:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #64748b;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --background: #f8fafc;
    --card-background: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.navbar {
    background: var(--card-background);
    box-shadow: var(--shadow);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.navbar-brand {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
}

.nav-menu {
    display: flex;
    gap: 1.5rem;
    align-items: center;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

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

.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-block;
}

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

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

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

.btn-secondary:hover {
    background: #475569;
}

.btn-full {
    width: 100%;
}

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.btn-link {
    background: transparent;
    color: var(--text-secondary);
    padding: 0;
    border: none;
}

.card {
    background: var(--card-background);
    border-radius: 12px;
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: var(--shadow);
}

.card-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.page-title {
    font-size: 2rem;
    font-weight: 700;
    margin: 2rem 0;
    color: var(--text-primary);
}

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

.form-label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

.form-input,
.form-select {
    width: 100%;
    padding: 0.75rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.form-input:focus,
.form-select:focus {
    outline: none;
    border-color: var(--primary-color);
}

.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1rem;
}

.text-danger {
    color: var(--danger-color);
    font-size: 0.875rem;
    margin-top: 0.25rem;
    display: block;
}

.auth-page {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.auth-container {
    width: 100%;
    max-width: 450px;
    padding: 20px;
}

.auth-card {
    background: var(--card-background);
    border-radius: 16px;
    padding: 3rem;
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

.auth-title {
    font-size: 2rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.auth-subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

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

.auth-footer {
    text-align: center;
    color: var(--text-secondary);
}

.auth-link {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
}

.auth-link:hover {
    text-decoration: underline;
}

.image-preview {
    margin-top: 1rem;
}

.image-preview img {
    max-width: 300px;
    max-height: 200px;
    border-radius: 8px;
    box-shadow: var(--shadow);
}

.tags-preview {
    margin-top: 2rem;
}

.tags-preview-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

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

.tag-card {
    background: var(--card-background);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    transition: all 0.3s ease;
}

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

.tag-card h3 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.tag-card p {
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.barcode-container {
    margin: 1rem 0;
    text-align: center;
}

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

.return-card {
    background: var(--card-background);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    overflow: hidden;
    transition: all 0.3s ease;
}

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

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

.return-image-placeholder {
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--background);
    color: var(--text-secondary);
    font-weight: 600;
}

.return-details {
    padding: 1.5rem;
}

.return-details h3 {
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.return-details p {
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.summary-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.summary-card {
    background: var(--card-background);
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: var(--shadow);
    text-align: center;
}

.summary-card h3 {
    
    font-size: 1rem;
    margin-bottom: 0.5rem;
}

.summary-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
}

.returns-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.toast {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    background: var(--card-background);
    padding: 1rem 1.5rem;
    border-radius: 8px;
    box-shadow: var(--shadow-lg);
    transform: translateY(100px);
    opacity: 0;
    transition: all 0.3s ease;
    z-index: 2000;
}

.toast.show {
    transform: translateY(0);
    opacity: 1;
}

.toast.success {
    border-left: 4px solid var(--success-color);
}

.toast.error {
    border-left: 4px solid var(--danger-color);
}

.footer {
    background: var(--card-background);
    padding: 2rem 0;
    text-align: center;
    color: var(--text-secondary);
    margin-top: 4rem;
}

.loading {
    opacity: 0.6;
    pointer-events: none;
}

@media (max-width: 768px) {
    .nav-menu {
        flex-direction: column;
        gap: 0.5rem;
    }

    .page-title {
        font-size: 1.5rem;
    }

    .form-row {
        grid-template-columns: 1fr;
    }

    .tags-list,
    .returns-grid {
        grid-template-columns: 1fr;
    }

    .returns-header {
        flex-direction: column;
        gap: 1rem;
    }
}