, 252, 0.95);
    border-bottom: 1px solid var(--color-border);
}

:root[data-theme="light"] .nav-link:hover {
    background: rgba(99, 102, 241, 0.1);
}

:root[data-theme="light"] .nav-link.active {
    background: rgba(99, 102, 241, 0.15);
}

:root[data-theme="light"] .footer {
    background: var(--color-bg-secondary);
    border-top: 1px solid var(--color-border);
}

:root[data-theme="light"] .cta-section {
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.08) 0%, rgba(139, 92, 246, 0.08) 100%);
}

:root[data-theme="light"] .hero-logo {
    filter: drop-shadow(0 0 30px rgba(99, 102, 241, 0.4));
}

:root[data-theme="light"] .solution-number {
    color: rgba(99, 102, 241, 0.12);
}

/* Theme Toggle Button */
.theme-toggle {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background: var(--gradient-accent);
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    box-shadow: 0 4px 20px rgba(139, 92, 246, 0.4);
    transition: var(--transition-smooth);
    z-index: 999;
}

.theme-toggle:hover {
    transform: scale(1.1) rotate(15deg);
    box-shadow: 0 8px 30px rgba(139, 92, 246, 0.6);
}

.theme-toggle:active {
    transform: scale(0.95);
}

/* Responsive adjustments for theme toggle */
@media (max-width: 768px) {
    .theme-toggle {
        width: 50px;
        height: 50px;
        bottom: 1.5rem;
        right: 1.5rem;
        font-size: 1.2rem;
    }
}