Gemini 3.8 Flash
by GoogleReasoningClean
Running live in a sandboxed frame. Click inside it before using the keyboard.
How it went
- Total time
- 57.6 s
- Cost
- $0.040
- Output tokens
- 10,583
- Spent thinking
- 1,532 tokens
- Speed
- 193.5 tok/s
- Console errors
- 0
- First token after
- 2.9 s
- First visible text after
- 13.7 s
- Prompt tokens
- 507
- Code size
- 26.3 KB
- Finish reason
- stop
- Served by
- Model id
google/gemini-3.8-flash- Reasoning sent
{"effort":"medium"}- Max output
- 65,536 tokens
- Generated
- Nov 12, 2026
What it was asked
The prompt
Build an interactive Kanban board in vanilla HTML, CSS and JavaScript (no framework, no library). Requirements: - Three columns: "To do", "In progress", "Done", each showing its card count. - Pre-populate the board with 6 realistic cards spread across the columns so the first screenshot looks alive. - Each card has a title and a priority (low / medium / high) shown as a colored badge. - Add a card through a small modal form (title required), and delete a card with a button on it. - Drag and drop cards between columns with the mouse, with a clear visual drop indicator. - A search field that filters cards live by title. - A light / dark theme toggle. - State lives in memory only (no storage APIs).
System prompt, sent with every prompt
You are generating a self-contained web demo. It will be rendered automatically in a sandboxed iframe and compared side by side with the output of other AI models given the exact same task. Output rules: - Reply with exactly ONE fenced code block containing the complete file: ```html (or ```svg when the task asks for an SVG). No text before or after the code block. - Everything must be inline: CSS in <style>, JavaScript in <script>. No external files, images, fonts or network requests, except the CDN URLs explicitly allowed by the task. - Do not use localStorage, sessionStorage, cookies, IndexedDB, alert(), confirm(), prompt() or window.open(): they are blocked in the sandbox and will throw. - The page must look right in a 1280×800 viewport and adapt gracefully down to 375px wide. No horizontal scrollbar. - Something meaningful must be visible on first paint: a screenshot is taken automatically about 3 seconds after load, without any interaction. - Everything that makes the demo interesting must be visible within the first seconds: nothing hidden behind a high score, a later level or a long play session. - Games must start in a self-playing demo mode (a simple AI plays) behind a "Click or press a key to start" message, so the game can be judged in action without playing. - The iframe only receives keyboard events after the user clicks it: if the demo uses the keyboard, display a clear "Click or press a key to start" message. - The code must run with zero errors in the console of the latest Chrome.
Code run-1.html · 981 lines
<!DOCTYPE html>
<html lang="en" data-theme="light">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Kanban Studio</title>
<style>
:root {
--bg: #f1f5f9;
--surface: #ffffff;
--surface-subtle: #f8fafc;
--column-bg: #e2e8f0;
--border: #cbd5e1;
--border-subtle: #e2e8f0;
--text-main: #0f172a;
--text-muted: #64748b;
--text-inverse: #ffffff;
--accent: #3b82f6;
--accent-hover: #2563eb;
--shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.06);
--shadow-md: 0 4px 6px -1px rgba(15, 23, 42, 0.08), 0 2px 4px -2px rgba(15, 23, 42, 0.06);
--shadow-lg: 0 10px 15px -3px rgba(15, 23, 42, 0.1), 0 4px 6px -4px rgba(15, 23, 42, 0.08);
--p-low-bg: #ecfdf5;
--p-low-text: #047857;
--p-low-border: #a7f3d0;
--p-med-bg: #fffbeb;
--p-med-text: #b45309;
--p-med-border: #fde68a;
--p-high-bg: #fef2f2;
--p-high-text: #b91c1c;
--p-high-border: #fecaca;
