:root {
    /* Color palette */
    --primary-color: #2c3e50;
    --secondary-color: #1a5276;
    --accent-color: #3498db;
    --light-color: #f8f9fa;
    --dark-color: #212529;
    --success-color: #27ae60;
    --error-color: #e74c3c;
    --warning-color: #f39c12;
    --text-color: #34495e;
    --border-color: #dfe6e9;
    --card-bg: #ffffff;
    --sidebar-bg: #f5f7fa;
    --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1), 0 1px 3px rgba(0,0,0,0.08);
    --shadow-lg: 0 10px 25px rgba(0,0,0,0.1), 0 5px 10px rgba(0,0,0,0.05);
    --shadow-xl: 0 20px 40px rgba(0,0,0,0.15), 0 10px 10px rgba(0,0,0,0.05);
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 14px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', 'Roboto', 'Helvetica Neue', sans-serif;
}

body {
    background-color: #f5f7fa;
    color: var(--text-color);
    min-height: 100vh;
    line-height: 1.6;
}

header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    box-shadow: var(--shadow-md);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: white;
    text-decoration: none;
    display: flex;
    align-items: center;
    transition: var(--transition);
}

.logo:hover {
    opacity: 0.9;
}

.logo i {
    margin-right: 0.8rem;
    color: var(--accent-color);
    font-size: 1.8rem;
}

.back-btn {
    display: flex;
    align-items: center;
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    padding: 0.6rem 1rem;
    border-radius: var(--radius-sm);
    background: rgba(255, 255, 255, 0.1);
    font-size: 0.95rem;
}

.back-btn:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-1px);
}

.back-btn i {
    margin-right: 0.5rem;
}

.main-container {
    display: flex;
    max-width: 1400px;
    margin: 2rem auto;
    padding: 0 2rem;
    gap: 2rem;
}

.form-sidebar {
    flex: 0 0 280px;
    background: var(--sidebar-bg);
    border-radius: var(--radius-md);
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
    height: fit-content;
    position: sticky;
    top: 100px;
}

.form-sidebar h3 {
    margin-bottom: 1.5rem;
    color: var(--primary-color);
    font-size: 1.2rem;
    font-weight: 600;
    position: relative;
    padding-bottom: 0.5rem;
}

.form-sidebar h3::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    width: 40px;
    height: 3px;
    background: var(--accent-color);
    border-radius: 3px;
}

.form-progress {
    list-style: none;
}

.form-progress li {
    margin-bottom: 1.5rem;
    position: relative;
    padding-left: 2rem;
    transition: var(--transition);
}

.form-progress li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0.2rem;
    width: 1.2rem;
    height: 1.2rem;
    border-radius: 50%;
    background: #bdc3c7;
    border: 3px solid var(--sidebar-bg);
    transition: var(--transition);
}

.form-progress li.active::before {
    background: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.2);
}

.form-progress li.completed::before {
    background: var(--success-color);
    box-shadow: 0 0 0 3px rgba(39, 174, 96, 0.2);
}

.form-progress li.completed::after {
    content: '\f00c';
    font-family: 'Font Awesome 6 Free';
    font-weight: 900;
    position: absolute;
    left: 0.3rem;
    top: 0.2rem;
    color: white;
    font-size: 0.7rem;
}

.form-progress li:not(:last-child)::after {
    content: '';
    position: absolute;
    left: 0.5rem;
    top: 1.4rem;
    bottom: -1.7rem;
    width: 2px;
    background: #bdc3c7;
}

.form-progress strong {
    display: block;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 0.3rem;
}

.form-progress p {
    font-size: 0.85rem;
    color: #7f8c8d;
}

.form-content {
    flex: 1;
    background: var(--card-bg);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    padding: 2rem;
    transition: var(--transition);
}

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

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

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.section-title {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
    position: relative;
    font-weight: 700;
}

.section-title::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: -1px;
    width: 60px;
    height: 3px;
    background: var(--accent-color);
    border-radius: 3px;
}

.section-description {
    color: #7f8c8d;
    margin-bottom: 1.5rem;
    font-size: 0.95rem;
}

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--primary-color);
    font-size: 0.95rem;
}

.form-control {
    width: 100%;
    padding: 0.9rem 1.2rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    font-size: 1rem;
    transition: var(--transition);
    background: white;
}

.form-control:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.2);
}

.form-select {
    appearance: none;
    background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
    background-repeat: no-repeat;
    background-position: right 1rem center;
    background-size: 1em;
}

.form-textarea {
    min-height: 150px;
    resize: vertical;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
}

.type-selector {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.2rem;
    margin-bottom: 2rem;
}

.type-option {
    position: relative;
}

.type-option input {
    position: absolute;
    opacity: 0;
}

.type-option label {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 1.8rem 1rem;
    background: white;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: var(--transition);
    text-align: center;
    height: 100%;
}

.type-option label i {
    font-size: 2.2rem;
    margin-bottom: 0.8rem;
    color: var(--accent-color);
}

.type-option label span {
    display: block;
}

.type-option label .type-description {
    font-size: 0.85rem;
    color: #7f8c8d;
    margin-top: 0.5rem;
}

