/* 100xSolutions Calculator - Brand Styles */

/* CSS Reset & Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* 100xSolutions Brand Colors */
    --primary-navy: #0F172A;
    --electric-cyan: #22D3EE;
    --cyan-bright: #38BDF8;
    --neon-green: #22C55E;
    --pure-white: #FFFFFF;
    --surface-dark: #1E293B;
    --surface-elevated: #334155;
    --text-primary: #FFFFFF;
    --text-secondary: #CBD5E1;
    --text-muted: #94A3B8;
    --border-dark: #334155;
    --border-light: #475569;
    --success: #22C55E;
    --warning: #F59E0B;
    --error: #EF4444;
    --info: #38BDF8;
    
    /* Enhanced Shadows & Effects */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.3);
    --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.3), 0 1px 2px -1px rgb(0 0 0 / 0.3);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.3), 0 4px 6px -4px rgb(0 0 0 / 0.3);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.3), 0 8px 10px -6px rgb(0 0 0 / 0.3);
    --glow-cyan: 0 0 20px rgba(34, 211, 238, 0.3);
    --glow-green: 0 0 20px rgba(34, 197, 94, 0.3);
    
    /* Border Radius */
    --border-radius: 8px;
    --border-radius-lg: 12px;
    --border-radius-xl: 16px;
    
    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'SF Pro Display', sans-serif;
    
    /* Transitions */
    --transition-fast: 0.15s ease-out;
    --transition: 0.2s ease-out;
    --transition-slow: 0.3s ease-out;
}

body {
    font-family: var(--font-family);
    background: linear-gradient(135deg, var(--primary-navy) 0%, #1E293B 100%);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    min-height: 100vh;
}

/* Header - 100xSolutions Brand */
.header {
    background: rgba(30, 41, 59, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-dark);
    padding: 1rem 2rem;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-lg);
}

.header-content {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.company-brand {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.company-logo {
    font-size: 1.75rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--electric-cyan), var(--cyan-bright));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.5px;
}

.company-tagline {
    font-size: 0.875rem;
    color: var(--text-muted);
    font-weight: 500;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--electric-cyan), var(--cyan-bright));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.5px;
}

.header-actions {
    display: flex;
    gap: 0.75rem;
}

.icon-btn {
    background: rgba(71, 85, 105, 0.3);
    border: 1px solid var(--border-dark);
    border-radius: var(--border-radius);
    padding: 0.75rem;
    cursor: pointer;
    transition: all var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    width: 2.75rem;
    height: 2.75rem;
    color: var(--text-secondary);
    position: relative;
    overflow: hidden;
}

.icon-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(34, 211, 238, 0.2), transparent);
    transition: left 0.5s;
}

.icon-btn:hover::before {
    left: 100%;
}

.icon-btn:hover {
    background: rgba(34, 211, 238, 0.1);
    border-color: var(--electric-cyan);
    color: var(--electric-cyan);
    box-shadow: var(--glow-cyan);
    transform: translateY(-1px);
}

.icon {
    font-size: 1.125rem;
}

/* Main Calculator Container */
.calculator-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem;
    min-height: calc(100vh - 80px);
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

/* Display Section - Premium Enterprise Style */
.display-section {
    background: rgba(30, 41, 59, 0.8);
    backdrop-filter: blur(20px);
    border: 1px solid var(--border-dark);
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    box-shadow: var(--shadow-xl), var(--glow-cyan);
    position: relative;
    overflow: hidden;
}

.display-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--electric-cyan), transparent);
}

.calc-display {
    background: rgba(15, 23, 42, 0.6);
    border: 1px solid var(--border-light);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    text-align: right;
    min-height: 5rem;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    position: relative;
    overflow: hidden;
}

.calc-display::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(34, 211, 238, 0.05) 0%, transparent 50%, rgba(34, 197, 94, 0.05) 100%);
    pointer-events: none;
}

.expression-display {
    color: var(--text-muted);
    font-size: 1rem;
    font-weight: 500;
    min-height: 1.5rem;
    word-wrap: break-word;
    word-break: break-all;
    letter-spacing: 0.5px;
}

