* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: #333;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
}

header {
    text-align: center;
    margin-bottom: 30px;
}

header h1 {
    color: white;
    font-size: 2.5rem;
    font-weight: 700;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
}

.input-section {
    background: white;
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
    margin-bottom: 30px;
}

.form-group {
    margin-bottom: 20px;
}

label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: #555;
}

input[type="text"],
input[type="number"] {
    width: 100%;
    padding: 15px;
    border: 2px solid #e1e5e9;
    border-radius: 10px;
    font-size: 16px;
    transition: border-color 0.3s ease;
}

input[type="text"]:focus,
input[type="number"]:focus {
    outline: none;
    border-color: #2196F3;
}

.btn-primary {
    width: 100%;
    padding: 15px;
    background: linear-gradient(135deg, #2196F3, #21CBF3);
    color: white;
    border: none;
    border-radius: 10px;
    font-size: 18px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s ease;
}

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

.btn-secondary {
    padding: 10px 20px;
    background: #4CAF50;
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 14px;
    cursor: pointer;
    transition: background 0.3s ease;
}

.btn-secondary:hover {
    background: #45a049;
}

.btn-danger {
    padding: 5px 10px;
    background: #f44336;
    color: white;
    border: none;
    border-radius: 5px;
    font-size: 12px;
    cursor: pointer;
    margin-left: 10px;
}

.btn-danger:hover {
    background: #da190b;
}

.categories-section {
    background: white;
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
}

.categories-section h2 {
    margin-bottom: 20px;
    color: #333;
    text-align: center;
}

.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 15px;
}

.category-card {
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    padding: 20px;
    border-radius: 12px;
    text-align: center;
    cursor: pointer;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    color: white;
}

.category-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 35px rgba(0,0,0,0.3);
}

.category-name {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 10px;
}

.category-amount {
    font-size: 24px;
    font-weight: 700;
}

/* Modal Styles */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
    animation: fadeIn 0.3s ease;
}

.modal-content {
    background-color: white;
    margin: 5% auto;
    padding: 0;
    border-radius: 15px;
    width: 90%;
    max-width: 500px;
    max-height: 80vh;
    overflow-y: auto;
    animation: slideIn 0.3s ease;
}

.modal-header {
    padding: 20px 30px;
    border-bottom: 1px solid #eee;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h3 {
    margin: 0;
    color: #333;
}

.close {
    color: #aaa;
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
    line-height: 1;
}

.close:hover {
    color: #000;
}

.modal-body {
    padding: 30px;
}

.category-options {
    display: grid;
    gap: 10px;
    margin-bottom: 20px;
}

.category-option {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px;
    background: #f8f9fa;
    border-radius: 10px;
    cursor: pointer;
    transition: background 0.3s ease;
}

.category-option:hover {
    background: #e9ecef;
}

.add-category-section {
    display: flex;
    gap: 10px;
    margin-top: 20px;
}

.add-category-section input {
    flex: 1;
    padding: 10px;
    border: 2px solid #e1e5e9;
    border-radius: 8px;
}

.expense-list {
    display: grid;
    gap: 10px;
}

.expense-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px;
    background: #f8f9fa;
    border-radius: 10px;
}

.expense-description {
    font-weight: 600;
    color: #333;
}

.expense-amount {
    font-weight: 700;
    color: #2196F3;
    font-size: 18px;
}

.expense-date {
    font-size: 12px;
    color: #666;
    margin-top: 5px;
}

.empty-state {
    text-align: center;
    padding: 40px;
    color: #666;
}

.empty-state-icon {
    font-size: 48px;
    margin-bottom: 20px;
}

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

@keyframes slideIn {
    from { transform: translateY(-50px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    header h1 {
        font-size: 2rem;
    }
    
    .input-section,
    .categories-section {
        padding: 20px;
    }
    
    .categories-grid {
        grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
        gap: 10px;
    }
    
    .modal-content {
        width: 95%;
        margin: 10% auto;
    }
    
    .add-category-section {
        flex-direction: column;
    }
}