body {
    font-family: 'Segoe UI', sans-serif;
    background: #f7f9fc;
    color: #333;
    padding: 20px;
    margin: 0;
}

.container {
    max-width: 700px;
    margin: auto;
    background: white;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.controls {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    margin-bottom: 20px;
}

#calendar {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 10px;
}

.day {
    background: #ecf0f3;
    border-radius: 8px;
    padding: 20px 0;
    text-align: center;
    font-weight: bold;
    cursor: pointer;
    position: relative;
    transition: background 0.3s, transform 0.3s;
}

.day:hover {
    background: #dbe6f1;
    transform: scale(1.05);
}

.day.has-task::after {
    content: "📌";
    position: absolute;
    top: 5px;
    right: 8px;
}

.popup {
    position: fixed;
    top: 15%;
    left: 50%;
    transform: translateX(-50%);
    background: white;
    padding: 25px;
    border-radius: 12px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.2);
    max-width: 400px;
    width: 90%;
    z-index: 100;
}

.hidden {
    display: none;
}

#task-list {
    list-style: none;
    padding-left: 0;
    margin-bottom: 20px;
}

#task-list li {
    padding: 8px;
    border-bottom: 1px solid #ddd;
}

button {
    background: #3498db;
    border: none;
    color: white;
    padding: 10px 15px;
    border-radius: 6px;
    cursor: pointer;
}

button:hover {
    opacity: 0.9;
}

footer {
    text-align: center;
    margin-top: 30px;
    color: #777;
}