/**
 * Resistor Calculator Pro - Modern Styles
 * 
 * A beautiful, responsive design with dark mode support
 */

/* ============================================
   CSS Custom Properties (Design System)
   ============================================ */
:root {
    /* Colors - Light Mode */
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --primary-light: #818cf8;
    --secondary-color: #ec4899;
    --accent-color: #14b8a6;
    
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --bg-card: #ffffff;
    
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-tertiary: #94a3b8;
    
    --border-color: #e2e8f0;
    --border-hover: #cbd5e1;
    
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    
    --resistor-body: #e8d4b8;
    --resistor-lead: #c0c0c0;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* Dark Mode */
[data-theme="dark"],
.resistor-calculator-wrapper[data-theme="dark"],
@media (prefers-color-scheme: dark) {
    .resistor-calculator-wrapper[data-theme="auto"] {
        --primary-color: #818cf8;
        --primary-hover: #a5b4fc;
        --primary-light: #c7d2fe;
        --secondary-color: #f472b6;
        --accent-color: #2dd4bf;
        
        --bg-primary: #0f172a;
        --bg-secondary: #1e293b;
        --bg-tertiary: #334155;
        --bg-card: #1e293b;
        
        --text-primary: #f1f5f9;
        --text-secondary: #cbd5e1;
        --text-tertiary: #64748b;
        
        --border-color: #334155;
        --border-hover: #475569;
        
        --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
        --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
        --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -2px rgba(0, 0, 0, 0.3);
        --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.5), 0 10px 10px -5px rgba(0, 0, 0, 0.3);
        
        --resistor-body: #8b7355;
        --resistor-lead: #9ca3af;
    }
}

/* ============================================
   Base Styles
   ============================================ */
.resistor-calculator-wrapper {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--bg-secondary);
    padding: var(--spacing-xl) var(--spacing-md);
    border-radius: var(--radius-xl);
    margin: var(--spacing-xl) 0;
    transition: background-color var(--transition-base), color var(--transition-base);
}

.resistor-calculator-container {
    max-width: 900px;
    margin: 0 auto;
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    overflow: hidden;
    transition: background-color var(--transition-base), box-shadow var(--transition-base);
}

/* ============================================
   Header
   ============================================ */
.calculator-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-xl);
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-hover) 100%);
    color: white;
    position: relative;
    overflow: hidden;
}

.calculator-header::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, transparent 70%);
    animation: pulse 4s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { transform: scale(1); opacity: 0.5; }
    50% { transform: scale(1.1); opacity: 0.8; }
}

.calculator-title {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin: 0;
    font-size: 1.75rem;
    font-weight: 700;
    position: relative;
    z-index: 1;
}

.calculator-icon {
    width: 32px;
    height: 32px;
    stroke-width: 2;
}

.theme-toggle {
    background: rgba(255, 255, 255, 0.2);
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: var(--radius-md);
    padding: var(--spacing-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
    position: relative;
    z-index: 1;
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: scale(1.05);
}

.theme-toggle svg {
    width: 20px;
    height: 20px;
    stroke: white;
    stroke-width: 2;
    transition: all var(--transition-base);
}

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

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

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

/* ============================================
   Mode Selector
   ============================================ */
.mode-selector {
    display: flex;
    gap: var(--spacing-sm);
    padding: var(--spacing-lg);
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    overflow-x: auto;
    scrollbar-width: thin;
    scrollbar-color: var(--border-hover) transparent;
}

.mode-selector::-webkit-scrollbar {
    height: 6px;
}

.mode-selector::-webkit-scrollbar-track {
    background: transparent;
}

.mode-selector::-webkit-scrollbar-thumb {
    background: var(--border-hover);
    border-radius: 3px;
}

.mode-btn {
    flex: 1;
    min-width: 100px;
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-card);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.875rem;
    cursor: pointer;
    transition: all var(--transition-fast);
    white-space: nowrap;
}

.mode-btn:hover {
    border-color: var(--primary-light);
    color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.mode-btn.active {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-hover) 100%);
    border-color: var(--primary-color);
    color: white;
    box-shadow: var(--shadow-lg);
}

/* ============================================
   Calculator Content
   ============================================ */
.calculator-content {
    padding: var(--spacing-xl);
    min-height: 500px;
}

.calculator-mode {
    animation: fadeIn var(--transition-base);
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.mode-description {
    text-align: center;
    color: var(--text-secondary);
    margin: 0 0 var(--spacing-lg);
    font-size: 0.95rem;
}

/* ============================================
   Resistor Visual
   ============================================ */
.resistor-visual {
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-tertiary) 100%);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.06);
}

.resistor-svg {
    width: 100%;
    height: auto;
    filter: drop-shadow(0 4px 6px rgba(0, 0, 0, 0.1));
    transition: transform var(--transition-slow);
}

.resistor-svg:hover {
    transform: scale(1.02);
}

.resistor-svg .band {
    transition: fill var(--transition-base);
}

/* ============================================
   Color Selectors
   ============================================ */
.color-selectors {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
}

.color-selector-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.color-selector-group label {
    font-weight: 600;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.color-select {
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-card);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%23475569' d='M6 9L1 4h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 0.75rem center;
    padding-right: 2.5rem;
}

.color-select:hover {
    border-color: var(--primary-light);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.color-select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

