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

:root {
    /* Color Palette */
    --color-primary: #F8B195;
    --color-secondary: #F67280;
    --color-tertiary: #C06C84;
    --color-quaternary: #6C5B7B;
    --color-quinary: #355C7D;
    
    /* Light Theme */
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-card: #ffffff;
    --text-primary: #2c3e50;
    --text-secondary: #6c757d;
    --text-muted: #adb5bd;
    --border-color: #e9ecef;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 4px 20px rgba(0, 0, 0, 0.15);
    
    /* Typography */
    --font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;
    
    /* 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: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    /* Transitions */
    --transition: all 0.3s ease;
}

/* Dark Theme */
[data-theme="dark"] {
    --bg-primary: #1a1a1a;
    --bg-secondary: #2d2d2d;
    --bg-card: #2d2d2d;
    --text-primary: #ffffff;
    --text-secondary: #b0b0b0;
    --text-muted: #808080;
    --border-color: #404040;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
    --shadow-hover: 0 4px 20px rgba(0, 0, 0, 0.4);
}

/* Base Styles */
html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    transition: var(--transition);
}

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

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.main {
    flex: 1;
    padding: var(--spacing-xl) 0;
}

/* Utility Classes */
.hidden {
    display: none !important;
}

.text-center {
    text-align: center;
}

.text-right {
    text-align: right;
}

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }

/* Header */
.header {
    background: linear-gradient(135deg, var(--color-quinary), var(--color-quaternary));
    color: white;
    padding: var(--spacing-xl) 0;
    position: relative;
}

.header__container {
    position: relative;
    text-align: center;
}

.header__title {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
}

.header__subtitle {
    font-size: var(--font-size-lg);
    opacity: 0.9;
}

/* Theme Toggle */
.theme-toggle {
    position: absolute;
    top: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.2);
    border: none;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition);
}

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

.theme-toggle__icon {
    font-size: var(--font-size-xl);
}

/* Section Titles */
.section__title {
    font-size: var(--font-size-2xl);
    font-weight: 600;
    margin-bottom: var(--spacing-lg);
    color: var(--color-quinary);
}

/* Forms */
.trip-form,
.expense-form {
    background: var(--bg-card);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    margin-bottom: var(--spacing-xl);
}

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

.form-label {
    display: block;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.form-input,
.form-select {
    width: 100%;
    padding: var(--spacing-md);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: var(--font-size-base);
    background: var(--bg-primary);
    color: var(--text-primary);
    transition: var(--transition);
}

.form-input:focus,
.form-select:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(248, 177, 149, 0.1);
}

.form-error {
    display: block;
    color: var(--color-secondary);
    font-size: var(--font-size-sm);
    margin-top: var(--spacing-xs);
}

/* Expense Form Row */
.expense-form__row {
    display: grid;
    grid-template-columns: 1fr 1fr 2fr auto;
    gap: var(--spacing-md);
    align-items: end;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-md) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-md);
    font-size: var(--font-size-base);
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: var(--transition);
    white-space: nowrap;
}

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

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

.btn--secondary {
    background: var(--bg-card);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

.btn--secondary:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
}

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

.btn--danger:hover {
    background: var(--color-tertiary);
}

/* Budget Overview */
.budget-overview {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-2xl);
}

.budget-card {
    background: var(--bg-card);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    text-align: center;
    transition: var(--transition);
}

.budget-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-hover);
}

.budget-card__title {
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.budget-card__value {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: var(--color-quinary);
}

.budget-card__value--spent {
    color: var(--color-secondary);
}

/* Daily Expenses */
.daily-expenses {
    background: var(--bg-card);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    margin-bottom: var(--spacing-2xl);
}

.daily-expenses__header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-lg);
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.day-selector {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.current-day {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--color-quinary);
    min-width: 80px;
    text-align: center;
}

/* Expenses List */
.expenses-list {
    margin: var(--spacing-xl) 0;
}

.expenses-list__empty {
    text-align: center;
    color: var(--text-muted);
    font-style: italic;
    padding: var(--spacing-xl);
}

.expense-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-sm);
    transition: var(--transition);
}

.expense-item:hover {
    background: var(--bg-secondary);
    border-color: var(--color-primary);
}

.expense-item__info {
    flex: 1;
}

.expense-item__category {
    font-weight: 600;
    color: var(--color-quinary);
    font-size: var(--font-size-sm);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.expense-item__description {
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
    margin-top: var(--spacing-xs);
}

