body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: #f4f4f4;
    color: #333;
    margin: 0;
    padding: 20px;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    background-color: #fff;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
}

h1 {
    text-align: center;
    color: #2c3e50;
}

.input-container {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-bottom: 30px;
}

#topic-input, #update-input {
    width: 100%;
    padding: 12px;
    border: 1px solid #ccc;
    border-radius: 5px;
    box-sizing: border-box;
    font-size: 1rem;
}

#update-input {
    resize: vertical;
    min-height: 70px;
}

#add-btn {
    padding: 12px 15px;
    background-color: #3498db;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: bold;
    transition: background-color 0.2s;
}

#add-btn:hover {
    background-color: #2980b9;
}

.boards {
    display: flex;
    justify-content: space-between;
    gap: 20px;
}

.board {
    flex: 1;
    background-color: #f9f9f9;
    padding: 15px;
    border-radius: 5px;
    border: 1px solid #e0e0e0;
}

.board h2 {
    text-align: center;
    font-size: 1.2rem;
    color: #34495e;
    margin-top: 0;
}

.tasks {
    min-height: 200px;
    padding: 10px;
}

.task {
    background-color: #fff;
    padding: 15px;
    margin-bottom: 10px;
    border-radius: 5px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.08);
    cursor: grab;
    font-size: 0.95rem;
    line-height: 1.4;
}

.task:active {
    cursor: grabbing;
}

.topic-group {
    background-color: #e9ecef;
    border-radius: 5px;
    padding: 10px;
    margin-bottom: 15px;
}

.topic-group h3 {
    margin-top: 0;
    padding-bottom: 10px;
    border-bottom: 1px solid #ccc;
    font-size: 1rem;
    color: #495057;
}