:root {
    /* Color Palette */
    --bg-base: #1A100E;
    --bg-panel: rgba(43, 27, 24, 0.6);
    --bg-glass-border: rgba(255, 255, 255, 0.08);

    --primary: #E17055;
    --primary-hover: #fa8264;
    --secondary: #FAB1A0;
    --accent: #FFEAA7;

    --text-primary: #FFFFFF;
    --text-secondary: #B1A3A0;
    --text-muted: #7A6F6D;

    --success: #55E18D;
    --error: #E15555;
    --warning: #FFEAA7;

    /* Conflict Colors */
    --conflict-current-bg: rgba(85, 225, 141, 0.15);
    --conflict-current-border: #55E18D;

    --conflict-incoming-bg: rgba(225, 112, 85, 0.15);
    --conflict-incoming-border: #E17055;

    --conflict-marker-color: #B1A3A0;

    /* Theme Specs */
    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 16px;

    --shadow-glass: 0 8px 32px 0 rgba(0, 0, 0, 0.3);
    --shadow-glow: 0 0 15px rgba(225, 112, 85, 0.3);

    --font-ui: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    --font-code: 'Fira Code', source-code-pro, Menlo, Monaco, Consolas, "Courier New", monospace;
}

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

body {
    font-family: var(--font-ui);
    background-color: var(--bg-base);
    color: var(--text-primary);
    line-height: 1.6;
    height: 100vh;
    overflow: hidden;
    /* Subtle radial gradient background */
    background-image: radial-gradient(circle at top right, rgba(225, 112, 85, 0.1), transparent 40%),
        radial-gradient(circle at bottom left, rgba(250, 177, 160, 0.05), transparent 40%);
}

.app-container {
    display: flex;
    height: 100vh;
    padding: 1rem;
    gap: 1rem;
    max-width: 1600px;
    margin: 0 auto;
}

/* Glassmorphism Classes */
.glass-panel {
    background: var(--bg-panel);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--bg-glass-border);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-glass);
}

/* Typography */
h1,
h2,
h3 {
    font-weight: 600;
    color: var(--text-primary);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.6rem 1.2rem;
    border-radius: var(--radius-sm);
    font-family: var(--font-ui);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    border: none;
    outline: none;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.primary-btn {
    background-color: var(--primary);
    color: #fff;
    box-shadow: 0 4px 10px rgba(225, 112, 85, 0.2);
}

.primary-btn:not(:disabled):hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-glow);
}

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

.secondary-btn:not(:disabled):hover {
    color: var(--text-primary);
    border-color: var(--text-secondary);
    background-color: rgba(255, 255, 255, 0.05);
}

.icon-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 1.1rem;
    transition: color 0.2s;
}

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

/* ---> Sidebar <--- */
.sidebar {
    width: 320px;
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
    overflow: hidden;
}

.sidebar-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--bg-glass-border);
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: var(--primary);
}

.progress-section {
    padding: 1.5rem;
    border-bottom: 1px solid var(--bg-glass-border);
}

.progress-header {
    display: flex;
    justify-content: space-between;
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
}

.progress-bar {
    height: 6px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 3px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--secondary), var(--primary));
    border-radius: 3px;
    transition: width 0.4s ease;
}

.level-list {
    flex: 1;
    overflow-y: auto;
    padding: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.level-item {
    padding: 1rem;
    border-radius: var(--radius-sm);
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid transparent;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    gap: 1rem;
}

.level-item:hover {
    background: rgba(255, 255, 255, 0.06);
}

.level-item.active {
    background: rgba(225, 112, 85, 0.1);
    border-color: rgba(225, 112, 85, 0.3);
}

.level-item.completed .level-icon {
    color: var(--success);
}

.level-icon {
    color: var(--text-muted);
    font-size: 1.2rem;
    width: 24px;
    text-align: center;
}

.level-info h4 {
    font-size: 0.95rem;
    margin-bottom: 0.2rem;
}

.level-info p {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.sidebar-footer {
    padding: 1rem;
    border-top: 1px solid var(--bg-glass-border);
}

