body {
    background-color: #000;
    color: #fff;
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
}

.header {
    padding: 16px;
    background: #111;
    text-align: center;
    position: relative;
}

.header .date, .header .title, .header .updated {
    margin: 4px 0;
}

.actions {
    position: absolute;
    top: 10px;
    right: 10px;
}

.icon {
    margin: 0 4px;
    background: #000;
    border: 1px solid #2f2f2f;
    color: #0f0;
    padding: 4px 8px;
    border-radius: 8px;
}

.history {
    background: #111;
    border: 1px solid #0f0;
    color: #0f0;
    padding: 6px 12px;
    border-radius: 6px;
}

.card {
    background: #1c1c1c;
    margin: 16px;
    padding: 16px;
    border-radius: 12px;
    text-align: center;
}

.percentage {
    font-size: 32px;
    font-weight: bold;
    color: limegreen;
    margin: 10px 0;
}

.note {
    font-size: 14px;
    color: gray;
}

.buttons {
    display: flex;
    justify-content: space-around;
    align-items: center;
    margin-top: 12px;
}

.btn-group button {
    font-size: 20px;
    margin: 0 4px;
    background: #000;
    border: 1px solid #0f0;
    color: #0f0;
    padding: 4px 8px;
    border-radius: 6px;
}

.delete {
    background: #c00;
    color: white;
    padding: 8px 12px;
    border: none;
    border-radius: 6px;
}

.nav {
    position: fixed;
    bottom: 0;
    width: 100%;
    display: flex;
    background: #000;
    justify-content: space-around;
    border-top: 1px solid #333;
}

.nav button {
    flex: 1;
    padding: 12px;
    background: none;
    color: #666;
    border: none;
    font-size: 16px;
}

.nav .active {
    color: #0f0;
}