/* ============================================
   Result Display
   ============================================ */
.result-display {
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-tertiary) 100%);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    border: 2px solid var(--border-color);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.result-value,
.result-tolerance,
.result-tempcoef,
.result-range,
.result-code-type,
.result-power,
.result-wattage {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm) 0;
}

.result-label {
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.result-number {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--primary-color);
    text-align: right;
}

.tolerance-value,
.tempcoef-value,
.range-value,
.code-type-value,
.power-value,
.wattage-value {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 1.1rem;
}

/* ============================================
   SMD Calculator
   ============================================ */
.smd-input-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
}

.smd-input-group label {
    font-weight: 600;
    color: var(--text-secondary);
}

.smd-input {
    padding: var(--spacing-md);
    background: var(--bg-card);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 1.25rem;
    font-weight: 600;
    text-align: center;
    text-transform: uppercase;
    transition: all var(--transition-fast);
}

.smd-input:hover {
    border-color: var(--primary-light);
}

.smd-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.smd-examples {
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.smd-examples h4 {
    margin: 0 0 var(--spacing-md);
    color: var(--text-primary);
    font-size: 1rem;
}

.smd-examples ul {
    list-style: none;
    padding: 0;
    margin: 0;
    display: grid;
    gap: var(--spacing-sm);
}

.smd-examples li {
    padding: var(--spacing-sm);
    background: var(--bg-card);
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.smd-examples code {
    background: var(--primary-color);
    color: white;
    padding: 2px 8px;
    border-radius: 4px;
    font-weight: 600;
    margin-right: var(--spacing-sm);
}

/* ============================================
   Utilities Calculator
   ============================================ */
.utility-tabs {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xl);
    border-bottom: 2px solid var(--border-color);
}

.utility-tab {
    flex: 1;
    padding: var(--spacing-md);
    background: transparent;
    border: none;
    border-bottom: 3px solid transparent;
    color: var(--text-secondary);
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.utility-tab:hover {
    color: var(--primary-color);
    background: var(--bg-secondary);
}

.utility-tab.active {
    color: var(--primary-color);
    border-bottom-color: var(--primary-color);
}

.utility-content {
    display: none;
}

.utility-content.active {
    display: block;
    animation: fadeIn var(--transition-base);
}

.input-group {
    margin-bottom: var(--spacing-lg);
}

.input-group label {
    display: block;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
    font-size: 0.95rem;
}

.input-group input[type="number"] {
    width: 100%;
    padding: var(--spacing-md);
    background: var(--bg-card);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 1rem;
    transition: all var(--transition-fast);
}

.input-group input[type="number"]:hover {
    border-color: var(--primary-light);
}

.input-group input[type="number"]:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.radio-group {
    display: flex;
    gap: var(--spacing-lg);
}

.radio-group label {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    cursor: pointer;
    font-weight: 500;
    color: var(--text-primary);
}

.radio-group input[type="radio"] {
    width: 18px;
    height: 18px;
    accent-color: var(--primary-color);
    cursor: pointer;
}

/* ============================================
   Buttons
   ============================================ */
.calculate-btn,
.copy-btn {
    width: 100%;
    padding: var(--spacing-md) var(--spacing-xl);
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-hover) 100%);
    border: none;
    border-radius: var(--radius-md);
    color: white;
    font-weight: 700;
    font-size: 1rem;
    cursor: pointer;
    transition: all var(--transition-fast);
    box-shadow: var(--shadow-md);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
}

.calculate-btn:hover,
.copy-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.calculate-btn:active,
.copy-btn:active {
    transform: translateY(0);
    box-shadow: var(--shadow-sm);
}

.copy-btn svg {
    width: 20px;
    height: 20px;
    stroke: white;
    stroke-width: 2;
}

/* ============================================
   Footer
   ============================================ */
.calculator-footer {
    padding: var(--spacing-lg) var(--spacing-xl);
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
}

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 768px) {
    .resistor-calculator-wrapper {
        padding: var(--spacing-md) var(--spacing-sm);
    }
    
    .calculator-header {
        padding: var(--spacing-lg);
    }
    
    .calculator-title {
        font-size: 1.25rem;
    }
    
    .calculator-icon {
        width: 24px;
        height: 24px;
    }
    
    .mode-selector {
        padding: var(--spacing-md);
    }
    
    .mode-btn {
        min-width: 80px;
        font-size: 0.8rem;
        padding: var(--spacing-sm);
    }
    
    .calculator-content {
        padding: var(--spacing-lg);
    }
    
    .color-selectors {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .result-number {
        font-size: 1.5rem;
    }
    
    .utility-tabs {
        flex-direction: column;
    }
    
    .utility-tab {
        border-bottom: none;
        border-left: 3px solid transparent;
    }
    
    .utility-tab.active {
        border-left-color: var(--primary-color);
        border-bottom-color: transparent;
    }
}

@media (max-width: 480px) {
    .calculator-title {
        font-size: 1.1rem;
    }
    
    .color-selectors {
        grid-template-columns: 1fr;
    }
    
    .result-display {
        padding: var(--spacing-md);
    }
    
    .result-number {
        font-size: 1.25rem;
    }
}

/* ============================================
   Accessibility
   ============================================ */
.color-select:focus-visible,
.smd-input:focus-visible,
input[type="number"]:focus-visible,
.calculate-btn:focus-visible,
.copy-btn:focus-visible,
.mode-btn:focus-visible,
.utility-tab:focus-visible,
.theme-toggle:focus-visible {
    outline: 3px solid var(--primary-color);
    outline-offset: 2px;
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}