.result-display {
    color: var(--pure-white);
    font-size: 2.5rem;
    font-weight: 700;
    min-height: 3rem;
    word-wrap: break-word;
    word-break: break-all;
    background: linear-gradient(135deg, var(--pure-white), var(--text-primary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-shadow: 0 0 30px rgba(255, 255, 255, 0.3);
}

/* Quick Actions - Premium Style */
.quick-actions {
    display: flex;
    gap: 0.75rem;
    justify-content: flex-end;
}

.action-btn {
    background: rgba(71, 85, 105, 0.3);
    border: 1px solid var(--border-dark);
    border-radius: var(--border-radius);
    padding: 0.75rem 1rem;
    cursor: pointer;
    transition: all var(--transition);
    font-size: 0.875rem;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-secondary);
    position: relative;
    overflow: hidden;
}

.action-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(34, 211, 238, 0.2), transparent);
    transition: left 0.5s;
}

.action-btn:hover::before {
    left: 100%;
}

.action-btn:hover {
    background: rgba(34, 211, 238, 0.1);
    border-color: var(--electric-cyan);
    color: var(--electric-cyan);
    box-shadow: var(--glow-cyan);
    transform: translateY(-1px);
}

/* Tab Navigation - Premium Enterprise Style */
.tab-navigation {
    display: flex;
    background: rgba(30, 41, 59, 0.8);
    backdrop-filter: blur(20px);
    border: 1px solid var(--border-dark);
    border-radius: var(--border-radius-lg);
    padding: 0.5rem;
    box-shadow: var(--shadow-lg);
    overflow-x: auto;
    gap: 0.25rem;
}

.tab-btn {
    flex: 1;
    background: transparent;
    border: 1px solid transparent;
    padding: 1rem 1.5rem;
    cursor: pointer;
    transition: all var(--transition);
    border-radius: var(--border-radius);
    font-weight: 600;
    font-size: 0.875rem;
    color: var(--text-muted);
    white-space: nowrap;
    min-width: max-content;
    position: relative;
    overflow: hidden;
}

.tab-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(34, 211, 238, 0.1), rgba(56, 189, 248, 0.1));
    opacity: 0;
    transition: opacity var(--transition);
}

.tab-btn:hover::before {
    opacity: 1;
}

.tab-btn.active {
    background: linear-gradient(135deg, var(--electric-cyan), var(--cyan-bright));
    color: var(--primary-navy);
    box-shadow: var(--glow-cyan), var(--shadow-lg);
    border-color: var(--electric-cyan);
    font-weight: 700;
}

.tab-btn.active::before {
    opacity: 0;
}

.tab-btn:hover:not(.active) {
    color: var(--electric-cyan);
    border-color: var(--border-light);
    transform: translateY(-1px);
    box-shadow: var(--shadow);
}

/* Calculator Grid - Premium Enterprise Style */
.calculator-grid {
    flex: 1;
    background: rgba(30, 41, 59, 0.6);
    backdrop-filter: blur(20px);
    border: 1px solid var(--border-dark);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-xl);
    overflow: hidden;
    position: relative;
}

.calculator-grid::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(34, 211, 238, 0.03) 0%, transparent 50%, rgba(34, 197, 94, 0.03) 100%);
    pointer-events: none;
}

.tab-content {
    display: none;
    padding: 2rem;
    min-height: 500px;
    position: relative;
    z-index: 1;
}

.tab-content.active {
    display: block;
    animation: fadeInUp 0.4s ease-out;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Button Grid - Premium Style */
.button-grid {
    display: grid;
    gap: 1rem;
    margin-bottom: 2rem;
}

.basic-grid {
    grid-template-columns: repeat(4, 1fr);
    max-width: 450px;
    margin: 0 auto;
}

.scientific-grid {
    grid-template-columns: repeat(4, 1fr);
    max-width: 700px;
    margin: 0 auto;
}

.basic-overlay {
    grid-template-columns: repeat(4, 1fr);
    max-width: 450px;
    margin: 2rem auto 0;
    opacity: 0.7;
}