.type-option input:checked + label {
    border-color: var(--accent-color);
    background: rgba(52, 152, 219, 0.05);
    box-shadow: var(--shadow-sm);
    transform: translateY(-3px);
}

.type-option input:focus + label {
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.3);
}

.selected-authors {
    margin-bottom: 1.5rem;
}

.search-container {
    position: relative;
    margin-bottom: 1.5rem;
}

.search-input {
    padding-left: 3rem;
}

.search-icon {
    position: absolute;
    left: 1.2rem;
    top: 50%;
    transform: translateY(-50%);
    color: #7f8c8d;
}

.authors-list-container {
    max-height: 300px;
    overflow-y: auto;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    margin-bottom: 1.5rem;
    background: white;
}

.authors-list {
    list-style: none;
}

.author-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
    transition: var(--transition);
}

.author-item:last-child {
    border-bottom: none;
}

.author-item:hover {
    background: #f8f9fa;
}

.author-info {
    flex: 1;
}

.author-name {
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 0.2rem;
}

.author-institution {
    font-size: 0.85rem;
    color: #7f8c8d;
}

.author-actions {
    display: flex;
    gap: 0.8rem;
}

.author-btn {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    border: none;
    cursor: pointer;
    transition: var(--transition);
    font-size: 1rem;
    color: white;
}

.add-author-btn {
    background: var(--success-color);
}

.add-author-btn:hover {
    background: #219653;
    transform: scale(1.1);
}

.remove-author-btn {
    background: var(--error-color);
}

.remove-author-btn:hover {
    background: #c0392b;
    transform: scale(1.1);
}

.selected-authors-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.8rem;
}

.selected-author {
    background: var(--accent-color);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 50px;
    font-size: 0.85rem;
    display: flex;
    align-items: center;
    gap: 0.8rem;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

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

.selected-author i {
    cursor: pointer;
    font-size: 0.8rem;
    opacity: 0.8;
    transition: var(--transition);
}

.selected-author i:hover {
    opacity: 1;
}

.new-author-form {
    display: none;
    padding: 1.5rem;
    background: #f8f9fa;
    border-radius: var(--radius-sm);
    margin-bottom: 1.5rem;
    border: 1px dashed var(--border-color);
    animation: fadeIn 0.4s ease;
}

.new-author-form.active {
    display: block;
}

.toggle-form-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.6rem;
    color: var(--accent-color);
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
    margin-bottom: 1.5rem;
    padding: 0.6rem 1rem;
    border-radius: var(--radius-sm);
    transition: var(--transition);
}

.toggle-form-btn:hover {
    background: rgba(52, 152, 219, 0.1);
}

.toggle-form-btn i {
    transition: var(--transition);
}

.toggle-form-btn.active i {
    transform: rotate(180deg);
}

.form-navigation {
    display: flex;
    justify-content: space-between;
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
}

.btn {
    padding: 0.9rem 2rem;
    border-radius: var(--radius-sm);
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    font-size: 1rem;
    border: none;
    display: inline-flex;
    align-items: center;
    gap: 0.6rem;
}

.btn-primary {
    background: var(--accent-color);
    color: white;
    box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
    background: #2980b9;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: #ecf0f1;
    color: var(--text-color);
}

.btn-secondary:hover {
    background: #dfe6e9;
    transform: translateY(-2px);
}

.btn-outline {
    background: transparent;
    border: 1px solid var(--accent-color);
    color: var(--accent-color);
}

.btn-outline:hover {
    background: rgba(52, 152, 219, 0.1);
}

.alert {
    padding: 1rem;
    border-radius: var(--radius-sm);
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 1rem;
    animation: slideDown 0.5s ease;
    border-left: 4px solid transparent;
}

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

.alert-success {
    background: rgba(39, 174, 96, 0.1);
    color: var(--success-color);
    border-left-color: var(--success-color);
}

.alert-error {
    background: rgba(231, 76, 60, 0.1);
    color: var(--error-color);
    border-left-color: var(--error-color);
}

.alert-warning {
    background: rgba(243, 156, 18, 0.1);
    color: var(--warning-color);
    border-left-color: var(--warning-color);
}

.alert i {
    font-size: 1.3rem;
}

.loading-item {
    text-align: center;
    padding: 2rem;
    color: #7f8c8d;
}

.loading-item i {
    margin-right: 0.5rem;
}

@media (max-width: 992px) {
    .main-container {
        flex-direction: column;
    }

    .form-sidebar {
        flex: 1;
        position: static;
        margin-bottom: 2rem;
    }
}

@media (max-width: 768px) {
    .main-container {
        padding: 0 1.5rem;
    }

    .header-content, .form-content {
        padding: 1.5rem;
    }

    .type-selector {
        grid-template-columns: 1fr 1fr;
    }

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

@media (max-width: 576px) {
    .type-selector {
        grid-template-columns: 1fr;
    }

    .form-navigation {
        flex-direction: column-reverse;
        gap: 1rem;
    }

    .btn {
        width: 100%;
        justify-content: center;
    }

    .header-content {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }

    .logo {
        justify-content: center;
    }
}