/* Color Palette Variables */
:root {
    --primary-color: #00ADB5;
    --secondary-color: #393E46;
    --dark-color: #222831;
    --light-color: #EEEEEE;
    --accent-color: #FFD369;
    --text-dark: #222831;
    --text-light: #EEEEEE;
    --border-radius: 8px;
    --box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

/* Dark Mode Variables */
.dark-mode {
    --bs-body-bg: #222831;
    --bs-body-color: #EEEEEE;
    --bs-border-color: #393E46;
}

/* Base Styles */
* {
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    transition: var(--transition);
    min-height: 100vh;
    background: linear-gradient(135deg, var(--light-color) 0%, #f8f9fa 100%);
}

.dark-mode body {
    background: linear-gradient(135deg, var(--dark-color) 0%, var(--secondary-color) 100%);
}

/* Header Styles */
header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--primary-color) !important;
}

.dark-mode header {
    background: rgba(34, 40, 49, 0.95);
    border-bottom-color: var(--primary-color) !important;
}

.text-primary {
    color: var(--primary-color) !important;
    font-weight: 600;
    letter-spacing: -0.5px;
}

/* Calculator Display */
.calculator-display {
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 1.5rem;
    margin-bottom: 1rem;
    border: 2px solid var(--primary-color);
    position: relative;
    overflow: hidden;
}

.dark-mode .calculator-display {
    background: var(--secondary-color);
    border-color: var(--primary-color);
}

.expression-display {
    font-size: 1.2rem;
    font-weight: 500;
    color: var(--text-dark);
    min-height: 1.5rem;
    word-break: break-all;
    overflow-x: auto;
    white-space: nowrap;
    padding-bottom: 0.5rem;
}

.dark-mode .expression-display {
    color: var(--text-light);
}

.result-display {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
    min-height: 2.5rem;
    overflow-x: auto;
    white-space: nowrap;
}

/* Calculator Buttons */
.calc-btn {
    height: 60px;
    font-size: 1.1rem;
    font-weight: 600;
    border-radius: var(--border-radius);
    transition: var(--transition);
    border: 1px solid transparent;
    position: relative;
    overflow: hidden;
}

.calc-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.calc-btn:active {
    transform: translateY(0);
}

/* Button Variants */
.number-btn {
    background: white !important;
    color: var(--text-dark) !important;
    border-color: var(--light-color) !important;
}

.dark-mode .number-btn {
    background: var(--secondary-color) !important;
    color: var(--text-light) !important;
    border-color: var(--dark-color) !important;
}

.operator-btn {
    background: var(--primary-color) !important;
    color: white !important;
    border-color: var(--primary-color) !important;
}

.operator-btn:hover {
    background: #008a91 !important;
}

.btn-danger {
    background: #dc3545 !important;
    border-color: #dc3545 !important;
}

.btn-warning {
    background: var(--accent-color) !important;
    color: var(--text-dark) !important;
    border-color: var(--accent-color) !important;
}

.btn-secondary {
    background: var(--secondary-color) !important;
    color: var(--text-light) !important;
    border-color: var(--secondary-color) !important;
}

.btn-success {
    background: #28a745 !important;
    border-color: #28a745 !important;
    font-size: 1.3rem !important;
    font-weight: 700 !important;
}

.btn-info {
    background: var(--accent-color) !important;
    color: var(--text-dark) !important;
    border-color: var(--accent-color) !important;
}

/* Scientific Functions */
.scientific-functions {
    animation: slideDown 0.3s ease;
}

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

/* Memory Functions */
.memory-functions .calc-btn {
    height: 45px;
    font-size: 0.9rem;
}

/* Mode Toggle */
.btn-group .btn-check:checked + .btn {
    background-color: var(--primary-color) !important;
    border-color: var(--primary-color) !important;
    color: white !important;
}

/* History List */
.history-list {
    max-height: 300px;
    overflow-y: auto;
}

.history-item {
    background: white;
    border-radius: var(--border-radius);
    padding: 0.75rem;
    margin-bottom: 0.5rem;
    border-left: 3px solid var(--primary-color);
    cursor: pointer;
    transition: var(--transition);
}

.dark-mode .history-item {
    background: var(--secondary-color);
}

.history-item:hover {
    background: var(--light-color);
    transform: translateX(5px);
}

.dark-mode .history-item:hover {
    background: var(--dark-color);
}

.history-expression {
    font-size: 0.9rem;
    color: var(--text-dark);
    margin-bottom: 0.25rem;
}