.calc-btn {
    background: rgba(71, 85, 105, 0.4);
    border: 1px solid var(--border-dark);
    border-radius: var(--border-radius);
    padding: 1.25rem;
    cursor: pointer;
    transition: all var(--transition);
    font-size: 1.25rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 3.5rem;
    user-select: none;
    color: var(--text-primary);
    position: relative;
    overflow: hidden;
    backdrop-filter: blur(10px);
}

.calc-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(34, 211, 238, 0.2), transparent);
    transition: left 0.6s;
}

.calc-btn:hover::before {
    left: 100%;
}

.calc-btn:hover {
    background: rgba(34, 211, 238, 0.1);
    border-color: var(--electric-cyan);
    color: var(--electric-cyan);
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl), var(--glow-cyan);
}

.calc-btn:active {
    transform: translateY(0);
    box-shadow: var(--shadow-lg);
}

.calc-btn.number {
    background: rgba(51, 65, 85, 0.5);
    color: var(--pure-white);
    border-color: var(--border-light);
}

.calc-btn.number:hover {
    background: rgba(34, 211, 238, 0.15);
    color: var(--electric-cyan);
    border-color: var(--electric-cyan);
}

.calc-btn.operator {
    background: linear-gradient(135deg, var(--electric-cyan), var(--cyan-bright));
    color: var(--primary-navy);
    border-color: var(--electric-cyan);
    font-weight: 700;
    box-shadow: var(--glow-cyan);
}

.calc-btn.operator:hover {
    background: linear-gradient(135deg, var(--cyan-bright), var(--electric-cyan));
    box-shadow: var(--glow-cyan), var(--shadow-xl);
    transform: translateY(-3px);
}

.calc-btn.function {
    background: rgba(71, 85, 105, 0.4);
    color: var(--text-secondary);
    border-color: var(--border-dark);
}

.calc-btn.function:hover {
    background: rgba(56, 189, 248, 0.1);
    color: var(--cyan-bright);
    border-color: var(--cyan-bright);
}

.calc-btn.equals {
    background: linear-gradient(135deg, var(--neon-green), #16A34A);
    color: var(--pure-white);
    border-color: var(--neon-green);
    font-weight: 700;
    box-shadow: var(--glow-green);
}

.calc-btn.equals:hover {
    background: linear-gradient(135deg, #16A34A, var(--neon-green));
    box-shadow: var(--glow-green), var(--shadow-xl);
    transform: translateY(-3px);
}

.calc-btn.constant {
    background: linear-gradient(135deg, var(--warning), #F97316);
    color: var(--pure-white);
    border-color: var(--warning);
    font-weight: 700;
}

.calc-btn.constant:hover {
    background: linear-gradient(135deg, #F97316, var(--warning));
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
}

.calc-btn.primary {
    background: linear-gradient(135deg, var(--electric-cyan), var(--cyan-bright));
    color: var(--primary-navy);
    border-color: var(--electric-cyan);
    grid-column: span 2;
    font-weight: 700;
    box-shadow: var(--glow-cyan);
}

.calc-btn.primary:hover {
    background: linear-gradient(135deg, var(--cyan-bright), var(--electric-cyan));
    box-shadow: var(--glow-cyan), var(--shadow-xl);
    transform: translateY(-3px);
}

.calc-btn.secondary {
    background: rgba(71, 85, 105, 0.3);
    color: var(--text-muted);
    border-color: var(--border-dark);
}

.calc-btn.secondary:hover {
    background: rgba(34, 211, 238, 0.1);
    color: var(--electric-cyan);
    border-color: var(--electric-cyan);
}

/* Financial Calculator - Premium Enterprise Style */
.financial-section {
    background: rgba(51, 65, 85, 0.4);
    backdrop-filter: blur(20px);
    border: 1px solid var(--border-dark);
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    margin-bottom: 1.5rem;
    position: relative;
    overflow: hidden;
}

.financial-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--electric-cyan), transparent);
}

.financial-section h3 {
    color: var(--pure-white);
    margin-bottom: 1.5rem;
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--pure-white), var(--electric-cyan));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.input-group {
    margin-bottom: 1.5rem;
}