--drop-indicator: #3b82f6;
}
[data-theme="dark"] {
--bg: #090d16;
--surface: #131b2e;
--surface-subtle: #1a243c;
--column-bg: #0f172a;
--border: #24304f;
--border-subtle: #1e293b;
--text-main: #f8fafc;
--text-muted: #94a3b8;
--text-inverse: #0f172a;
--accent: #3b82f6;
--accent-hover: #60a5fa;
--shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.4);
--shadow-md: 0 4px 8px -1px rgba(0, 0, 0, 0.5);
--shadow-lg: 0 12px 20px -3px rgba(0, 0, 0, 0.6);
--p-low-bg: rgba(16, 185, 129, 0.15);
--p-low-text: #34d399;
--p-low-border: rgba(16, 185, 129, 0.3);
--p-med-bg: rgba(245, 158, 11, 0.15);
--p-med-text: #fbbf24;
--p-med-border: rgba(245, 158, 11, 0.3);
--p-high-bg: rgba(239, 68, 68, 0.15);
--p-high-text: #f87171;
--p-high-border: rgba(239, 68, 68, 0.3);
--drop-indicator: #60a5fa;
}
* {
box-sizing: border-box;
margin: 0;
padding: 0;
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
transition: background-color 0.2s ease, border-color 0.2s ease, color 0.15s ease;
}
body {
background-color: var(--bg);
color: var(--text-main);
min-height: 100vh;
display: flex;
flex-direction: column;
overflow-x: hidden;
}
/* Top Navigation Bar */
header {
background-color: var(--surface);
border-bottom: 1px solid var(--border-subtle);
padding: 12px 24px;
display: flex;
align-items: center;
justify-content: space-between;
gap: 16px;
flex-wrap: wrap;
box-shadow: var(--shadow-sm);
z-index: 10;
}
.brand {
display: flex;
align-items: center;
gap: 10px;
}
.brand-logo {
width: 30px;
height: 30px;
background: linear-gradient(135deg, #3b82f6, #1d4ed8);
border-radius: 8px;
display: flex;
align-items: center;
justify-content: center;
color: #fff;
font-weight: 800;
font-size: 16px;
box-shadow: 0 2px 4px rgba(37, 99, 235, 0.3);
}
.brand h1 {
font-size: 1.15rem;
font-weight: 700;
letter-spacing: -0.02em;
}
.toolbar {
display: flex;
align-items: center;
gap: 12px;
flex: 1;
max-width: 580px;
justify-content: flex-end;
}
.search-box {
position: relative;
flex: 1;
max-width: 320px;
}
.search-box svg {
position: absolute;
left: 10px;
top: 50%;
transform: translateY(-50%);
width: 15px;
height: 15px;
fill: none;
stroke: var(--text-muted);
stroke-width: 2;
pointer-events: none;
}
.search-box input {
width: 100%;
padding: 7px 12px 7px 32px;
border-radius: 8px;
border: 1px solid var(--border);
background-color: var(--surface-subtle);
color: var(--text-main);
font-size: 0.85rem;
outline: none;
}
.search-box input:focus {
border-color: var(--accent);
box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
background-color: var(--surface);
}
.btn {
display: inline-flex;
align-items: center;
gap: 6px;
padding: 7px 14px;
border-radius: 8px;
font-size: 0.85rem;
font-weight: 600;
cursor: pointer;
border: none;
outline: none;
white-space: nowrap;
}
.btn-primary {
background-color: var(--accent);
color: #ffffff;
box-shadow: 0 1px 3px rgba(37, 99, 235, 0.25);
}
.btn-primary:hover {
background-color: var(--accent-hover);
}
.btn-secondary {
background-color: var(--surface-subtle);
border: 1px solid var(--border);
color: var(--text-main);
}
.btn-secondary:hover {
background-color: var(--border-subtle);
}
.theme-btn {
padding: 7px;
border-radius: 8px;
background-color: var(--surface-subtle);
border: 1px solid var(--border);
color: var(--text-main);
cursor: pointer;
display: flex;
align-items: center;
justify-content: center;
width: 34px;
height: 34px;
}
.theme-btn:hover {
background-color: var(--border-subtle);
}
/* Main Board Layout */
main {
flex: 1;
padding: 24px;
display: flex;
gap: 20px;
align-items: flex-start;
overflow-x: auto;
}
.column {
flex: 1;
min-width: 290px;
max-width: 420px;
background-color: var(--column-bg);
border-radius: 12px;
display: flex;