.dark-mode .history-expression {
    color: var(--text-light);
}

.history-result {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 0.25rem;
}

.history-time {
    font-size: 0.75rem;
    color: #6c757d;
}

/* Offcanvas Customization */
.offcanvas {
    background: white;
}

.dark-mode .offcanvas {
    background: var(--secondary-color);
    color: var(--text-light);
}

.offcanvas-header {
    border-bottom: 1px solid var(--primary-color);
}

/* Modal Customization */
.modal-content {
    border-radius: var(--border-radius);
    border: 1px solid var(--primary-color);
}

.dark-mode .modal-content {
    background: var(--secondary-color);
    color: var(--text-light);
}

.modal-header {
    border-bottom: 1px solid var(--primary-color);
}

.dark-mode .modal-header {
    border-bottom-color: var(--primary-color);
}

/* Form Controls */
.form-check-input:checked {
    background-color: var(--primary-color);
    border-color: var(--primary-color);
}

.form-check-input:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 0.25rem rgba(0, 173, 181, 0.25);
}

/* Accordion */
.accordion-button {
    font-size: 0.9rem;
}

.accordion-button:not(.collapsed) {
    background-color: var(--primary-color);
    color: white;
}

.accordion-button:focus {
    box-shadow: 0 0 0 0.25rem rgba(0, 173, 181, 0.25);
}

/* Ad Banner */
.ad-banner {
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(5px);
}

.dark-mode .ad-banner {
    background: rgba(57, 62, 70, 0.8);
}

/* Footer */
footer {
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
}

.dark-mode footer {
    background: rgba(34, 40, 49, 0.9);
}

/* Responsive Design */
@media (max-width: 576px) {
    .calc-btn {
        height: 55px;
        font-size: 1rem;
    }
    
    .expression-display {
        font-size: 1rem;
    }
    
    .result-display {
        font-size: 1.5rem;
    }
    
    .calculator-display {
        padding: 1rem;
    }
    
    .scientific-functions .calc-btn {
        height: 45px;
        font-size: 0.8rem;
    }
    
    .memory-functions .calc-btn {
        height: 40px;
        font-size: 0.8rem;
    }
}

@media (max-width: 400px) {
    .calc-btn {
        height: 50px;
        font-size: 0.9rem;
    }
    
    .scientific-functions .calc-btn {
        height: 40px;
        font-size: 0.7rem;
    }
    
    .memory-functions .calc-btn {
        height: 35px;
        font-size: 0.7rem;
    }
}

/* Loading Animation */
.loading {
    opacity: 0.6;
    pointer-events: none;
}

/* Error State */
.error {
    color: #dc3545 !important;
    animation: shake 0.5s ease-in-out;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    75% { transform: translateX(5px); }
}

/* Success Animation */
.success-flash {
    animation: flash 0.3s ease-in-out;
}

@keyframes flash {
    0%, 100% { background-color: transparent; }
    50% { background-color: rgba(40, 167, 69, 0.3); }
}

/* Button Press Animation */
.btn-pressed {
    animation: btnPress 0.1s ease-in-out;
}

@keyframes btnPress {
    0% { transform: scale(1); }
    50% { transform: scale(0.95); }
    100% { transform: scale(1); }
}

/* Scrollbar Styling */
::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}

::-webkit-scrollbar-track {
    background: var(--light-color);
}

.dark-mode ::-webkit-scrollbar-track {
    background: var(--dark-color);
}

::-webkit-scrollbar-thumb {
    background: var(--primary-color);
    border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
    background: #008a91;
}

/* Utility Classes */
.text-gradient {
    background: linear-gradient(45deg, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.glass-effect {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.dark-mode .glass-effect {
    background: rgba(0, 0, 0, 0.2);
    border-color: rgba(255, 255, 255, 0.1);
}

/* Focus Styles for Accessibility */
.calc-btn:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

.btn:focus {
    box-shadow: 0 0 0 0.25rem rgba(0, 173, 181, 0.25);
}

/* High Contrast Mode Support */
@media (prefers-contrast: high) {
    .calc-btn {
        border: 2px solid currentColor;
    }
}

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

/* Print Styles */
@media print {
    .calculator-display {
        box-shadow: none;
        border: 1px solid #000;
    }
    
    .calc-btn {
        box-shadow: none;
        border: 1px solid #000;
    }
    
    header, footer, .offcanvas, .modal {
        display: none;
    }
}