.input-group label {
    display: block;
    margin-bottom: 0.75rem;
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.875rem;
    letter-spacing: 0.5px;
}

.input-group input,
.input-group select {
    width: 100%;
    padding: 1rem;
    border: 1px solid var(--border-dark);
    border-radius: var(--border-radius);
    background: rgba(15, 23, 42, 0.6);
    color: var(--text-primary);
    font-size: 1rem;
    font-weight: 500;
    transition: all var(--transition);
    backdrop-filter: blur(10px);
}

.input-group input:focus,
.input-group select:focus {
    outline: none;
    border-color: var(--electric-cyan);
    box-shadow: var(--glow-cyan), 0 0 0 3px rgba(34, 211, 238, 0.1);
    background: rgba(15, 23, 42, 0.8);
}

.input-group input::placeholder {
    color: var(--text-muted);
    font-weight: 400;
}

input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    height: 8px;
    background: linear-gradient(90deg, var(--border-dark), var(--surface-elevated));
    border-radius: 4px;
    outline: none;
    border: 1px solid var(--border-dark);
    position: relative;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 24px;
    height: 24px;
    background: linear-gradient(135deg, var(--electric-cyan), var(--cyan-bright));
    border-radius: 50%;
    cursor: pointer;
    box-shadow: var(--glow-cyan), var(--shadow-lg);
    border: 2px solid var(--pure-white);
    transition: all var(--transition);
}

input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.1);
    box-shadow: var(--glow-cyan), var(--shadow-xl);
}

input[type="range"]::-moz-range-thumb {
    width: 24px;
    height: 24px;
    background: linear-gradient(135deg, var(--electric-cyan), var(--cyan-bright));
    border-radius: 50%;
    cursor: pointer;
    border: 2px solid var(--pure-white);
    box-shadow: var(--glow-cyan), var(--shadow-lg);
    transition: all var(--transition);
}

input[type="range"]::-moz-range-thumb:hover {
    transform: scale(1.1);
    box-shadow: var(--glow-cyan), var(--shadow-xl);
}

.range-value {
    display: inline-block;
    margin-left: 1rem;
    font-weight: 700;
    color: var(--electric-cyan);
    font-size: 1rem;
    background: rgba(34, 211, 238, 0.1);
    padding: 0.25rem 0.75rem;
    border-radius: var(--border-radius);
    border: 1px solid var(--electric-cyan);
}

.results {
    background: rgba(15, 23, 42, 0.8);
    backdrop-filter: blur(20px);
    border: 1px solid var(--electric-cyan);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    margin: 1.5rem 0;
    font-family: 'SF Mono', 'Monaco', 'Consolas', 'Courier New', monospace;
    font-size: 0.875rem;
    line-height: 1.6;
    color: var(--text-primary);
    box-shadow: var(--glow-cyan), var(--shadow-lg);
    position: relative;
    overflow: hidden;
}

.results::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--electric-cyan), transparent);
}

/* Converter - Premium Enterprise Style */
.converter-section {
    background: rgba(51, 65, 85, 0.4);
    backdrop-filter: blur(20px);
    border: 1px solid var(--border-dark);
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    margin-bottom: 1.5rem;
    position: relative;
    overflow: hidden;
}

.converter-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--electric-cyan), transparent);
}

.converter-section h3 {
    color: var(--pure-white);
    margin-bottom: 1.5rem;
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--pure-white), var(--electric-cyan));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.converter-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    margin-bottom: 2rem;
}

/* Utility - Premium Enterprise Style */
.utility-section {
    background: rgba(51, 65, 85, 0.4);
    backdrop-filter: blur(20px);
    border: 1px solid var(--border-dark);
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    margin-bottom: 1.5rem;
    position: relative;
    overflow: hidden;
}

.utility-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--electric-cyan), transparent);
}