.sidebar-footer .btn {
    width: 100%;
    font-size: 0.8rem;
}

/* ---> Main Workspace <--- */
.workspace {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    min-width: 0;
}

/* Header */
.workspace-header {
    padding: 1.5rem;
}

.scenario-info {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 0.5rem;
}

.difficulty-badge {
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    padding: 0.2rem 0.6rem;
    border-radius: 12px;
    font-weight: 600;
}

.difficulty-badge.easy {
    background: rgba(85, 225, 141, 0.15);
    color: var(--success);
}

.difficulty-badge.medium {
    background: rgba(255, 234, 167, 0.15);
    color: var(--warning);
}

.difficulty-badge.hard {
    background: rgba(225, 85, 85, 0.15);
    color: var(--error);
}

.scenario-desc {
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin-bottom: 1.5rem;
}

/* Branch Timeline */
.branch-timeline {
    position: relative;
    height: 48px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding-left: 2rem;
}

.branch {
    position: absolute;
    display: flex;
    align-items: center;
    width: 100%;
    height: 2px;
    background: var(--text-muted);
}

.branch.master {
    top: 12px;
}

.branch.feature {
    top: 36px;
}

.branch-label {
    position: absolute;
    left: -2rem;
    top: -10px;
    font-family: var(--font-code);
    font-size: 0.7rem;
    color: var(--text-secondary);
    background: var(--bg-base);
    padding: 0 0.25rem;
}

.commit-dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    position: absolute;
    background: var(--bg-base);
    border: 2px solid;
}

.commit-dot.head {
    right: 20%;
    border-color: var(--success);
    box-shadow: 0 0 8px rgba(85, 225, 141, 0.4);
}

.commit-dot.new {
    right: 40%;
    border-color: var(--primary);
    box-shadow: 0 0 8px rgba(225, 112, 85, 0.4);
}

.merge-line {
    position: absolute;
    right: 20%;
    top: 12px;
    width: 20%;
    height: 24px;
    border-bottom: 2px dashed var(--primary);
    border-right: 2px dashed var(--primary);
    border-bottom-right-radius: 8px;
    opacity: 0.5;
}

/* Editor Section */
.editor-section {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 0;
    min-height: 0;
}

.file-tabs {
    border-bottom-left-radius: 0;
    border-bottom-right-radius: 0;
    border-bottom: none;
    padding: 0.5rem 1rem 0;
    display: flex;
    gap: 0.5rem;
}

.tab {
    padding: 0.5rem 1rem;
    background: rgba(255, 255, 255, 0.05);
    border-top-left-radius: var(--radius-sm);
    border-top-right-radius: var(--radius-sm);
    font-family: var(--font-code);
    font-size: 0.85rem;
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.tab.active {
    background: var(--bg-panel);
    color: var(--accent);
    border-top: 2px solid var(--primary);
}

.merge-editor {
    flex: 1;
    border-top-left-radius: 0;
    border-top-right-radius: 0;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    position: relative;
}

.editor-toolbar {
    padding: 0.75rem 1rem;
    background: rgba(0, 0, 0, 0.2);
    border-bottom: 1px solid var(--bg-glass-border);
    display: flex;
    justify-content: flex-end;
    /* Invisible until a conflict block header is clicked/active, but we keep it visible for UI layout */
    opacity: 0.5;
    pointer-events: none;
    transition: opacity 0.2s;
}

.editor-toolbar.active {
    opacity: 1;
    pointer-events: auto;
}

.toolbar-actions {
    display: flex;
    gap: 0.5rem;
}

.resolve-btn {
    font-size: 0.75rem;
    padding: 0.4rem 0.8rem;
    background: rgba(255, 255, 255, 0.1);
}

.resolve-btn[data-action="accept-current"]:hover {
    background: rgba(85, 225, 141, 0.3);
    color: #fff;
}

.resolve-btn[data-action="accept-incoming"]:hover {
    background: rgba(225, 112, 85, 0.3);
    color: #fff;
}

