* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'SF Pro Display', -apple-system, BlinkMacSystemFont, sans-serif;
        }

        body {
            background: linear-gradient(135deg, #0f0f12, #1a1a1d);
            min-height: 100vh;
            display: flex;
            justify-content: center;
            align-items: center;
            padding: 20px;
            color: white;
            overflow: hidden;
            position: relative;
        }

        /* Subtle animated background pattern */
        .background {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            pointer-events: none;
            z-index: -1;
        }

        .background::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: 
                radial-gradient(circle at 10% 20%, rgba(255, 255, 255, 0.03) 0%, transparent 20%),
                radial-gradient(circle at 90% 80%, rgba(255, 255, 255, 0.03) 0%, transparent 20%),
                radial-gradient(circle at 50% 50%, rgba(255, 255, 255, 0.02) 0%, transparent 30%);
            animation: bgAnimate 15s ease-in-out infinite;
        }

        @keyframes bgAnimate {
            0%, 100% { transform: translate(0, 0); }
            50% { transform: translate(5px, 5px); }
        }

        /* Liquid glassmorphism effect with multiple layers */
        .calculator {
            background: rgba(255, 255, 255, 0.03);
            backdrop-filter: blur(16px);
            -webkit-backdrop-filter: blur(16px);
            border: 1px solid rgba(255, 255, 255, 0.08);
            border-radius: 28px;
            padding: 28px;
            width: 90%;
            max-width: 380px;
            box-shadow: 
                0 10px 40px rgba(0, 0, 0, 0.3),
                0 0 40px rgba(255, 255, 255, 0.05);
            overflow: hidden;
            position: relative;
            transform: translateZ(0);
        }

        .calculator::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            border-radius: 28px;
            background: linear-gradient(45deg, 
                rgba(255, 255, 255, 0.03) 0%, 
                transparent 30%, 
                transparent 70%, 
                rgba(255, 255, 255, 0.03) 100%);
            pointer-events: none;
            animation: liquid 8s ease-in-out infinite;
        }

        @keyframes liquid {
            0% { background-position: 0% 50%; }
            50% { background-position: 100% 50%; }
            100% { background-position: 0% 50%; }
        }

        .title {
            text-align: center;
            margin-bottom: 24px;
            font-size: 1.5rem;
            color: #a0a0a0;
            letter-spacing: 0.5px;
            font-weight: 500;
            text-shadow: 0 0 10px rgba(0, 200, 100, 0.1);
        }

        .display-container {
            position: relative;
            margin-bottom: 24px;
            border-radius: 18px;
            overflow: hidden;
            background: rgba(0, 0, 0, 0.2);
            border: 1px solid rgba(255, 255, 255, 0.05);
        }

        .history {
            height: 28px;
            padding: 0 18px;
            font-size: 1rem;
            color: #a0a0a0;
            text-align: right;
            overflow: hidden;
            text-overflow: ellipsis;
            white-space: nowrap;
            line-height: 28px;
            font-weight: 300;
        }

        .current {
            min-height: 68px;
            padding: 20px 18px;
            font-size: 2.4rem;
            font-weight: 300;
            color: white;
            text-align: right;
            overflow: hidden;
            text-overflow: ellipsis;
            white-space: nowrap;
            line-height: 1.2;
            font-feature-settings: "tnum";
        }

        .buttons {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 14px;
        }

        .button {
            background: rgba(255, 255, 255, 0.08);
            border: none;
            border-radius: 18px;
            padding: 20px 5px;
            color: white;
            font-size: 1.3rem;
            cursor: pointer;
            transition: all 0.25s ease;
            font-weight: 500;
            letter-spacing: 0.5px;
            box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
            position: relative;
            overflow: hidden;
        }

        .button::before {
            content: '';
            position: absolute;
            top: -50%;
            left: -50%;
            width: 200%;
            height: 200%;
            background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, transparent 70%);
            opacity: 0;
            transition: opacity 0.3s ease;
            pointer-events: none;
        }

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

        .button:active {
            transform: translateY(2px);
            box-shadow: 0 2px 4px rgba(0, 0, 0, 0.15);
            background: rgba(255, 255, 255, 0.12);
        }

        .button:active::before {
            opacity: 0.3;
        }

        .clear {
            background: rgba(255, 80, 80, 0.15);
        }

        .equal {
            background: rgba(0, 200, 100, 0.15);
            grid-column: span 1;
        }

        .operator {
            background: rgba(255, 255, 255, 0.1);
        }

        .function {
            background: rgba(255, 255, 255, 0.08);
            font-size: 1.1rem;
        }

        .zero {
            grid-column: span 1;
        }

        /* Responsive design */
        @media (max-width: 480px) {
            .calculator {
                padding: 22px 18px;
                max-width: 95%;
            }
            
            .title {
                font-size: 1.3rem;
            }
            
            .current {
                font-size: 1.9rem;
                padding: 16px;
            }
            
            .history {
                font-size: 0.9rem;
                height: 24px;
            }
            
            .button {
                padding: 16px 5px;
                font-size: 1.2rem;
            }
        }

        @media (max-width: 375px) {
            .calculator {
                padding: 18px;
            }
            
            .button {
                padding: 14px 3px;
                font-size: 1rem;
            }
            
            .current {
                font-size: 1.7rem;
            }
        }

        /* Add subtle floating animation */
        .calculator {
            animation: float 6s ease-in-out infinite;
        }

        @keyframes float {
            0%, 100% { transform: translateY(0) scale(1); }
            50% { transform: translateY(-6px) scale(1.01); }
        }

        /* Better button press animation */
        .button-pressed {
            animation: buttonPress 0.2s ease;
        }

        @keyframes buttonPress {
            0% { transform: scale(1); }
            50% { transform: scale(0.95); }
            100% { transform: scale(1); }
        }

        /* Special styling for function buttons */
        .function {
            background: rgba(255, 255, 255, 0.08);
        }
        
        .function:hover {
            background: rgba(255, 255, 255, 0.12);
        }

        /* Calculator glass effect improvements */
        .calculator::after {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            border-radius: 28px;
            background: linear-gradient(135deg, 
                transparent 0%, 
                rgba(255, 255, 255, 0.05) 25%, 
                transparent 50%, 
                rgba(255, 255, 255, 0.05) 75%, 
                transparent 100%);
            pointer-events: none;
            opacity: 0.6;
        }
            /* HILANGKAN HIGHLIGHT BIRU SAAT DIKLIK */
        .button {
            -webkit-tap-highlight-color: transparent; /* Untuk mobile */
            outline: none; /* Untuk desktop */
            -webkit-user-select: none; /* Mencegah seleksi teks */
            -moz-user-select: none;
            -ms-user-select: none;
            user-select: none;
        }

        /* Tidak ada perubahan pada efek tombol yang ditekan */
        .button:active {
            transform: translateY(2px);
            box-shadow: 0 2px 4px rgba(0, 0, 0, 0.174);
            background: rgba(240, 235, 225, 0.144);
        }   
        .copyright {
            text-align: center;
            margin: 20px auto 0;
            font-size: 0.85rem;
            color: #998877;
            opacity: 0.85;
            letter-spacing: 0.5px;
            font-weight: 300;
            text-shadow: 0 1px 1px rgba(255, 255, 255, 0.6);
            max-width: 100%;
            padding: 0 10px;
        }