:root {
    --glass-bg: rgba(255, 255, 255, 0.1);
    --glass-border: rgba(255, 255, 255, 0.2);
    --button-bg: rgba(255, 255, 255, 0.1);
    --button-hover: rgba(255, 255, 255, 0.2);
    --button-active: rgba(255, 255, 255, 0.3);
    --text-color: #ffffff;
    --operation-color: #64ffda;
    --equals-color: #03dac6;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

/* Updates for body and container to improve layout */
body {
    min-height: 100vh; /* Using min-height instead of height */
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(45deg, #121212, #353535);
    overflow-x: hidden; /* Allow vertical scrolling if needed */
    position: relative;
    padding: 20px; /* Add padding to prevent content from touching edges */
}

body::before {
    content: '';
    position: absolute;
    height: 100%;
    width: 100%;
    background: radial-gradient(circle at center, transparent 0%, rgba(0, 0, 0, 0.8) 70%);
    z-index: 0;
}

/* Updates for body and container to improve layout */
.container {
    position: relative;
    z-index: 1;
    perspective: 1000px;
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 100%;
    max-width: 400px; /* Set max width for large screens */
}

.calculator {
    width: 320px;
    border-radius: 20px;
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    box-shadow: 0 25px 45px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    transform-style: preserve-3d;
    transform: rotateX(10deg) rotateY(0deg);
    transition: transform 0.5s ease;
}

.calculator:hover {
    transform: rotateX(5deg) rotateY(0deg) translateZ(10px);
}

.calculator-screen {
    width: 100%;
    padding: 20px;
    text-align: right;
    color: var(--text-color);
    background: rgba(0, 0, 0, 0.2);
    border-bottom: 1px solid var(--glass-border);
    perspective: 1000px;
    transform-style: preserve-3d;
}

.previous-operand {
    font-size: 1.2rem;
    opacity: 0.7;
    height: 24px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    color: rgba(255, 255, 255, 0.7);
}

.current-operand {
    font-size: 2.5rem;
    font-weight: 300;
    height: 60px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

/* Modified grid to accommodate more buttons */
.calculator-buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 8px;
    padding: 16px;
}

button {
    height: 60px;
    border: none;
    border-radius: 12px;
    background: var(--button-bg);
    color: var(--text-color);
    font-size: 1.5rem;
    cursor: pointer;
    outline: none;
    backdrop-filter: blur(5px);
    border: 1px solid var(--glass-border);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
    transform-style: preserve-3d;
    position: relative;
}

button::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border-radius: 12px;
    background: linear-gradient(
        to bottom,
        rgba(255, 255, 255, 0.1) 0%,
        rgba(255, 255, 255, 0) 50%
    );
    pointer-events: none;
}

button:hover {
    background: var(--button-hover);
    transform: translateY(-3px) translateZ(5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2);
}

button:active {
    background: var(--button-active);
    transform: translateY(0px) translateZ(0);
    box-shadow: 0 5px 10px rgba(0, 0, 0, 0.1);
}

.span-two {
    grid-column: span 2;
}

.operation {
    color: var(--operation-color);
    font-weight: 400;
    background: rgba(100, 255, 218, 0.1);
}

.equals {
    background: rgba(3, 218, 198, 0.2);
    color: var(--equals-color);
}

/* Error animation */
.error {
    animation: shake 0.4s ease-in-out;
}

@keyframes shake {
    0%, 100% {
        transform: translateX(0);
    }
    20%, 60% {
        transform: translateX(-5px);
    }
    40%, 80% {
        transform: translateX(5px);
    }
}

/* 3D press effect */
.button-pressed {
    transform: translateY(2px) translateZ(-2px) !important;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2) !important;
    transition: transform 0.1s, box-shadow 0.1s !important;
}

/* Responsive design */
@media (max-width: 375px) {
    .calculator {
        width: 280px;
    }
    
    .calculator-buttons {
        gap: 6px;
        padding: 12px;
    }
    
    button {
        height: 45px;
        font-size: 1.1rem;
    }
    
    .current-operand {
        font-size: 2rem;
        height: 50px;
    }
    
    .previous-operand {
        font-size: 1rem;
        height: 20px;
    }
    
    .calculator-footer {
        margin-top: 20px;
    }
}

/* Updated footer styles for consistent positioning */
.calculator-footer {
    margin-top: 20px; /* Adjusted margin as there's no history button anymore */
    margin-bottom: 10px;
    text-align: center;
    perspective: 1000px;
    transform-style: preserve-3d;
    width: 100%;
    position: relative;
}

.footer-text {
    font-size: 1rem;
    font-weight: 300;
    letter-spacing: 2px;
    color: var(--text-color);
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3),
                 0 4px 8px rgba(0, 0, 0, 0.2);
    background: var(--glass-bg);
    backdrop-filter: blur(8px);
    padding: 10px 20px;
    border-radius: 10px;
    display: inline-block;
    border: 1px solid var(--glass-border);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
    transform: rotateX(10deg) translateZ(10px);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.footer-text::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(
        90deg,
        rgba(255, 255, 255, 0) 0%,
        rgba(255, 255, 255, 0.1) 50%,
        rgba(255, 255, 255, 0) 100%
    );
    animation: shine 3s infinite;
}

.footer-text:hover {
    transform: rotateX(5deg) translateZ(15px);
    text-shadow: 0 4px 8px rgba(0, 0, 0, 0.4),
                 0 8px 16px rgba(0, 0, 0, 0.3);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.15),
                0 0 10px var(--equals-color);
    color: var(--equals-color);
}

@keyframes shine {
    0% {
        left: -100%;
    }
    20% {
        left: 100%;
    }
    100% {
        left: 100%;
    }
}

/* Responsive design for footer */
@media (max-width: 375px) {
    .calculator-footer {
        margin-top: 15px;
    }
    
    .footer-text {
        font-size: 0.85rem;
        padding: 8px 16px;
    }
}

/* Additional responsive adjustments for various screen sizes */
@media (max-height: 700px) {
    .calculator-footer {
        margin-top: 15px;
        margin-bottom: 5px;
    }
    
    .footer-text {
        padding: 6px 15px;
        font-size: 0.9rem;
    }
}

/* For very small screens */
@media (max-height: 600px) {
    .calculator {
        transform: scale(0.9);
        margin-bottom: -15px;
    }
    
    .calculator-footer {
        margin-top: 0;
    }
}

/* Floating background elements */
.container::before,
.container::after {
    content: '';
    position: absolute;
    width: 200px;
    height: 200px;
    border-radius: 50%;
    background: linear-gradient(45deg, #ff6b6b, #6b66ff);
    filter: blur(50px);
    opacity: 0.1;
    z-index: -1;
    animation: float 8s infinite alternate ease-in-out;
}

.container::before {
    top: -100px;
    right: -50px;
    animation-delay: 0s;
}

.container::after {
    bottom: -100px;
    left: -50px;
    background: linear-gradient(45deg, #6bffd8, #6ba1ff);
    animation-delay: 2s;
}

@keyframes float {
    0% {
        transform: translate(0, 0);
    }
    100% {
        transform: translate(20px, 20px);
    }
}

/* Toast notification for feedback */
.calculator-toast {
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    color: var(--equals-color);
    padding: 10px 20px;
    border-radius: 8px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
    font-size: 0.9rem;
    z-index: 1000;
    opacity: 0;
    transition: all 0.3s ease;
    text-align: center;
    border: 1px solid var(--equals-color);
}

.calculator-toast.show {
    transform: translateX(-50%) translateY(0);
    opacity: 1;
}