flex-direction: column;
max-height: calc(100vh - 120px);
border: 1px solid var(--border-subtle);
}
.column-header {
padding: 14px 16px 10px;
display: flex;
align-items: center;
justify-content: space-between;
user-select: none;
}
.column-title-group {
display: flex;
align-items: center;
gap: 8px;
}
.status-dot {
width: 8px;
height: 8px;
border-radius: 50%;
}
.dot-todo { background-color: #64748b; }
.dot-inprogress { background-color: #3b82f6; }
.dot-done { background-color: #10b981; }
.column-header h2 {
font-size: 0.92rem;
font-weight: 700;
text-transform: uppercase;
letter-spacing: 0.04em;
color: var(--text-main);
}
.card-count {
font-size: 0.75rem;
font-weight: 700;
background-color: var(--surface);
color: var(--text-muted);
border-radius: 20px;
padding: 2px 8px;
border: 1px solid var(--border);
}
.card-list {
padding: 8px 12px 14px;
flex: 1;
overflow-y: auto;
display: flex;
flex-direction: column;
gap: 10px;
min-height: 120px;
position: relative;
}
/* Cards */
.card {
background-color: var(--surface);
border-radius: 10px;
padding: 12px 14px;
box-shadow: var(--shadow-sm);
border: 1px solid var(--border-subtle);
cursor: grab;
user-select: none;
display: flex;
flex-direction: column;
gap: 10px;
position: relative;
}
.card:hover {
box-shadow: var(--shadow-md);
border-color: var(--border);
transform: translateY(-1px);
}
.card.dragging {
opacity: 0.45;
transform: scale(0.98);
cursor: grabbing;
box-shadow: none;
}
.card.hidden-by-search {
display: none !important;
}
.card-top {
display: flex;
align-items: flex-start;
justify-content: space-between;
gap: 10px;
}
.card-title {
font-size: 0.88rem;
font-weight: 500;
line-height: 1.38;
color: var(--text-main);
word-break: break-word;
}
.delete-btn {
background: none;
border: none;
color: var(--text-muted);
cursor: pointer;
padding: 3px;
border-radius: 4px;
display: flex;
align-items: center;
justify-content: center;
opacity: 0.6;
flex-shrink: 0;
}
.delete-btn:hover {
opacity: 1;
background-color: var(--border-subtle);
color: #ef4444;
}
.card-footer {
display: flex;
align-items: center;
justify-content: space-between;
margin-top: 2px;
}
.badge {
font-size: 0.72rem;
font-weight: 600;
padding: 2px 7px;
border-radius: 5px;
text-transform: capitalize;
letter-spacing: 0.02em;
border: 1px solid transparent;
}
.priority-low {
background-color: var(--p-low-bg);
color: var(--p-low-text);
border-color: var(--p-low-border);
}
.priority-medium {
background-color: var(--p-med-bg);
color: var(--p-med-text);
border-color: var(--p-med-border);
}
.priority-high {
background-color: var(--p-high-bg);
color: var(--p-high-text);
border-color: var(--p-high-border);
}
/* Drop Indicator Bar */
.drop-indicator {
height: 3px;
background: var(--drop-indicator);
border-radius: 2px;
margin: -3px 0;
box-shadow: 0 0 8px rgba(59, 130, 246, 0.6);
pointer-events: none;
}
/* Modal Form */
.modal-backdrop {
position: fixed;
inset: 0;
background-color: rgba(15, 23, 42, 0.55);
backdrop-filter: blur(2px);
display: flex;
align-items: center;
justify-content: center;
padding: 16px;
z-index: 100;
opacity: 0;
pointer-events: none;
transition: opacity 0.2s ease;
}
.modal-backdrop.open {
opacity: 1;
pointer-events: auto;
}
.modal {
background-color: var(--surface);
border-radius: 12px;
width: 100%;
max-width: 440px;
box-shadow: var(--shadow-lg);
border: 1px solid var(--border);
overflow: hidden;
transform: translateY(12px) scale(0.98);
transition: transform 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}
.modal-backdrop.open .modal {
transform: translateY(0) scale(1);
}
.modal-header {
padding: 16px 20px;
border-bottom: 1px solid var(--border-subtle);
display: flex;
justify-content: space-between;
align-items: center;
}
.modal-header h3 {
