/* Theme Variables */
:root {
    /* Light Theme */
    --bg-primary: #FFFFFF;
    --bg-secondary: #F8F9FA;
    --bg-tertiary: #F1F3F5;
    --surface: #FFFFFF;
    --surface-hover: #F8F9FA;
    
    --text-primary: #1F2937;
    --text-secondary: #6B7280;
    --text-tertiary: #9CA3AF;
    
    --border-color: #E5E7EB;
    --border-hover: #D1D5DB;
    
    --primary: #2563EB;
    --primary-hover: #1D4ED8;
    --primary-light: #DBEAFE;
    
    --success: #10B981;
    --success-light: #D1FAE5;
    --warning: #F59E0B;
    --warning-light: #FEF3C7;
    --danger: #EF4444;
    --danger-light: #FEE2E2;
    
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] {
    /* Dark Theme */
    --bg-primary: #0F172A;
    --bg-secondary: #1E293B;
    --bg-tertiary: #334155;
    --surface: #1E293B;
    --surface-hover: #334155;
    
    --text-primary: #F1F5F9;
    --text-secondary: #CBD5E1;
    --text-tertiary: #94A3B8;
    
    --border-color: #334155;
    --border-hover: #475569;
    
    --primary: #3B82F6;
    --primary-hover: #2563EB;
    --primary-light: #1E3A8A;
    
    --success: #10B981;
    --success-light: #064E3B;
    --warning: #F59E0B;
    --warning-light: #78350F;
    --danger: #EF4444;
    --danger-light: #7F1D1D;
    
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.6);
}

/* Theme Toggle Button — standalone (only on pages without top-nav) */
.theme-toggle {
    position: fixed;
    top: 2rem;
    right: 2rem;
    z-index: 1000;
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--surface);
    border: 1px solid var(--border-color);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    box-shadow: var(--shadow-md);
}

/* Hide standalone toggle when top-nav is present */
.has-top-nav > .theme-toggle {
    display: none;
}

.theme-toggle:hover {
    transform: scale(1.05);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary);
}

.theme-toggle svg {
    color: var(--text-primary);
    transition: var(--transition);
}

.theme-toggle .sun-icon {
    display: block;
}

.theme-toggle .moon-icon {
    display: none;
}

[data-theme="dark"] .theme-toggle .sun-icon {
    display: none;
}

[data-theme="dark"] .theme-toggle .moon-icon {
    display: block;
}

/* Smooth theme transition */
body {
    transition: background-color 0.3s ease, color 0.3s ease;
}

* {
    transition: border-color 0.3s ease, background-color 0.3s ease;
}

@media (max-width: 768px) {
    .theme-toggle {
        top: 1rem;
        right: 1rem;
        width: 40px;
        height: 40px;
    }
}