.utility-section h3 {
    color: var(--pure-white);
    margin-bottom: 1.5rem;
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--pure-white), var(--electric-cyan));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.tip-card {
    background: rgba(15, 23, 42, 0.8);
    backdrop-filter: blur(20px);
    border: 1px solid var(--electric-cyan);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    font-style: italic;
    color: var(--text-secondary);
    text-align: center;
    position: relative;
    overflow: hidden;
    box-shadow: var(--glow-cyan), var(--shadow-lg);
}

.tip-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--electric-cyan), transparent);
}

/* History Sidebar - Premium Enterprise Style */
.history-sidebar {
    position: fixed;
    top: 0;
    right: -450px;
    width: 450px;
    height: 100vh;
    background: rgba(30, 41, 59, 0.95);
    backdrop-filter: blur(20px);
    border-left: 1px solid var(--border-dark);
    box-shadow: var(--shadow-xl);
    transition: right var(--transition-slow);
    z-index: 1000;
    display: flex;
    flex-direction: column;
}

.history-sidebar.open {
    right: 0;
}

.history-header {
    padding: 2rem;
    border-bottom: 1px solid var(--border-dark);
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: rgba(51, 65, 85, 0.3);
}

.history-header h3 {
    color: var(--pure-white);
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--pure-white), var(--electric-cyan));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin: 0;
}

.history-list {
    flex: 1;
    overflow-y: auto;
    padding: 1.5rem;
}

.history-item {
    background: rgba(71, 85, 105, 0.3);
    border: 1px solid var(--border-dark);
    border-radius: var(--border-radius);
    padding: 1.25rem;
    margin-bottom: 1rem;
    cursor: pointer;
    transition: all var(--transition);
    position: relative;
    overflow: hidden;
    backdrop-filter: blur(10px);
}

.history-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(34, 211, 238, 0.1), transparent);
    transition: left 0.5s;
}

.history-item:hover::before {
    left: 100%;
}

.history-item:hover {
    background: rgba(34, 211, 238, 0.1);
    border-color: var(--electric-cyan);
    box-shadow: var(--glow-cyan), var(--shadow-lg);
    transform: translateY(-2px);
}

.history-expression {
    color: var(--text-muted);
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: 0.5rem;
    font-family: 'SF Mono', 'Monaco', 'Consolas', monospace;
}

.history-result {
    color: var(--pure-white);
    font-weight: 700;
    font-size: 1.125rem;
    background: linear-gradient(135deg, var(--pure-white), var(--electric-cyan));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 0.5rem;
}

.history-time {
    color: var(--text-muted);
    font-size: 0.75rem;
    font-weight: 400;
}

.history-actions {
    padding: 1.5rem;
    border-top: 1px solid var(--border-dark);
    display: flex;
    gap: 1rem;
    background: rgba(51, 65, 85, 0.2);
}

.close-btn {
    background: rgba(71, 85, 105, 0.3);
    border: 1px solid var(--border-dark);
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-muted);
    padding: 0.5rem;
    border-radius: var(--border-radius);
    transition: all var(--transition);
    width: 2.5rem;
    height: 2.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

.close-btn:hover {
    background: rgba(34, 211, 238, 0.1);
    border-color: var(--electric-cyan);
    color: var(--electric-cyan);
    box-shadow: var(--glow-cyan);
    transform: scale(1.1);
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 2000;
    align-items: center;
    justify-content: center;
}

.modal.open {
    display: flex;
}

.modal-content {
    background: var(--surface);
    border-radius: var(--border-radius-lg);
    max-width: 90vw;
    max-height: 90vh;
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.modal-header {
    padding: 1rem;
    border-bottom: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-body {
    padding: 1rem;
}

.export-options {
    margin-top: 1rem;
    display: flex;
    gap: 0.5rem;
    justify-content: center;
}

#graphCanvas {
    max-width: 100%;
    max-height: 400px;
}

/* Voice Input Button - Premium Style */
.voice-btn {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 4rem;
    height: 4rem;
    background: linear-gradient(135deg, var(--electric-cyan), var(--cyan-bright));
    color: var(--primary-navy);
    border: 2px solid var(--pure-white);
    border-radius: 50%;
    cursor: pointer;
    box-shadow: var(--glow-cyan), var(--shadow-xl);
    transition: all var(--transition);
    z-index: 100;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
}