font-size: 1.05rem;
font-weight: 700;
}
.close-btn {
background: none;
border: none;
font-size: 1.3rem;
line-height: 1;
color: var(--text-muted);
cursor: pointer;
}
.close-btn:hover {
color: var(--text-main);
}
.modal-body {
padding: 20px;
display: flex;
flex-direction: column;
gap: 16px;
}
.form-group {
display: flex;
flex-direction: column;
gap: 6px;
}
.form-group label {
font-size: 0.8rem;
font-weight: 600;
color: var(--text-muted);
text-transform: uppercase;
letter-spacing: 0.03em;
}
.form-group input,
.form-group select {
padding: 9px 12px;
border-radius: 8px;
border: 1px solid var(--border);
background-color: var(--surface-subtle);
color: var(--text-main);
font-size: 0.9rem;
outline: none;
}
.form-group input:focus,
.form-group select:focus {
border-color: var(--accent);
background-color: var(--surface);
box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}
.modal-footer {
padding: 14px 20px;
background-color: var(--surface-subtle);
border-top: 1px solid var(--border-subtle);
display: flex;
justify-content: flex-end;
gap: 10px;
}
/* Empty state */
.empty-message {
padding: 28px 12px;
text-align: center;
font-size: 0.82rem;
color: var(--text-muted);
border: 1px dashed var(--border);
border-radius: 8px;
user-select: none;
}
@media (max-width: 820px) {
main {
flex-direction: column;
align-items: stretch;
}
.column {
max-width: 100%;
max-height: none;
}
.toolbar {
width: 100%;
max-width: 100%;
justify-content: space-between;
}
.search-box {
max-width: 100%;
}
}
</style>
</head>
<body>
<header>
<div class="brand">
<div class="brand-logo">K</div>
<h1>Sprint Board</h1>
</div>
<div class="toolbar">
<div class="search-box">
<svg viewBox="0 0 24 24"><circle cx="11" cy="11" r="8"></circle><line x1="21" y1="21" x2="16.65" y2="16.65"></line></svg>
<input type="text" id="searchInput" placeholder="Filter tasks by title..." autocomplete="off">
</div>
<button class="btn btn-primary" id="openModalBtn">
<svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.5"><line x1="12" y1="5" x2="12" y2="19"></line><line x1="5" y1="12" x2="19" y2="12"></line></svg>
<span>Add Task</span>
</button>
<button class="theme-btn" id="themeToggleBtn" aria-label="Toggle light/dark theme">
<svg id="themeIcon" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
<!-- Moon icon for light mode -->
<path d="M21 12.79A9 9 0 1 1 11.21 3 7 7 0 0 0 21 12.79z"></path>
</svg>
</button>
</div>
</header>
<main id="board">
<!-- To do Column -->
<div class="column" data-col-id="todo">
<div class="column-header">
<div class="column-title-group">
<span class="status-dot dot-todo"></span>
<h2>To Do</h2>
</div>
<span class="card-count" id="count-todo">0</span>
</div>
<div class="card-list" id="list-todo"></div>
</div>
<!-- In progress Column -->
<div class="column" data-col-id="inprogress">
<div class="column-header">
<div class="column-title-group">
<span class="status-dot dot-inprogress"></span>
<h2>In Progress</h2>
</div>
<span class="card-count" id="count-inprogress">0</span>
</div>
<div class="card-list" id="list-inprogress"></div>
</div>
<!-- Done Column -->
<div class="column" data-col-id="done">
<div class="column-header">
<div class="column-title-group">
<span class="status-dot dot-done"></span>
<h2>Done</h2>
</div>
<span class="card-count" id="count-done">0</span>
</div>
<div class="card-list" id="list-done"></div>
</div>
</main>
<!-- Add Card Modal -->
<div class="modal-backdrop" id="modalBackdrop">
<div class="modal">
<div class="modal-header">
<h3>Create New Task</h3>
<button class="close-btn" id="closeModalBtn">×</button>
</div>
<form id="addCardForm">
<div class="modal-body">
<div class="form-group">
<label for="taskTitle">Task Title *</label>
