body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    text-align: center;
    margin: 0;
    padding: 20px;
    min-height: 100vh;
    background: url('https://www.transparenttextures.com/patterns/diamond-upholstery.png'), linear-gradient(to bottom, #1e3c72, #2a5298,#1550bd);
    background-size: 25% 25%;
    animation: gradientBG 15s ease infinite;
}



@keyframes gradientBG {
    0% {
        background-position: 0% 100%;
    }
    0% {
        background-position: 100% 0%;
    }
    0% {
        background-position: 0% 100%;
    }
}

.container {
    background-color: rgba(162, 134, 134, 0.9);
    border-radius: 15px;
    padding: 25px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    max-width: 900px;
    margin: 0 auto;
    backdrop-filter: blur(5px);
    border: 1px solid rgba(255, 255, 255, 0.3);
}

/* Rest of your existing CSS remains the same */
h1 {
    color: #3a4a6d;
    text-shadow: 1px 1px 2px rgba(0,0,0,0.1);
    margin-bottom: 30px;
}

.top-container {
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 30px 0;
}

.top-box {
    border: 3px solid #3a4a6d;
    border-radius: 10px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 24px;
    background-color: #ff7e5f;
    color: white;
    font-weight: bold;
    width: 67px;
    height: 67px;
    margin-left: 15px;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
    transition: all 0.3s ease;
}

/* ... rest of your existing CSS ... */

.top-container span {
    font-size: 22px;
    font-weight: 600;
    color: #3a4a6d;
}

.stack-container {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    max-width: 90vw;
    margin: 0 auto;
    gap: 15px;
    row-gap: 50px;
    padding: 20px 0;
}

.stack-element {
    transition: all 0.3s ease;
    box-sizing: border-box;
    border: 3px solid #3a4a6d;
    border-radius: 10px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 22px;
    background: linear-gradient(145deg, #ffffff 0%, #e6e9f0 100%);
    color: #3a4a6d;
    width: 70px;
    height: 70px;
    position: relative;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
    transition: all 0.3s ease;
}

.stack-element:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 12px rgba(0,0,0,0.15);
}

.index-label {
    font-size: 14px;
    font-weight: 600;
    position: absolute;
    bottom: -25px;
    width: 100%;
    text-align: center;
    color: #5a6a8a;
}

.circle {
    position: absolute;
    border-radius: 50%;
    border: 3px solid #dbea57;
    width: 70px;
    height: 70px;
    transition: all 1s ease-in-out;
    box-shadow: 0 4px 15px rgba(255, 126, 95, 0.4);
}

.controls {
    margin-bottom: 30px;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px;
}

input {
    padding: 12px 15px;
    font-size: 16px;
    border: 2px solid #d1d9e6;
    border-radius: 8px;
    width: 150px;
    transition: all 0.3s ease;
    background-color: #f8f9fa;
}

input:focus {
    outline: none;
    border-color: #3a4a6d;
    box-shadow: 0 0 0 3px rgba(58, 74, 109, 0.2);
}

/* ... (keep all your existing styles above) ... */

/* ... (keep all your existing styles above) ... */

/* Enhanced CSS3 Buttons */
button {
    padding: 12px 24px;
    font-size: 16px;
    font-weight: 600;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    text-transform: uppercase;
    letter-spacing: 1px;
    z-index: 1;
}

button::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    transition: all 0.3s ease;
    opacity: 0;
}

button:hover::before {
    opacity: 1;
}

button:active {
    transform: translateY(2px);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

/* Create Stack Button */
#createBtn {
    background: linear-gradient(to right, #4e7cff, #6a5acd);
    color: white;
    border: 2px solid #4e7cff;
}

#createBtn::before {
    background: linear-gradient(to right, #6a5acd, #4e7cff);
}

/* Push Button */
#pushBtn {
    background: linear-gradient(to right, #6bd2a2, #4CAF50);
    color: white;
    border: 2px solid #6bd2a2;
}

#pushBtn::before {
    background: linear-gradient(to right, #4CAF50, #6bd2a2);
}

/* Pop Button */
#popBtn {
    background: linear-gradient(to right, #ff7e5f, #ff4d4d);
    color: white;
    border: 2px solid #ff7e5f;
}

#popBtn::before {
    background: linear-gradient(to right, #ff4d4d, #ff7e5f);
}

/* Clear Button */
#clearBtn {
    background: linear-gradient(to right, #a1a8c3, #7a7f8f);
    color: white;
    border: 2px solid #a1a8c3;
}

#clearBtn::before {
    background: linear-gradient(to right, #7a7f8f, #a1a8c3);
}

/* Hover Effects for All Buttons */
#createBtn:hover, #pushBtn:hover, #popBtn:hover, #clearBtn:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
    color: white;
}

/* Pulse Animation on Click */
@keyframes pulse {
    0% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
    100% {
        transform: scale(1);
    }
}

button:focus {
    animation: pulse 0.5s ease;
    outline: none;
}

/* Responsive Buttons */
@media (max-width: 600px) {
    button {
        padding: 10px 16px;
        font-size: 14px;
    }
}

/* Add this to your existing styles */
#peekBtn {
    background-color: #9b59b6; /* Purple */
}
#peekBtn:hover {
    background-color: #8e44ad;
}

.peek-value {
    margin-top: 20px;
    padding: 10px;
    font-size: 18px;
    font-weight: bold;
    color: #2c3e50;
    min-height: 24px;
}

/* Keep all your existing button styles */
/* ... rest of your CSS ... */
/* Add this to your existing styles */
.circle {
    position: absolute;
    border-radius: 50%;
    border: 5px solid #7a3dea;
    width: 70px;
    height: 70px;
    transition: transform 1s ease-in-out;
    box-shadow: 0 4px 15px rgba(192, 122, 105, 0.4);
    z-index: 100; /* Ensure it appears above other elements */
    pointer-events: none; /* Prevent interaction with the circle */
    box-sizing: border-box; /* Include border in dimensions */
}


.peek-highlight {
    position: relative;
    animation: pulseHighlight 1s ease-in-out;
    border: 7px solid #9b59b6 !important;
    box-shadow: 0 0 0 3px rgba(155, 89, 182, 0.3);
}

@keyframes pulseHighlight {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}