.voice-btn:hover {
    background: linear-gradient(135deg, var(--cyan-bright), var(--electric-cyan));
    transform: scale(1.1);
    box-shadow: var(--glow-cyan), var(--shadow-xl);
}

.voice-btn.listening {
    background: linear-gradient(135deg, var(--neon-green), #16A34A);
    color: var(--pure-white);
    animation: pulse 1.5s infinite;
    box-shadow: var(--glow-green), var(--shadow-xl);
}

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

/* Footer - 100xSolutions Enterprise Branding */
.footer {
    background: rgba(15, 23, 42, 0.95);
    backdrop-filter: blur(20px);
    border-top: 1px solid var(--border-dark);
    margin-top: 4rem;
    position: relative;
    overflow: hidden;
}

.footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--electric-cyan), transparent);
}

.footer-content {
    max-width: 1400px;
    margin: 0 auto;
    padding: 3rem 2rem 2rem;
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 3rem;
}

.footer-section h4 {
    color: var(--pure-white);
    font-size: 1.125rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    background: linear-gradient(135deg, var(--pure-white), var(--electric-cyan));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.footer-brand {
    margin-bottom: 1.5rem;
}

.footer-logo {
    font-size: 1.75rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--electric-cyan), var(--cyan-bright));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.5px;
    margin-bottom: 0.5rem;
}

.footer-tagline {
    font-size: 0.875rem;
    color: var(--text-muted);
    font-weight: 500;
    letter-spacing: 0.5px;
}

.footer-description {
    color: var(--text-secondary);
    line-height: 1.6;
    font-size: 0.875rem;
    margin: 0;
}

.footer-links {
    list-style: none;
    padding: 0;
    margin: 0;
}

.footer-links li {
    margin-bottom: 0.75rem;
}

.footer-links a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.875rem;
    font-weight: 500;
    transition: all var(--transition);
    position: relative;
    display: inline-block;
}

.footer-links a::before {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 1px;
    background: linear-gradient(90deg, var(--electric-cyan), var(--cyan-bright));
    transition: width var(--transition);
}

.footer-links a:hover {
    color: var(--electric-cyan);
    transform: translateX(4px);
}

.footer-links a:hover::before {
    width: 100%;
}

.footer-bottom {
    background: rgba(51, 65, 85, 0.3);
    border-top: 1px solid var(--border-dark);
    padding: 1.5rem 0;
}

.footer-bottom-content {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.copyright {
    color: var(--text-muted);
    font-size: 0.875rem;
    font-weight: 500;
    margin: 0;
}

.footer-tech {
    display: flex;
    gap: 0.75rem;
}

.tech-badge {
    background: rgba(34, 211, 238, 0.1);
    border: 1px solid var(--electric-cyan);
    color: var(--electric-cyan);
    padding: 0.25rem 0.75rem;
    border-radius: var(--border-radius);
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.5px;
}

/* FAQ Section - 100xSolutions Enterprise Support */
.faq-section {
    background: rgba(30, 41, 59, 0.6);
    backdrop-filter: blur(20px);
    border: 1px solid var(--border-dark);
    border-radius: var(--border-radius-lg);
    padding: 3rem 2rem;
    margin: 4rem 0;
    position: relative;
    overflow: hidden;
}

.faq-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--electric-cyan), transparent);
}

.faq-container {
    max-width: 1000px;
    margin: 0 auto;
}

.faq-header {
    text-align: center;
    margin-bottom: 3rem;
}

.faq-header h2 {
    color: var(--pure-white);
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, var(--pure-white), var(--electric-cyan));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.faq-header p {
    color: var(--text-secondary);
    font-size: 1.125rem;
    font-weight: 500;
    margin: 0;
}

.faq-grid {
    display: grid;
    gap: 1.5rem;
}

.faq-item {
    background: rgba(51, 65, 85, 0.4);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-dark);
    border-radius: var(--border-radius);
    overflow: hidden;
    transition: all var(--transition);
}

