* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #667eea;
    --secondary-color: #764ba2;
    --accent-color: #f093fb;
    --text-color: #333;
    --text-light: #666;
    --background: #f8fafc;
    --card-bg: #ffffff;
    --border-color: #e2e8f0;
    --shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 15px 35px rgba(0, 0, 0, 0.15);
    --border-radius: 12px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

body {
    font-family: 'Poppins', sans-serif;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    color: var(--text-color);
}

.info-bar {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    position: relative;
    z-index: 100;
}

.info-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    color: var(--text-light);
}

.info-item i {
    color: var(--primary-color);
}

.calculator-container {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 2rem;
}

.calculator {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    padding: 2rem;
    width: 100%;
    max-width: 400px;
    transition: var(--transition);
}

.calculator:hover {
    box-shadow: var(--shadow-hover);
    transform: translateY(-2px);
}

.display-container {
    margin-bottom: 1.5rem;
    position: relative;
}

.display {
    width: 100%;
    height: 80px;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 1rem;
    font-size: 2rem;
    font-weight: 600;
    text-align: right;
    color: var(--text-color);
    background: var(--background);
    transition: var(--transition);
    font-family: 'Poppins', monospace;
}

.display:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.buttons-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1rem;
    grid-template-areas: 
        "clear clear divide multiply"
        "seven eight nine subtract"
        "four five six add"
        "one two three add"
        "zero zero decimal equals"
        "zero zero decimal equals";
}

.btn {
    height: 60px;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1.2rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
    font-family: 'Poppins', sans-serif;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    transition: left 0.5s;
}

.btn:hover::before {
    left: 100%;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}

.btn:active {
    transform: translateY(0);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.btn-number {
    background: var(--card-bg);
    color: var(--text-color);
    border: 2px solid var(--border-color);
}

.btn-number:hover {
    background: var(--background);
    border-color: var(--primary-color);
}

.btn-operator {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
}

.btn-operator:hover {
    background: linear-gradient(135deg, var(--secondary-color), var(--primary-color));
}

.btn-equals {
    background: linear-gradient(135deg, var(--accent-color), #f5576c);
    color: white;
    border: none;
    grid-area: equals;
}

.btn-equals:hover {
    background: linear-gradient(135deg, #f5576c, var(--accent-color));
}

.btn-clear {
    background: linear-gradient(135deg, #ff6b6b, #ee5a52);
    color: white;
    border: none;
    grid-column: span 2;
}

.btn-clear:hover {
    background: linear-gradient(135deg, #ee5a52, #ff6b6b);
}

.btn-zero {
    grid-column: span 2;
}

.btn-add {
    grid-row: span 2;
}

.footer {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    padding: 1.5rem 2rem;
    box-shadow: 0 -2px 10px rgba(0, 0, 0, 0.1);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
}

.footer-text {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    color: var(--text-light);
}

.footer-text i {
    color: var(--primary-color);
}

.main-domain-btn {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.main-domain-btn:hover {
    background: linear-gradient(135deg, var(--secondary-color), var(--primary-color));
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}

@media (max-width: 768px) {
    .info-bar {
        flex-direction: column;
        gap: 0.5rem;
        padding: 1rem;
    }
    
    .calculator-container {
        padding: 1rem;
    }
    
    .calculator {
        padding: 1.5rem;
    }
    
    .display {
        height: 70px;
        font-size: 1.8rem;
    }
    
    .btn {
        height: 50px;
        font-size: 1.1rem;
    }
    
    .buttons-grid {
        gap: 0.75rem;
    }
    
    .footer-content {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .calculator {
        padding: 1rem;
    }
    
    .display {
        height: 60px;
        font-size: 1.5rem;
    }
    
    .btn {
        height: 45px;
        font-size: 1rem;
    }
    
    .buttons-grid {
        gap: 0.5rem;
    }
}

@keyframes ripple {
    0% {
        transform: scale(0);
        opacity: 0.6;
    }
    100% {
        transform: scale(2);
        opacity: 0;
    }
}

.btn-ripple {
    position: absolute;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.6);
    animation: ripple 0.6s linear;
    pointer-events: none;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.calculator {
    animation: slideIn 0.5s ease-out;
}

.btn {
    animation: slideIn 0.5s ease-out;
}

.btn:nth-child(1) { animation-delay: 0.1s; }
.btn:nth-child(2) { animation-delay: 0.2s; }
.btn:nth-child(3) { animation-delay: 0.3s; }
.btn:nth-child(4) { animation-delay: 0.4s; }
.btn:nth-child(5) { animation-delay: 0.5s; }
.btn:nth-child(6) { animation-delay: 0.6s; }
.btn:nth-child(7) { animation-delay: 0.7s; }
.btn:nth-child(8) { animation-delay: 0.8s; }
.btn:nth-child(9) { animation-delay: 0.9s; }
.btn:nth-child(10) { animation-delay: 1.0s; }
.btn:nth-child(11) { animation-delay: 1.1s; }
.btn:nth-child(12) { animation-delay: 1.2s; }
.btn:nth-child(13) { animation-delay: 1.3s; }
.btn:nth-child(14) { animation-delay: 1.4s; }
.btn:nth-child(15) { animation-delay: 1.5s; }
.btn:nth-child(16) { animation-delay: 1.6s; }
.btn:nth-child(17) { animation-delay: 1.7s; }
.btn:nth-child(18) { animation-delay: 1.8s; }