/* CSS Variables for Color Palette */
:root {
    --primary-color: #05386B;
    --secondary-color: #379683;
    --accent-color: #5CDB95;
    --light-accent: #8EE4AF;
    --background-color: #EDF5E1;
    --text-color: #05386B;
    --text-light: #379683;
    --white: #ffffff;
    --gray-100: #f8f9fa;
    --gray-200: #e9ecef;
    --gray-300: #dee2e6;
    --gray-400: #ced4da;
    --gray-500: #adb5bd;
    --gray-600: #6c757d;
    --gray-700: #495057;
    --gray-800: #343a40;
    --gray-900: #212529;
    --error-color: #dc3545;
    --success-color: #28a745;
    --warning-color: #ffc107;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-xxl: 3rem;
    
    /* Border radius */
    --border-radius-sm: 0.25rem;
    --border-radius-md: 0.5rem;
    --border-radius-lg: 1rem;
    
    /* Shadows */
    --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);
    
    /* Transitions */
    --transition-fast: 0.15s ease-in-out;
    --transition-normal: 0.3s ease-in-out;
    --transition-slow: 0.5s ease-in-out;
}

/* Dark Mode Variables */
[data-theme="dark"] {
    --background-color: #1a1a1a;
    --text-color: #EDF5E1;
    --text-light: #8EE4AF;
    --white: #2d2d2d;
    --gray-100: #2d2d2d;
    --gray-200: #3d3d3d;
    --gray-300: #4d4d4d;
    --gray-400: #5d5d5d;
    --gray-500: #6d6d6d;
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--background-color);
    transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* Layout Components */
.app-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.main-content {
    flex: 1;
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-md);
    width: 100%;
}

/* Header */
.header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--white);
    padding: var(--spacing-xl) var(--spacing-md);
    position: relative;
}

.header__content {
    max-width: 1200px;
    margin: 0 auto;
    text-align: center;
}

.header__title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
}

.header__subtitle {
    font-size: 1.1rem;
    opacity: 0.9;
}

.theme-toggle {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    background: rgba(255, 255, 255, 0.2);
    border: none;
    border-radius: 50%;
    width: 3rem;
    height: 3rem;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition-normal);
    backdrop-filter: blur(10px);
}

.theme-toggle:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: scale(1.1);
}

.theme-toggle__icon {
    font-size: 1.5rem;
}

/* Card Component */
.card {
    background: var(--white);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-normal);
}

.card:hover {
    box-shadow: var(--shadow-lg);
}

.card__title {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: var(--spacing-lg);
    border-bottom: 2px solid var(--accent-color);
    padding-bottom: var(--spacing-sm);
}

/* Form Components */
.form {
    display: grid;
    gap: var(--spacing-lg);
}

.form__group {
    display: flex;
    flex-direction: column;
}

.form__label {
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--text-color);
}

.input {
    padding: var(--spacing-md);
    border: 2px solid var(--gray-300);
    border-radius: var(--border-radius-md);
    font-size: 1rem;
    transition: all var(--transition-fast);
    background: var(--white);
    color: var(--text-color);
}

.input:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(92, 219, 149, 0.1);
}

.input:invalid {
    border-color: var(--error-color);
}

/* Button Components */
.btn {
    padding: var(--spacing-md) var(--spacing-xl);
    border: none;
    border-radius: var(--border-radius-md);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
}

.btn--primary {
    background: linear-gradient(135deg, var(--accent-color), var(--light-accent));
    color: var(--primary-color);
}

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

.btn--secondary {
    background: var(--gray-200);
    color: var(--text-color);
    border: 2px solid var(--gray-300);
}

.btn--secondary:hover {
    background: var(--gray-300);
    transform: translateY(-1px);
}

/* Vehicle Section */
.vehicle-controls {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: var(--spacing-md);
    align-items: end;
}

.vehicle-select {
    min-width: 0;
}

/* Results Section */
.results-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.result-item {
    background: linear-gradient(135deg, var(--background-color), var(--gray-100));
    padding: var(--spacing-lg);
    border-radius: var(--border-radius-md);
    text-align: center;
    border: 2px solid var(--accent-color);
}

.result-item__label {
    display: block;
    font-size: 0.9rem;
    color: var(--text-light);
    margin-bottom: var(--spacing-sm);
    font-weight: 500;
}

.result-item__value {
    display: block;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

/* Chart Section */
.chart-container {
    position: relative;
    height: 300px;
    display: flex;
    align-items: center;
    justify-content: center;
}

#costChart {
    max-width: 100%;
    height: auto;
}

/* Comparison Section */
.comparison-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
}

.comparison-item {
    background: var(--background-color);
    padding: var(--spacing-lg);
    border-radius: var(--border-radius-md);
    border: 2px solid var(--gray-300);
}