.faq-item:hover {
    background: rgba(71, 85, 105, 0.5);
    border-color: var(--electric-cyan);
    box-shadow: var(--glow-cyan), var(--shadow-lg);
}

.faq-question {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem;
    cursor: pointer;
    transition: all var(--transition);
    position: relative;
}

.faq-question:hover {
    background: rgba(34, 211, 238, 0.05);
}

.faq-question h3 {
    color: var(--pure-white);
    font-size: 1.125rem;
    font-weight: 600;
    margin: 0;
    flex: 1;
    padding-right: 1rem;
}

.faq-toggle {
    color: var(--electric-cyan);
    font-size: 1.5rem;
    font-weight: 300;
    transition: transform var(--transition);
    min-width: 2rem;
    text-align: center;
}

.faq-item.active .faq-toggle {
    transform: rotate(45deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-slow), padding var(--transition-slow);
    background: rgba(15, 23, 42, 0.3);
}

.faq-item.active .faq-answer {
    max-height: 500px;
    padding: 1.5rem;
}

.faq-answer p {
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 1rem;
}

.faq-answer p:last-child {
    margin-bottom: 0;
}

.faq-answer ul {
    color: var(--text-secondary);
    line-height: 1.6;
    padding-left: 1.5rem;
    margin: 1rem 0;
}

.faq-answer li {
    margin-bottom: 0.5rem;
}

.faq-answer strong {
    color: var(--electric-cyan);
    font-weight: 600;
}

/* FAQ Navigation Links */
.faq-nav {
    text-align: center;
    margin: 2rem 0;
}

.faq-nav a {
    display: inline-block;
    background: linear-gradient(135deg, var(--electric-cyan), var(--cyan-bright));
    color: var(--primary-navy);
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 600;
    transition: all var(--transition);
    margin: 0 0.5rem;
}

.faq-nav a:hover {
    background: linear-gradient(135deg, var(--cyan-bright), var(--electric-cyan));
    transform: translateY(-2px);
    box-shadow: var(--glow-cyan), var(--shadow-lg);
}

/* Responsive Design */
@media (max-width: 768px) {
    .calculator-container {
        padding: 0.5rem;
    }
    
    .display-section {
        padding: 1rem;
    }
    
    .calc-display {
        padding: 0.75rem;
    }
    
    .result-display {
        font-size: 1.5rem;
    }
    
    .tab-navigation {
        flex-wrap: wrap;
    }
    
    .tab-btn {
        font-size: 0.875rem;
        padding: 0.5rem 0.75rem;
    }
    
    .calculator-grid {
        margin: 0 -0.5rem;
    }
    
    .tab-content {
        padding: 1rem;
    }
    
    .calc-btn {
        padding: 0.75rem;
        font-size: 1rem;
        min-height: 2.5rem;
    }
    
    .converter-grid {
        grid-template-columns: 1fr;
    }
    
    .financial-section,
    .converter-section,
    .utility-section {
        padding: 1rem;
    }
    
    .history-sidebar {
        width: 100%;
        right: -100%;
    }
    
    .modal-content {
        max-width: 95vw;
        max-height: 95vh;
    }
    
    .voice-btn {
        bottom: 1rem;
        right: 1rem;
        width: 3rem;
        height: 3rem;
        font-size: 1rem;
    }
    
    /* Footer Mobile Styles */
    .footer-content {
        grid-template-columns: 1fr;
        gap: 2rem;
        padding: 2rem 1rem;
        text-align: center;
    }
    
    .footer-bottom-content {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
        padding: 0 1rem;
    }
    
    .footer-tech {
        justify-content: center;
    }
    
    .company-brand {
        flex-direction: column;
        gap: 0.5rem;
        text-align: center;
    }
    
    .header-content {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .header-content {
        padding: 0 0.5rem;
    }
    
    .logo {
        font-size: 1.25rem;
    }
    
    .header-actions {
        gap: 0.25rem;
    }
    
    .icon-btn {
        width: 2rem;
        height: 2rem;
        padding: 0.25rem;
    }
    
    .basic-grid,
    .scientific-grid {
        grid-template-columns: repeat(4, 1fr);
        gap: 0.5rem;
    }
    
