* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Roboto', sans-serif;
}

body {
    background: #111827;
    color: #f9fafb;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

#container {
    background: #1f2937;
    border-radius: 16px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.5);
    padding: 30px 40px;
    width: 90%;
    max-width: 720px;
    text-align: center;
}

#container h1 {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    font-size: 2rem;
    margin-bottom: 25px;
    color: #d1fae5;
}

.buttonContainer {
    display: flex;
    justify-content: center;
    gap: 25px;
    margin-bottom: 30px;
}

.buttonContainer span {
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 500;
    color: #d1fae5;
    cursor: pointer;
    position: relative;
}

.buttonContainer input[type="checkbox"] {
    appearance: none;
    -webkit-appearance: none;
    width: 22px;
    height: 22px;
    border: 2px solid #6b7280;
    border-radius: 6px;
    background: #1f2937;
    cursor: pointer;
    position: relative;
    transition: all 0.2s ease-in-out;
}

.buttonContainer input[type="checkbox"]:checked {
    background: #10b981; 
    border-color: #10b981;
}

.buttonContainer input[type="checkbox"]:checked::after {
    content: "";
    position: absolute;
    top: 4px;
    left: 8px;
    width: 4px;
    height: 10px;
    border: solid #fff;
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
}

.buttonContainer label {
    cursor: pointer;
    user-select: none;
    font-size: 1rem;
}

#sqlJoinControlSvg {
    width: 100%;
    max-width: 600px;
    height: auto;
    margin: 0 auto 30px;
    display: block;
}

#leftCircle {
    transition: fill 0.3s ease;
}

#rightCircle {
    transition: fill 0.3s ease;
}

#intersectOfCircle {
    transition: fill 0.3s ease;
}

#leftCircleText,
#rightCircleText {
    pointer-events: none;
    font-weight: 700;
    fill: #f0fdf4;
}

.outputArea {
    min-height: 50px;
    margin-bottom: 20px;
    padding: 12px 16px;
    border-radius: 10px;
    background: #111827;
    color: #f0fdf4;
    font-size: 1rem;
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.6);
    text-align: left;
    white-space: pre-wrap; 
    font-family: monospace;
}

#copy {
    background: #10b981;
    color: #111827;
    border: none;
    padding: 12px 28px;
    border-radius: 10px;
    font-size: 1rem;
    cursor: pointer;
    font-weight: 500;
    transition: background 0.3s ease, transform 0.1s ease;
}

#copy:hover {
    background: #059669;
    transform: translateY(-2px);
}

#copy:active {
    transform: translateY(0);
    background: #047857;
}