<input type="text" id="taskTitle" placeholder="e.g. Audit accessibility compliance" required maxlength="120" autocomplete="off">
</div>
<div class="form-group">
<label for="taskPriority">Priority</label>
<select id="taskPriority">
<option value="low">Low Priority</option>
<option value="medium" selected>Medium Priority</option>
<option value="high">High Priority</option>
</select>
</div>
<div class="form-group">
<label for="taskColumn">Target Column</label>
<select id="taskColumn">
<option value="todo">To Do</option>
<option value="inprogress">In Progress</option>
<option value="done">Done</option>
</select>
</div>
</div>
<div class="modal-footer">
<button type="button" class="btn btn-secondary" id="cancelModalBtn">Cancel</button>
<button type="submit" class="btn btn-primary">Create Task</button>
</div>
</form>
</div>
</div>
<script>
// State lives entirely in memory
const state = {
theme: 'light',
filterQuery: '',
cards: [
{
id: 'card-1',
title: 'Implement OAuth2 with Google & GitHub providers',
priority: 'high',
column: 'todo'
},
{
id: 'card-2',
title: 'Design zero-data dashboard illustrations',
priority: 'low',
column: 'todo'
},
{
id: 'card-3',
title: 'Refactor Redis caching layer for API gateway',
priority: 'high',
column: 'inprogress'
},
{
id: 'card-4',
title: 'Optimize JS bundle chunking & tree-shaking',
priority: 'medium',
column: 'inprogress'
},
{
id: 'card-5',
title: 'Set up automated CI/CD with GitHub Actions',
priority: 'medium',
column: 'done'
},
{
id: 'card-6',
title: 'Generate semantic design tokens for light & dark palettes',
priority: 'low',
column: 'done'
}
]
};
// DOM Elements
const root = document.documentElement;
const searchInput = document.getElementById('searchInput');
const themeToggleBtn = document.getElementById('themeToggleBtn');
const themeIcon = document.getElementById('themeIcon');
const modalBackdrop = document.getElementById('modalBackdrop');
const openModalBtn = document.getElementById('openModalBtn');
const closeModalBtn = document.getElementById('closeModalBtn');
const cancelModalBtn = document.getElementById('cancelModalBtn');
const addCardForm = document.getElementById('addCardForm');
const taskTitleInput = document.getElementById('taskTitle');
const taskPrioritySelect = document.getElementById('taskPriority');
const taskColumnSelect = document.getElementById('taskColumn');
const columnLists = {
todo: document.getElementById('list-todo'),
inprogress: document.getElementById('list-inprogress'),
done: document.getElementById('list-done')
};
const countBadges = {
todo: document.getElementById('count-todo'),
inprogress: document.getElementById('count-inprogress'),
done: document.getElementById('count-done')
};
// Drag-and-drop indicator tracking
let draggedCardId = null;
let dropIndicator = document.createElement('div');
dropIndicator.className = 'drop-indicator';
// Theme Toggle
themeToggleBtn.addEventListener('click', () => {
state.theme = state.theme === 'light' ? 'dark' : 'light';
root.setAttribute('data-theme', state.theme);
if (state.theme === 'dark') {
// Sun icon
themeIcon.innerHTML = `
<circle cx="12" cy="12" r="5"></circle>
<line x1="12" y1="1" x2="12" y2="3"></line>
<line x1="12" y1="21" x2="12" y2="23"></line>
<line x1="4.22" y1="4.22" x2="5.64" y2="5.64"></line>
<line x1="18.36" y1="18.36" x2="19.78" y2="19.78"></line>
<line x1="1" y1="12" x2="3" y2="12"></line>
<line x1="21" y1="12" x2="23" y2="12"></line>
<line x1="4.22" y1="19.78" x2="5.64" y2="18.36"></line>
<line x1="18.36" y1="5.64" x2="19.78" y2="4.22"></line>
`;
} else {
// Moon icon
themeIcon.innerHTML = `<path d="M21 12.79A9 9 0 1 1 11.21 3 7 7 0 0 0 21 12.79z"></path>`;
}
});
// Render Function
function renderBoard() {