    .calc-btn {
        padding: 0.5rem;
        font-size: 0.875rem;
        min-height: 2.25rem;
    }
    
    .input-group input,
    .input-group select {
        padding: 0.5rem;
        font-size: 0.875rem;
    }
}

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

/* High contrast mode */
@media (prefers-contrast: high) {
    :root {
        --border: #000000;
        --text-secondary: #000000;
    }
}

/* Print styles */
@media print {
    .header,
    .tab-navigation,
    .calculator-grid,
    .voice-btn,
    .history-sidebar {
        display: none !important;
    }
    
    .calculator-container {
        padding: 0;
        max-width: none;
    }
    
    .display-section {
        box-shadow: none;
        border: 1px solid #000;
    }
}

/* Loading states */
.loading {
    opacity: 0.6;
    pointer-events: none;
    position: relative;
}

.loading::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 20px;
    height: 20px;
    margin: -10px 0 0 -10px;
    border: 2px solid var(--border);
    border-top: 2px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Focus styles for keyboard navigation */
.calc-btn:focus,
.tab-btn:focus,
.icon-btn:focus,
input:focus,
select:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* Currency Converter Enhancements */
.converter-currency-section {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--border-radius-lg);
    padding: 1.5rem;
    margin-bottom: 1rem;
}

.converter-currency-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--border);
}

.converter-currency-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
}

.converter-currency-actions {
    display: flex;
    gap: 0.5rem;
}

.btn-live-rates {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
}

.btn-live-rates:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
}

.btn-live-rates:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

.btn-live-rates .spinner {
    width: 14px;
    height: 14px;
    border: 2px solid transparent;
    border-top: 2px solid currentColor;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

/* Currency Rates Status */
.rates-status {
    margin-bottom: 1rem;
    padding: 0.75rem;
    border-radius: var(--border-radius);
    background: var(--surface-elevated);
    border: 1px solid var(--border);
}

.status-success {
    color: var(--success);
    background: rgba(16, 185, 129, 0.1);
    border-color: var(--success);
}

.status-warning {
    color: var(--warning);
    background: rgba(245, 158, 11, 0.1);
    border-color: var(--warning);
}

.status-error {
    color: var(--error);
    background: rgba(239, 68, 68, 0.1);
    border-color: var(--error);
}

.status-info {
    color: var(--primary-color);
    background: rgba(59, 130, 246, 0.1);
    border-color: var(--primary-color);
}

.rates-status .status-icon {
    margin-right: 0.5rem;
    font-size: 1rem;
}

.rates-status .status-message {
    font-weight: 500;
    margin-right: 1rem;
}

.rates-status .status-time {
    font-size: 0.75rem;
    opacity: 0.7;
    font-style: italic;
}

/* Enhanced Currency Display */
.currency-option {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem;
}

.currency-flag {
    font-size: 1.2rem;
    width: 24px;
    text-align: center;
}

.currency-info {
    flex: 1;
}

.currency-code {
    font-weight: 600;
    color: var(--text-primary);
}

.currency-name {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Live Rates Indicator */
.live-rates-indicator {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.25rem 0.5rem;
    background: var(--success);
    color: white;
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 500;
    animation: pulse 2s infinite;
}

.live-rates-indicator .pulse-dot {
    width: 6px;
    height: 6px;
    background: white;
    border-radius: 50%;
    animation: pulse-dot 1.5s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.7; }
}

@keyframes pulse-dot {
    0%, 100% { transform: scale(1); opacity: 1; }
    50% { transform: scale(0.8); opacity: 0.7; }
}

/* Error states */
.error {
    border-color: var(--error) !important;
    box-shadow: 0 0 0 3px rgb(220 38 38 / 0.1) !important;
}

.error-message {
    color: var(--error);
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

/* Success states */
.success {
    border-color: var(--success) !important;
    box-shadow: 0 0 0 3px rgb(5 150 105 / 0.1) !important;
}

/* Animations */
.slide-in {
    animation: slideIn 0.3s ease-out;
}

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

.fade-in {
    animation: fadeIn 0.3s ease-out;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}