.comparison-item__title {
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--primary-color);
}

.comparison-item__data {
    display: grid;
    gap: var(--spacing-sm);
}

.comparison-data {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.comparison-data__label {
    font-size: 0.9rem;
    color: var(--text-light);
}

.comparison-data__value {
    font-weight: 600;
    color: var(--primary-color);
}

/* History Section */
.history-controls {
    margin-bottom: var(--spacing-lg);
    display: flex;
    justify-content: flex-end;
}

.history-list {
    display: grid;
    gap: var(--spacing-md);
}

.history-empty {
    text-align: center;
    color: var(--gray-500);
    font-style: italic;
    padding: var(--spacing-xl);
}

.history-item {
    background: var(--background-color);
    padding: var(--spacing-lg);
    border-radius: var(--border-radius-md);
    border-left: 4px solid var(--accent-color);
    display: grid;
    grid-template-columns: 1fr auto;
    align-items: center;
    gap: var(--spacing-md);
}

.history-item__info {
    display: grid;
    gap: var(--spacing-xs);
}

.history-item__title {
    font-weight: 600;
    color: var(--primary-color);
}

.history-item__details {
    font-size: 0.9rem;
    color: var(--text-light);
}

.history-item__cost {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--secondary-color);
}

.history-item__actions {
    display: flex;
    gap: var(--spacing-sm);
}

.btn--small {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.8rem;
}

.btn--danger {
    background: var(--error-color);
    color: var(--white);
}

.btn--danger:hover {
    background: #c82333;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    backdrop-filter: blur(5px);
}

.modal.modal--open {
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal__content {
    background: var(--white);
    border-radius: var(--border-radius-lg);
    max-width: 500px;
    width: 90%;
    max-height: 90vh;
    overflow-y: auto;
    animation: modalSlideIn 0.3s ease-out;
}

.modal__header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-xl);
    border-bottom: 1px solid var(--gray-200);
}

.modal__title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--primary-color);
}

.modal__close {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--gray-500);
    width: 2rem;
    height: 2rem;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: all var(--transition-fast);
}

.modal__close:hover {
    background: var(--gray-100);
    color: var(--gray-700);
}

.modal .form {
    padding: var(--spacing-xl);
}

.modal__actions {
    display: flex;
    gap: var(--spacing-md);
    justify-content: flex-end;
    margin-top: var(--spacing-lg);
}

/* Footer */
.footer {
    background: var(--primary-color);
    color: var(--white);
    text-align: center;
    padding: var(--spacing-lg);
    margin-top: auto;
}

.footer__text {
    font-size: 0.9rem;
    opacity: 0.9;
}

/* Animations */
@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translateY(-50px) scale(0.9);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

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

.fade-in {
    animation: fadeIn 0.5s ease-out;
}

/* Responsive Design */
@media (max-width: 768px) {
    .header__title {
        font-size: 2rem;
    }
    
    .header__subtitle {
        font-size: 1rem;
    }
    
    .main-content {
        padding: var(--spacing-sm);
    }
    
    .card {
        padding: var(--spacing-lg);
        margin-bottom: var(--spacing-lg);
    }
    
    .vehicle-controls {
        grid-template-columns: 1fr;
        gap: var(--spacing-sm);
    }
    
    .results-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }
    
    .comparison-grid {
        grid-template-columns: 1fr;
    }
    
    .history-item {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .modal__content {
        width: 95%;
        margin: var(--spacing-md);
    }
    
    .modal__actions {
        flex-direction: column;
    }
    
    .theme-toggle {
        top: var(--spacing-sm);
        right: var(--spacing-sm);
        width: 2.5rem;
        height: 2.5rem;
    }
    
    .theme-toggle__icon {
        font-size: 1.2rem;
    }
}

@media (max-width: 480px) {
    .header {
        padding: var(--spacing-lg) var(--spacing-sm);
    }
    
    .header__title {
        font-size: 1.75rem;
    }
    
    .card {
        padding: var(--spacing-md);
    }
    
    .btn {
        width: 100%;
    }
    
    .modal__actions .btn {
        width: auto;
    }
}

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

/* Focus styles for better accessibility */
.btn:focus,
.input:focus,
.theme-toggle:focus {
    outline: 2px solid var(--accent-color);
    outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
        --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
        --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.3);
    }
    
    .card {
        border: 2px solid var(--gray-400);
    }
    
    .input {
        border-width: 3px;
    }
}

/* Print styles */
@media print {
    .theme-toggle,
    .btn,
    .modal {
        display: none !important;
    }
    
    .card {
        box-shadow: none;
        border: 1px solid var(--gray-400);
        page-break-inside: avoid;
    }
    
    .header {
        background: none;
        color: var(--text-color);
    }
}