const counts = { todo: 0, inprogress: 0, done: 0 };
const q = state.filterQuery.trim().toLowerCase();
// Clear lists
Object.values(columnLists).forEach(list => list.innerHTML = '');
// Populate cards
state.cards.forEach(card => {
const matchesSearch = !q || card.title.toLowerCase().includes(q);
if (matchesSearch) {
counts[card.column]++;
}
const cardEl = createCardElement(card, matchesSearch);
columnLists[card.column].appendChild(cardEl);
});
// Update Column Badges
Object.keys(counts).forEach(colId => {
countBadges[colId].textContent = counts[colId];
// Show subtle empty message if no matching visible cards
if (counts[colId] === 0) {
const empty = document.createElement('div');
empty.className = 'empty-message';
empty.textContent = q ? 'No matching cards' : 'No tasks yet';
columnLists[colId].appendChild(empty);
}
});
}
function createCardElement(card, isVisible) {
const el = document.createElement('div');
el.className = 'card';
if (!isVisible) el.classList.add('hidden-by-search');
el.draggable = true;
el.dataset.id = card.id;
el.innerHTML = `
<div class="card-top">
<span class="card-title">${escapeHTML(card.title)}</span>
<button class="delete-btn" aria-label="Delete card" title="Delete card">
<svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><polyline points="3 6 5 6 21 6"></polyline><path d="M19 6v14a2 2 0 0 1-2 2H7a2 2 0 0 1-2-2V6m3 0V4a2 2 0 0 1 2-2h4a2 2 0 0 1 2 2v2"></path></svg>
</button>
</div>
<div class="card-footer">
<span class="badge priority-${card.priority}">${card.priority}</span>
</div>
`;
// Drag event listeners on card
el.addEventListener('dragstart', (e) => {
draggedCardId = card.id;
el.classList.add('dragging');
e.dataTransfer.effectAllowed = 'move';
e.dataTransfer.setData('text/plain', card.id);
});
el.addEventListener('dragend', () => {
draggedCardId = null;
el.classList.remove('dragging');
if (dropIndicator.parentNode) {
dropIndicator.parentNode.removeChild(dropIndicator);
}
});
// Delete action
const deleteBtn = el.querySelector('.delete-btn');
deleteBtn.addEventListener('click', (e) => {
e.stopPropagation();
deleteCard(card.id);
});
return el;
}
function escapeHTML(str) {
return str.replace(/[&<>'"]/g,
tag => ({ '&': '&', '<': '<', '>': '>', "'": ''', '"': '"' }[tag] || tag)
);
}
function deleteCard(id) {
const idx = state.cards.findIndex(c => c.id === id);
if (idx !== -1) {
state.cards.splice(idx, 1);
renderBoard();
}
}
// Modal Control
function openModal() {
taskTitleInput.value = '';
taskPrioritySelect.value = 'medium';
modalBackdrop.classList.add('open');
taskTitleInput.focus();
}
function closeModal() {
modalBackdrop.classList.remove('open');
}
openModalBtn.addEventListener('click', openModal);
closeModalBtn.addEventListener('click', closeModal);
cancelModalBtn.addEventListener('click', closeModal);
modalBackdrop.addEventListener('click', (e) => {
if (e.target === modalBackdrop) closeModal();
});
document.addEventListener('keydown', (e) => {
if (e.key === 'Escape' && modalBackdrop.classList.contains('open')) {
closeModal();
}
});
addCardForm.addEventListener('submit', (e) => {
e.preventDefault();
const title = taskTitleInput.value.trim();
if (!title) return;
const newCard = {
id: 'card-' + Date.now(),
title: title,
priority: taskPrioritySelect.value,
column: taskColumnSelect.value
};
state.cards.push(newCard);
closeModal();
renderBoard();
});
// Search filter input
searchInput.addEventListener('input', (e) => {
state.filterQuery = e.target.value;
renderBoard();
});
// Drag and Drop Handling on Columns
Object.keys(columnLists).forEach(colId => {
const listEl = columnLists[colId];
listEl.addEventListener('dragover', (e) => {
e.preventDefault();
e.dataTransfer.dropEffect = 'move';
if (!draggedCardId) return;
