/* CSS Variables */
:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #64748b;
    --secondary-hover: #475569;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --danger-hover: #dc2626;
    --background: #f3f4f6;
    --panel-bg: #ffffff;
    --border-color: #e5e7eb;
    --text-primary: #111827;
    --text-secondary: #4b5563;
    --text-muted: #9ca3af;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
}

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

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--border-color);
}

header h1 {
    font-size: 2.25rem;
    font-weight: 800;
    color: #1e3a8a;
}

.header-actions {
    display: flex;
    gap: 8px;
}

main {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

/* Panels */
.panel {
    background: var(--panel-bg);
    border-radius: 12px;
    padding: 24px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    border: 1px solid var(--border-color);
}

.panel h2 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 16px;
    margin-bottom: 16px;
}

.section-header h2 {
    margin-bottom: 4px;
}

.section-header .help-text {
    margin-bottom: 0;
}

.section-actions {
    display: flex;
    gap: 8px;
    flex-shrink: 0;
}

.subsection {
    margin-top: 24px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
}

.subsection h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.help-text {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-bottom: 12px;
}

/* Forms */
.form-group {
    margin-bottom: 16px;
}

.form-group label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: 6px;
    color: var(--text-secondary);
}

.form-row {
    display: flex;
    gap: 16px;
}

.form-row .form-group {
    flex: 1;
}

input[type="text"],
input[type="date"],
select {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 0.9375rem;
    transition: border-color 0.2s, box-shadow 0.2s;
}

input[type="text"]:focus,
input[type="date"]:focus,
select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.inline-form {
    display: flex;
    gap: 8px;
    margin-top: 12px;
}

.inline-form input {
    flex: 1;
    max-width: 200px;
}

/* Buttons */
.btn {
    padding: 10px 16px;
    border: none;
    border-radius: 6px;
    font-size: 0.9375rem;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s;
}

.btn:hover {
    transform: translateY(-1px);
}

.btn:active {
    transform: translateY(0);
}

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

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

.btn-secondary {
    background: white;
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background: #f9fafb;
    border-color: #d1d5db;
}

.btn-add {
    background: transparent;
    color: var(--primary-color);
    border: 2px dashed var(--primary-color);
    width: 100%;
    margin-top: 12px;
}

.btn-add:hover {
    background: rgba(37, 99, 235, 0.05);
}

.btn-small {
    padding: 8px 12px;
    font-size: 0.875rem;
}

.btn-icon {
    padding: 6px 10px;
    background: transparent;
    color: var(--text-secondary);
}

.btn-icon:hover {
    background: var(--background);
    color: var(--text-primary);
}

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

/* CLLO List */
.item-list {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.cllo-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px;
    background: var(--background);
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.cllo-number {
    font-weight: 600;
    color: var(--primary-color);
    min-width: 60px;
}

.cllo-description {
    flex: 1;
    padding: 8px;
    border: 1px solid transparent;
    border-radius: 4px;
    background: transparent;
    font-size: 0.9375rem;
}

.cllo-description:focus {
    border-color: var(--border-color);
    background: white;
    outline: none;
}

.cllo-actions {
    display: flex;
    gap: 4px;
}

/* Summary Table */
.summary-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 16px;
    font-size: 0.875rem;
}

.summary-table th,
.summary-table td {
    padding: 8px 12px;
    border: 1px solid var(--border-color);
    text-align: left;
}

.summary-table th {
    background: var(--background);
    font-weight: 600;
}

/* Assignment Type Tags */
.tag-list {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.tag {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 12px;
    background: var(--background);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    font-size: 0.875rem;
}

.tag .remove-tag {
    cursor: pointer;
    color: var(--text-muted);
    font-size: 1rem;
    line-height: 1;
}

.tag .remove-tag:hover {
    color: var(--danger-color);
}

/* Module List */
.module-list {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.module-item {
    background: var(--background);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    overflow: hidden;
}

.module-header {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px;
    background: white;
    border-bottom: 1px solid var(--border-color);
    cursor: grab;
}

.module-header:active {
    cursor: grabbing;
}

.collapse-toggle {
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
    font-size: 1rem;
    color: var(--text-secondary);
    transition: transform 0.2s;
    line-height: 1;
}

.collapse-toggle:hover {
    color: var(--text-primary);
}

.module-item.collapsed .collapse-toggle {
    transform: rotate(-90deg);
}

.module-item.collapsed .module-header {
    border-bottom: none;
}

.module-content {
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
    max-height: 1000px;
}

.module-item.collapsed .module-content {
    max-height: 0;
    padding-top: 0;
    padding-bottom: 0;
}