.resolve-btn[data-action="accept-both"]:hover {
    background: rgba(255, 234, 167, 0.3);
    color: #fff;
}

.code-container {
    flex: 1;
    overflow-y: auto;
    padding: 1rem 0;
    font-family: var(--font-code);
    font-size: 0.9rem;
    line-height: 1.5;
}

/* Code Line Styling */
.code-line {
    display: flex;
    padding: 0 1rem;
    position: relative;
    white-space: pre-wrap;
    word-break: break-all;
}

.line-num {
    width: 40px;
    flex-shrink: 0;
    color: var(--text-muted);
    text-align: right;
    padding-right: 1rem;
    user-select: none;
}

.line-content {
    flex: 1;
}

/* Conflict Blocks */
.conflict-block {
    margin: 0.25rem 0;
    cursor: pointer;
    border-left: 3px solid transparent;
    transition: border-color 0.2s;
}

.conflict-block.selected {
    border-left-color: var(--accent);
}

.conflict-header {
    font-family: var(--font-ui);
    font-size: 0.75rem;
    color: var(--text-muted);
    padding: 0.25rem 1rem 0.25rem 40px;
    background: rgba(255, 255, 255, 0.05);
    user-select: none;
}

.conflict-marker {
    color: var(--text-muted);
    font-weight: bold;
    background: rgba(255, 255, 255, 0.03);
}

.conflict-current {
    background-color: var(--conflict-current-bg);
    border-left: 2px solid var(--conflict-current-border);
}

.conflict-incoming {
    background-color: var(--conflict-incoming-bg);
    border-left: 2px solid var(--conflict-incoming-border);
}

/* Footer Action area */
.workspace-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.5rem;
}

.status-message {
    font-size: 0.9rem;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.status-message.success {
    color: var(--success);
}

/* Modals */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(4px);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
}

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

.modal-content {
    width: 100%;
    max-width: 600px;
    max-height: 90vh;
    display: flex;
    flex-direction: column;
}

.modal-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--bg-glass-border);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-body {
    padding: 1.5rem;
    overflow-y: auto;
    color: var(--text-secondary);
}

.conflict-anatomy {
    margin: 1.5rem 0;
    background: rgba(0, 0, 0, 0.3);
    border-radius: var(--radius-sm);
    padding: 1rem;
}

.conflict-anatomy h3 {
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.code-snippet {
    font-family: var(--font-code);
    font-size: 0.85rem;
    line-height: 1.4;
}

.code-snippet .marker {
    color: var(--text-muted);
    padding: 0.2rem;
}

.code-snippet .content.current {
    background: var(--conflict-current-bg);
    padding: 0.2rem;
    border-left: 2px solid var(--conflict-current-border);
}

.code-snippet .content.incoming {
    background: var(--conflict-incoming-bg);
    padding: 0.2rem;
    border-left: 2px solid var(--conflict-incoming-border);
}

.tutorial-steps {
    padding-left: 1.5rem;
    margin-top: 1rem;
}

.tutorial-steps li {
    margin-bottom: 0.5rem;
}

.tutorial-steps strong {
    color: var(--text-primary);
}

.modal-footer {
    padding: 1.5rem;
    border-top: 1px solid var(--bg-glass-border);
    display: flex;
    justify-content: flex-end;
}

/* Animations */
@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate-slide-in {
    animation: slideIn 0.3s ease forwards;
}

/* Utilities */
.code-added {
    background-color: rgba(85, 225, 141, 0.1);
}

/* Scrollbars */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: rgba(0, 0, 0, 0.2);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.2);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: rgba(255, 255, 255, 0.3);
}

/* Responsive */
@media (max-width: 900px) {
    .app-container {
        flex-direction: column;
    }

    .sidebar {
        width: 100%;
        height: 200px;
        flex-direction: row;
    }

    .level-list {
        flex-direction: row;
        overflow-x: auto;
        overflow-y: hidden;
    }

    .level-item {
        flex-direction: column;
        justify-content: center;
        text-align: center;
        min-width: 120px;
    }
}