const afterElement = getDragAfterElement(listEl, e.clientY);
if (afterElement == null) {
listEl.appendChild(dropIndicator);
} else {
listEl.insertBefore(dropIndicator, afterElement);
}
});
listEl.addEventListener('dragleave', (e) => {
// If leaving column list completely, remove indicator
if (!listEl.contains(e.relatedTarget)) {
if (dropIndicator.parentNode === listEl) {
listEl.removeChild(dropIndicator);
}
}
});
listEl.addEventListener('drop', (e) => {
e.preventDefault();
if (!draggedCardId) return;
const cardIndex = state.cards.findIndex(c => c.id === draggedCardId);
if (cardIndex === -1) return;
const targetCard = state.cards[cardIndex];
targetCard.column = colId;
// Determine destination index inside state.cards for ordering
const indicatorParent = dropIndicator.parentNode;
let insertBeforeId = null;
if (indicatorParent === listEl && dropIndicator.nextElementSibling) {
insertBeforeId = dropIndicator.nextElementSibling.dataset.id;
}
// Remove card and re-insert into array
state.cards.splice(cardIndex, 1);
if (insertBeforeId) {
const targetIndex = state.cards.findIndex(c => c.id === insertBeforeId);
if (targetIndex !== -1) {
state.cards.splice(targetIndex, 0, targetCard);
} else {
state.cards.push(targetCard);
}
} else {
state.cards.push(targetCard);
}
if (dropIndicator.parentNode) {
dropIndicator.parentNode.removeChild(dropIndicator);
}
renderBoard();
});
});
// Helper to calculate exact insert slot under cursor
function getDragAfterElement(container, y) {
const draggableElements = [...container.querySelectorAll('.card:not(.dragging):not(.hidden-by-search)')];
return draggableElements.reduce((closest, child) => {
const box = child.getBoundingClientRect();
const offset = y - box.top - box.height / 2;
if (offset < 0 && offset > closest.offset) {
return { offset: offset, element: child };
} else {
return closest;
}
}, { offset: Number.NEGATIVE_INFINITY }).element;
}
// Initial render
renderBoard();
</script>
</body>
</html>Reasoning trace (1,532 tokens)
**Developing Interactive Board** I'm currently focusing on building the core functionality for an interactive Kanban board using only vanilla JavaScript, HTML, and CSS. The aim is to implement drag-and-drop functionality for cards across the three specified columns: "To do," "In progress," and "Done," while ensuring the dynamic card count badges update accurately with each movement. Pre-populating with six realistic cards is also underway. **Implementing Core Features** I'm now focused on integrating drag-and-drop functionality for cards between columns, ensuring the placeholder accurately indicates drop zones. Work also continues on dynamically updating card counts and adding the delete button to each card, with a clean visual design in mind. **Styling and State** I'm detailing the UI themes, prioritizing color palettes and text contrast for both light and dark modes. I'm also defining the in-memory state structure for cards, including their properties and current column, and planning the initial header elements with their functionalities. **Implementing Drag and Drop** I'm deep in the weeds of the HTML5 Drag and Drop API, fine-tuning `dragstart` and `dragover` events to ensure a smooth, ghost-free visual indicator. My focus is on accurately determining drop positions within columns and between cards. Simultaneously, I'm setting up the modal and form structure for adding new cards. **Enhancing Card Functionality** I'm solidifying the delete card mechanism, opting for an immediate removal with a subtle visual transition rather than a `confirm()` prompt. Furthermore, I'm refining the search filtering to ensure card counts update gracefully and are visually represented.