.drag-handle {
    color: var(--text-muted);
    font-size: 1.25rem;
}

.module-info {
    flex: 1;
}

.module-title {
    font-weight: 600;
    font-size: 1rem;
}

.module-dates {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.module-topic {
    font-size: 0.875rem;
    color: var(--text-muted);
    font-style: italic;
}

.assignment-count {
    font-size: 0.8125rem;
    color: var(--text-muted);
    margin-left: auto;
}

.module-actions {
    display: flex;
    gap: 4px;
}

.module-content {
    padding: 12px 16px;
}

.assignment-list {
    display: flex;
    flex-direction: column;
    gap: 8px;
    min-height: 40px;
}

.assignment-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 12px;
    background: white;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    cursor: grab;
}

.assignment-item:active {
    cursor: grabbing;
}

.assignment-item .drag-handle {
    font-size: 1rem;
}

.assignment-info {
    flex: 1;
}

.assignment-name {
    font-weight: 500;
}

.assignment-meta {
    font-size: 0.8125rem;
    color: var(--text-secondary);
}

.assignment-type {
    background: var(--primary-color);
    color: white;
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 0.75rem;
    margin-right: 8px;
}

    .assignment-points {
        background: var(--border-color);
        color: var(--text-secondary);
        padding: 2px 8px;
        border-radius: 4px;
        font-size: 0.75rem;
        margin-right: 8px;
    }

.assignment-cllos {
    color: var(--text-muted);
}

.assignment-due {
    font-size: 0.8125rem;
    color: var(--text-secondary);
    min-width: 80px;
    text-align: right;
}

.assignment-actions {
    display: flex;
    gap: 4px;
}

.btn-add-assignment {
    margin-top: 8px;
    padding: 8px 12px;
    background: transparent;
    border: 1px dashed var(--border-color);
    border-radius: 6px;
    color: var(--text-secondary);
    cursor: pointer;
    width: 100%;
    font-size: 0.875rem;
}

.btn-add-assignment:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    background: rgba(37, 99, 235, 0.05);
}

/* Preview Table */
.export-actions {
    display: flex;
    gap: 8px;
    margin-bottom: 16px;
}

.table-preview {
    overflow-x: auto;
}

.table-preview table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9375rem;
}

.table-preview th,
.table-preview td {
    padding: 12px;
    text-align: left;
    border: 1px solid var(--border-color);
}

.table-preview th {
    background: var(--background);
    font-weight: 600;
}

.table-preview tr:hover td {
    background: rgba(37, 99, 235, 0.02);
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.modal.hidden {
    display: none;
}

.modal-content {
    background: white;
    padding: 24px;
    border-radius: 12px;
    width: 90%;
    max-width: 500px;
    max-height: 90vh;
    overflow-y: auto;
}

.modal-content h3 {
    margin-bottom: 20px;
    font-size: 1.25rem;
}

.modal-actions {
    display: flex;
    justify-content: flex-end;
    gap: 8px;
    margin-top: 24px;
}

/* Checkbox Group */
.checkbox-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.checkbox-item {
    display: flex;
    align-items: flex-start;
    gap: 8px;
}

.checkbox-item input[type="checkbox"] {
    margin-top: 4px;
}

.checkbox-item label {
    font-size: 0.9375rem;
    cursor: pointer;
}

/* Sortable Ghost */
.sortable-ghost {
    opacity: 0.4;
}

.sortable-chosen {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 24px;
    color: var(--text-muted);
    font-style: italic;
}

/* Toast Notification */
.toast {
    position: fixed;
    bottom: 24px;
    right: 24px;
    background: var(--text-primary);
    color: white;
    padding: 12px 20px;
    border-radius: 8px;
    font-size: 0.9375rem;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    z-index: 2000;
    animation: slideIn 0.3s ease;
}

.toast.success {
    background: var(--success-color);
}

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

/* Footer */
.app-footer {
    margin-top: 40px;
    padding: 24px;
    text-align: center;
    border-top: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.app-footer a {
    color: var(--primary-color);
    text-decoration: none;
}

.app-footer a:hover {
    text-decoration: underline;
}

.footer-note {
    margin-top: 4px;
    color: var(--text-muted);
    font-size: 0.8125rem;
}

/* Responsive */
@media (max-width: 768px) {
    .container {
        padding: 12px;
    }

    header {
        flex-direction: column;
        gap: 12px;
        text-align: center;
    }

    .form-row {
        flex-direction: column;
    }

    .export-actions {
        flex-direction: column;
    }

    .export-actions .btn {
        width: 100%;
    }
}