.control-panel {
    width: 34.375rem; /** 550px */
    flex: 0 0 auto;


    display: flex;
    flex-direction: column;
    justify-content: start;
    gap: var(--spacing-150);
}

.control-panel > *:not(:last-child) {
    padding-bottom: var(--spacing-50);
    border-bottom: var(--spacing-12_5) solid black;
}

/* settings */
fieldset {
    border: var(--spacing-12_5) solid black;
    padding: var(--spacing-50);
}

.measurement-units-panel, .rect-dimensions-form {
    display: flex;
    justify-content: space-evenly;
    gap: var(--spacing-50);
}
.measurement-unit {
    accent-color: black;
}

#rect-width-input, #rect-height-input {
    border: var(--spacing-12_5) solid black;
    width: 6.3rem; /* 100.8px */
    height: 2.5rem; /* 40px */
    padding-left: var(--spacing-100); /* 16px */
}
.apply-btn {
    color: white;
    background-color: black;
    border: var(--spacing-12_5) solid gray;
    padding: var(--spacing-50);
}
.apply-btn:hover {
    cursor: pointer;
}
.apply-btn:active {
    color: black;
    background-color: white;
    border: var(--spacing-12_5) solid black;
}
/* corner ellipses visivility */
input[type=checkbox] {
    accent-color: black;
    width: 1.3rem;
    height: 1.3rem;
}
/* ellipse corner */
.ellipse-knobs {
    display: grid;
    grid-template: auto auto / auto auto;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-50) var(--spacing-200);
}
.semi-axis-slider {
    accent-color: black;
}
.semi-axis-measurement {
    text-align: end;

    width: 10rem; /* 160px, can fit up to 5 digits along with the measurement unit */ 
    overflow: hidden;
    text-overflow: ellipsis;

    border: var(--spacing-12_5) solid black;
    padding: var(--spacing-50);
}
.css-declaration {
    display: block;
    position: relative;

    box-sizing: content-box;
    padding: var(--spacing-50) var(--spacing-200) var(--spacing-50) var(--spacing-50);
    margin-top: var(--spacing-50);

    background-color: var(--color-gray);

}
.shorthand-border-radius-property  {
    min-height: 2lh;
}
.copy-btn {
    all: initial;
    font-size: 1.875rem;
    position: absolute;
    right: var(--spacing-50);
    top: 0;
}
.copy-btn:hover {
    cursor: pointer;
}
.copy-btn:active {
    transform: scale(0.8);
}

@media (width < 1220px) {
    .control-panel {
        width: auto;
        min-width: min-content;

        display: grid;
        grid-template-columns: repeat(3, auto);
        grid-template-rows: repeat(3, auto);
        row-gap: unset;
    }
    .settings-panel {
        grid-row: 1 / 3;
    }
    .apply-btn {
        align-self: end;
    }
    .shorthand-border-radius-property {
        grid-column: 1 / 4;
        min-height: 1lh;
    }
    .control-panel > *:not(:last-child) {
        border: none;
    }
    .control-panel > *:nth-child(2), 
    .control-panel > *:nth-child(3) {
        border-bottom: var(--spacing-12_5) solid black;
        margin-bottom: var(--spacing-50);
    }
    
    .semi-axis-measurement {
        width: 5rem; /* 80px, can fit up to 6 digits along with decimal point */ 
    }
    .css-declaration:not(.shorthand-border-radius-property) {
        /* [TODO] stop updating the css corner readius properties using JS code */
        display: none;
    }
}