/* Dark Theme */
body.dark-theme {
    --text-primary: #FFFFFF;
    --text-secondary: #B0B0B0;
    --background: #121212;
    --surface: #1E1E1E;
    --border-color: #333333;
    --shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
    --shadow-hover: 0 4px 8px rgba(0, 0, 0, 0.5);
}

body.dark-theme .header {
    background: var(--surface);
}

body.dark-theme .tool-card {
    background: var(--surface);
}

body.dark-theme .modal-content {
    background: var(--background);
}

body.dark-theme .form-input,
body.dark-theme .form-select,
body.dark-theme .form-textarea {
    background: var(--surface);
    color: var(--text-primary);
    border-color: var(--border-color);
}

body.dark-theme .calc-btn {
    background: var(--surface);
    color: var(--text-primary);
}

body.dark-theme .calc-btn:hover {
    background: var(--primary-color);
}

body.dark-theme .btn-secondary {
    background: var(--surface);
    color: var(--text-primary);
}

body.dark-theme .btn-secondary:hover {
    background: var(--border-color);
}

body.dark-theme .result-container {
    background: var(--surface);
}

body.dark-theme .footer {
    background: var(--surface);
}

/* Light Theme (Default) */
body.light-theme {
    --text-primary: #1E293B;
    --text-secondary: #64748B;
    --background: #F8FAFC;
    --surface: #FFFFFF;
    --border-color: #E2E8F0;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
    --shadow-hover: 0 10px 15px -3px rgba(0, 0, 0, 0.08);
}

/* Blue Theme */
body.blue-theme {
    --primary-color: #0D47A1;
    --secondary-color: #1565C0;
    --accent-color: #2196F3;
    --text-primary: #0D47A1;
    --text-secondary: #546E7A;
    --background: #E3F2FD;
    --surface: #BBDEFB;
    --border-color: #90CAF9;
}

body.blue-theme .tool-icon {
    background: var(--primary-color);
}

body.blue-theme .hero {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
}

/* Green Theme */
body.green-theme {
    --primary-color: #1B5E20;
    --secondary-color: #2E7D32;
    --accent-color: #4CAF50;
    --text-primary: #1B5E20;
    --text-secondary: #558B2F;
    --background: #E8F5E8;
    --surface: #C8E6C9;
    --border-color: #A5D6A7;
}

body.green-theme .tool-icon {
    background: var(--primary-color);
}

body.green-theme .hero {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
}

/* Purple Theme */
body.purple-theme {
    --primary-color: #4A148C;
    --secondary-color: #6A1B9A;
    --accent-color: #9C27B0;
    --text-primary: #4A148C;
    --text-secondary: #7B1FA2;
    --background: #F3E5F5;
    --surface: #E1BEE7;
    --border-color: #CE93D8;
}

body.purple-theme .tool-icon {
    background: var(--primary-color);
}

body.purple-theme .hero {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
}

/* Theme Toggle Animation */
.theme-toggle {
    position: relative;
    overflow: hidden;
}

.theme-toggle i {
    transition: var(--transition);
}

.theme-toggle:hover i {
    transform: rotate(180deg);
}

/* Theme Selection Modal */
.theme-selector {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    justify-content: center;
    margin-top: 2rem;
}

.theme-option {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    cursor: pointer;
    border: 3px solid transparent;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.theme-option:hover {
    transform: scale(1.1);
}

.theme-option.active {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(33, 150, 243, 0.3);
}

.theme-option.light {
    background: linear-gradient(135deg, #FFFFFF, #F5F5F5);
    border: 2px solid #E0E0E0;
}

.theme-option.dark {
    background: linear-gradient(135deg, #121212, #1E1E1E);
    border: 2px solid #333333;
}

.theme-option.blue {
    background: linear-gradient(135deg, #0D47A1, #1565C0);
}

.theme-option.green {
    background: linear-gradient(135deg, #1B5E20, #2E7D32);
}

.theme-option.purple {
    background: linear-gradient(135deg, #4A148C, #6A1B9A);
}

/* Auto Theme Detection */
@media (prefers-color-scheme: dark) {
    body.auto-theme {
        --text-primary: #FFFFFF;
        --text-secondary: #B0B0B0;
        --background: #121212;
        --surface: #1E1E1E;
        --border-color: #333333;
        --shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
        --shadow-hover: 0 4px 8px rgba(0, 0, 0, 0.5);
    }
}

/* Theme Transition */
body {
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Accessibility */
.theme-option:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* High Contrast Themes */
body.high-contrast-light {
    --text-primary: #000000;
    --text-secondary: #333333;
    --background: #FFFFFF;
    --surface: #F0F0F0;
    --border-color: #000000;
    --primary-color: #0066CC;
    --secondary-color: #004499;
}

body.high-contrast-dark {
    --text-primary: #FFFFFF;
    --text-secondary: #CCCCCC;
    --background: #000000;
    --surface: #111111;
    --border-color: #FFFFFF;
    --primary-color: #66B2FF;
    --secondary-color: #4488CC;
}

/* Color Blind Friendly Themes */
body.color-blind-friendly {
    --primary-color: #0072B2;
    --secondary-color: #D55E00;
    --success-color: #009E73;
    --warning-color: #E69F00;
    --error-color: #CC79A7;
}

/* Seasonal Themes */
body.christmas-theme {
    --primary-color: #C41E3A;
    --secondary-color: #228B22;
    --accent-color: #FFD700;
    --background: linear-gradient(135deg, #FFF5F5, #F5FFF5);
}

body.halloween-theme {
    --primary-color: #FF6600;
    --secondary-color: #2E2E2E;
    --accent-color: #9932CC;
    --background: linear-gradient(135deg, #FFF8F0, #F0F0F0);
}

/* Dynamic Theme Based on Time */
body.morning-theme {
    --primary-color: #FF6B35;
    --secondary-color: #F7931E;
    --background: linear-gradient(135deg, #FFF5E6, #FFE0B3);
}

body.afternoon-theme {
    --primary-color: #2196F3;
    --secondary-color: #1976D2;
    --background: linear-gradient(135deg, #E3F2FD, #BBDEFB);
}

body.evening-theme {
    --primary-color: #7C4DFF;
    --secondary-color: #651FFF;
    --background: linear-gradient(135deg, #F3E5F5, #E1BEE7);
}

body.night-theme {
    --primary-color: #311B92;
    --secondary-color: #4527A0;
    --background: linear-gradient(135deg, #1A1A2E, #16213E);
}

body.dark-theme .header {
    --glass-background: rgba(18, 18, 18, 0.6);
}

/* Cyber Theme */
body.cyber-theme {
    --primary-color: #00E5FF;
    --secondary-color: #7C4DFF;
    --accent-color: #FFEA00;
    --text-primary: #E0F7FA;
    --text-secondary: #80DEEA;
    --background: #0F172A;
    --surface: #1E293B;
    --border-color: #334155;
    --glass-background: rgba(15, 23, 42, 0.6);
}

/* Sunset Theme */
body.sunset-theme {
    --primary-color: #FB923C;
    --secondary-color: #F97316;
    --accent-color: #FBBF24;
    --text-primary: #3D2C29;
    --text-secondary: #6B4F4F;
    --background: #FFF5EB;
    --surface: #FFEAD5;
    --border-color: #FED7AA;
    --glass-background: rgba(255, 245, 235, 0.7);
}