.expense-item__amount {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--color-secondary);
    margin-right: var(--spacing-md);
}

.expense-item__delete {
    background: none;
    border: none;
    color: var(--color-secondary);
    cursor: pointer;
    padding: var(--spacing-sm);
    border-radius: var(--radius-sm);
    transition: var(--transition);
}

.expense-item__delete:hover {
    background: var(--color-secondary);
    color: white;
}

/* Daily Summary */
.daily-summary {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-lg);
    padding: var(--spacing-lg);
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
    border: 2px solid var(--border-color);
}

.daily-summary__item {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.daily-summary__label {
    font-weight: 600;
    color: var(--text-secondary);
}

.daily-summary__value {
    font-size: var(--font-size-lg);
    font-weight: 700;
    color: var(--color-quinary);
}

/* Chart Section */
.chart-section {
    background: var(--bg-card);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    margin-bottom: var(--spacing-2xl);
}

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

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

/* Actions */
.actions {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
}

/* Alerts */
.alert-container {
    position: fixed;
    top: var(--spacing-lg);
    right: var(--spacing-lg);
    z-index: 1000;
    max-width: 400px;
}

.alert {
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-sm);
    box-shadow: var(--shadow);
    animation: slideIn 0.3s ease;
    position: relative;
}

.alert--success {
    background: #d4edda;
    color: #155724;
    border-left: 4px solid #28a745;
}

.alert--warning {
    background: #fff3cd;
    color: #856404;
    border-left: 4px solid #ffc107;
}

.alert--error {
    background: #f8d7da;
    color: #721c24;
    border-left: 4px solid #dc3545;
}

.alert__close {
    position: absolute;
    top: var(--spacing-sm);
    right: var(--spacing-md);
    background: none;
    border: none;
    font-size: var(--font-size-lg);
    cursor: pointer;
    opacity: 0.7;
}

.alert__close:hover {
    opacity: 1;
}

/* Footer */
.footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: var(--spacing-lg) 0;
    margin-top: auto;
}

.footer__text {
    text-align: center;
    color: var(--text-muted);
    font-size: var(--font-size-sm);
}

/* Animations */
@keyframes slideIn {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

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

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

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    .header {
        padding: var(--spacing-lg) 0;
    }
    
    .header__title {
        font-size: var(--font-size-2xl);
    }
    
    .header__subtitle {
        font-size: var(--font-size-base);
    }
    
    .theme-toggle {
        width: 40px;
        height: 40px;
    }
    
    .budget-overview {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }
    
    .daily-expenses__header {
        flex-direction: column;
        align-items: stretch;
        text-align: center;
    }
    
    .expense-form__row {
        grid-template-columns: 1fr;
        gap: var(--spacing-sm);
    }
    
    .expense-item {
        flex-direction: column;
        align-items: stretch;
        gap: var(--spacing-sm);
    }
    
    .expense-item__info {
        order: 1;
    }
    
    .expense-item__amount {
        order: 2;
        text-align: center;
        margin-right: 0;
    }
    
    .expense-item__delete {
        order: 3;
        align-self: center;
    }
    
    .daily-summary {
        grid-template-columns: 1fr;
        gap: var(--spacing-sm);
    }
    
    .daily-summary__item {
        flex-direction: column;
        text-align: center;
        gap: var(--spacing-xs);
    }
    
    .actions {
        flex-direction: column;
    }
    
    .alert-container {
        left: var(--spacing-sm);
        right: var(--spacing-sm);
        max-width: none;
    }
    
    .day-selector {
        flex-wrap: wrap;
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .trip-form,
    .expense-form,
    .daily-expenses,
    .chart-section {
        padding: var(--spacing-md);
    }
    
    .budget-card {
        padding: var(--spacing-md);
    }
    
    .budget-card__value {
        font-size: var(--font-size-xl);
    }
    
    .section__title {
        font-size: var(--font-size-xl);
    }
}

/* Print Styles */
@media print {
    .theme-toggle,
    .actions,
    .alert-container {
        display: none !important;
    }
    
    .app {
        background: white !important;
        color: black !important;
    }
    
    .header {
        background: none !important;
        color: black !important;
    }
    
    .budget-card,
    .daily-expenses,
    .chart-section {
        box-shadow: none !important;
        border: 1px solid #ddd !important;
    }
}