:root {
    --primary: #4A90E2;
    --primary-dark: #3a7bc8;
    --secondary: #2E3A59;
    --accent: #FFA500;
    --danger: #E74C3C;
    --success: #2ECC71;
    --light: #F8F9FA;
    --dark: #212529;
    --gray: #6C757D;
    --light-gray: #E9ECEF;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: var(--light);
    color: var(--dark);
    line-height: 1.6;
}

header {
    background-color: white;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    padding: 1rem 2rem;
    position: sticky;
    top: 0;
    z-index: 100;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

header h1 {
    color: var(--primary);
    font-size: 1.8rem;
}

nav {
    display: flex;
    gap: 1rem;
}

.nav-btn {
    background: none;
    border: none;
    padding: 0.5rem 1rem;
    cursor: pointer;
    font-weight: 500;
    color: var(--gray);
    transition: all 0.3s ease;
    border-radius: 4px;
}

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

.nav-btn.active {
    color: var(--primary);
    background-color: rgba(74, 144, 226, 0.1);
}

main {
    padding: 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.section {
    display: none;
    animation: fadeIn 0.5s ease;
}

.section.active-section {
    display: block;
}

h2 {
    color: var(--secondary);
    margin-bottom: 1.5rem;
    font-size: 1.5rem;
}

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

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--secondary);
}

input, textarea, select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--light-gray);
    border-radius: 4px;
    font-size: 1rem;
    transition: border 0.3s ease;
}

input:focus, textarea:focus, select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(74, 144, 226, 0.2);
}

textarea {
    resize: vertical;
    min-height: 100px;
}

.submit-btn {
    background-color: var(--primary);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 4px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.submit-btn:hover {
    background-color: var(--primary-dark);
}

.pet-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
    margin-top: 1rem;
}

.pet-card {
    background-color: white;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.pet-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

.pet-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
}

.pet-details {
    padding: 1.5rem;
}

.pet-name {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--secondary);
}

.pet-breed, .pet-age {
    color: var(--gray);
    margin-bottom: 0.5rem;
}

.pet-actions {
    display: flex;
    gap: 0.5rem;
    margin-top: 1rem;
}

.action-btn {
    padding: 0.5rem 1rem;
    border-radius: 4px;
    font-size: 0.9rem;
    cursor: pointer;
    transition: all 0.3s ease;
    border: none;
}

.contact-btn {
    background-color: var(--primary);
    color: white;
}

.contact-btn:hover {
    background-color: var(--primary-dark);
}

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

.delete-btn:hover {
    background-color: #c0392b;
}

.empty-state {
    text-align: center;
    padding: 2rem;
    grid-column: 1 / -1;
    color: var(--gray);
}

.empty-state i {
    font-size: 3rem;
    margin-bottom: 1rem;
    color: var(--light-gray);
}

.image-preview {
    margin-top: 1rem;
    width: 100%;
    height: 200px;
    border: 1px dashed var(--light-gray);
    border-radius: 4px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.image-preview img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
}

.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
}

.modal.active {
    opacity: 1;
    pointer-events: all;
}

.modal-content {
    background-color: white;
    padding: 2rem;
    border-radius: 8px;
    max-width: 500px;
    width: 90%;
    box-shadow: 0 5px 20px rgba(0,0,0,0.2);
}

.modal h3 {
    margin-bottom: 1rem;
    color: var(--secondary);
}

.modal-actions {
    display: flex;
    gap: 1rem;
    margin-top: 1.5rem;
    justify-content: flex-end;
}

.secondary-btn {
    background-color: var(--light-gray);
    color: var(--dark);
}

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

.toast {
    position: fixed;
    bottom: 20px;
    right: 20px;
    padding: 1rem 1.5rem;
    border-radius: 4px;
    color: white;
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
    transform: translateY(100px);
    opacity: 0;
    transition: all 0.3s ease;
    z-index: 1000;
}

.toast.success {
    background-color: var(--success);
    transform: translateY(0);
    opacity: 1;
}

.toast.error {
    background-color: var(--danger);
    transform: translateY(0);
    opacity: 1;
}

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

@media (max-width: 768px) {
    header {
        flex-direction: column;
        gap: 1rem;
        padding: 1rem;
    }
    
    nav {
        width: 100%;
        justify-content: space-around;
    }
    
    .pet-list {
        grid-template-columns: 1fr;
    }
}
body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
}

header {
    background: #333;
    color: white;
    padding: 10px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

nav .nav-btn {
    padding: 10px 20px;
    margin: 0 5px;
    background: none;
    border: none;
    color: white;
    cursor: pointer;
}

nav .nav-btn.active {
    background: #555;
}

.section {
    display: none;
    padding: 20px;
}

.active-section {
    display: block;
}

form {
    max-width: 500px;
    margin: 0 auto;
}

.form-group {
    margin-bottom: 15px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
}

.form-group input, .form-group textarea {
    width: 100%;
    padding: 8px;
    box-sizing: border-box;
}

.submit-btn {
    background: #28a745;
    color: white;
    padding: 10px 20px;
    border: none;
    cursor: pointer;
}

.pet-list {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
}

.pet-card {
    border: 1px solid #ddd;
    padding: 15px;
    width: 300px;
    position: relative;
}

.pet-image {
    margin-bottom: 10px;
}

.delete-btn {
    background: #dc3545;
    color: white;
    padding: 5px 10px;
    border: none;
    cursor: pointer;
    margin-top: 10px;
}

.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
}

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

.modal-content {
    background: white;
    padding: 20px;
    border-radius: 5px;
    text-align: center;
}

.modal-actions button {
    margin: 0 10px;
    padding: 8px 16px;
}

.danger-btn {
    background: #dc3545;
    color: white;
    border: none;
}

.secondary-btn {
    background: #6c757d;
    color: white;
    border: none;
}

.toast {
    position: fixed;
    bottom: 20px;
    right: 20px;
    padding: 10px 20px;
    background: #28a745;
    color: white;
    border-radius: 5px;
}

.toast.error {
    background: #dc3545;
}

.hidden {
    display: none;
}