/* --- Root Variables & Styling --- */
  body {
            font-family: 'Cormorant Garamond', serif;
            background-color: #f7f5f0;
            overflow-x: hidden;
        }
        .font-handwritten {
            font-family: 'Alex Brush', cursive;
        }
        .font-sans-alt {
            font-family: 'Montserrat', sans-serif;
        }

        /* 3D Envelope Wrapper Styles */
        #envelope-screen {
            background-color: #ffffff; /* White background */
            perspective: 1000px;
            transition: opacity 1s ease-in-out, visibility 1s;
        }

        .envelope-wrapper {
            position: relative;
            width: 300px;
            height: 200px;
            background-color: #f8f6f2; /* Soft white envelope base */
            box-shadow: 0 20px 40px rgba(0,0,0,0.15);
            cursor: pointer;
            transform-style: preserve-3d;
            transition: transform 0.5s ease;
        }

        .envelope-wrapper:hover {
            transform: translateY(-10px) rotateX(5px);
        }

        /* The Flap */
        .envelope-flap {
            position: absolute;
            top: 0;
            left: 0;
            width: 0;
            height: 0;
            border-left: 150px solid transparent;
            border-right: 150px solid transparent;
            border-top: 110px solid #e8e1d8; /* Light ivory flap */
            transform-origin: top;
            transition: transform 0.6s ease;
            z-index: 4;
        }

        /* Envelope Greeting Label */
        .envelope-greeting {
            position: absolute;
            top: 14px;
            left: 50%;
            transform: translateX(-50%);
            width: 90%;
            text-align: center;
            font-size: 0.6rem;
            letter-spacing: 0.15em;
            text-transform: uppercase;
            color: #545151;
            font-family: 'Montserrat', sans-serif;
            z-index: 5;
            pointer-events: none;
            white-space: nowrap;
            overflow: hidden;
            text-overflow: ellipsis;
        }

        /* Inner Letter Card */
        .letter-card {
            position: absolute;
            bottom: 5px;
            left: 15px;
            width: 270px;
            height: 180px;
            background-color: #fffdf9;
            z-index: 2;
            transition: transform 0.8s ease-in-out;
            padding: 20px;
            box-shadow: 0 0 10px rgba(0,0,0,0.1);
        }

        /* Front Pockets */
        .envelope-front {
            position: absolute;
            bottom: 0;
            left: 0;
            width: 0;
            height: 0;
            border-left: 150px solid #f3efe9;
            border-right: 150px solid #f3efe9;
            border-top: 100px solid transparent;
            z-index: 3;
        }
        .envelope-bottom {
            position: absolute;
            bottom: 0;
            left: 0;
            width: 0;
            height: 0;
            border-left: 150px solid transparent;
            border-right: 150px solid transparent;
            border-bottom: 100px solid #f0ece7;
            z-index: 3;
        }

        /* Wax Seal Stamp */
        .wax-seal {
            position: absolute;
            top: 95px;
            left: 135px;
            width: 30px;
            height: 30px;
            background-color: #b89246;
            border-radius: 50%;
            z-index: 5;
            box-shadow: 0 4px 6px rgba(0,0,0,0.3);
            transition: all 0.4s ease;
        }

        /* Open State Animations */
        .envelope-wrapper.open .envelope-flap {
            transform: rotateX(180deg);
            z-index: 1;
        }
        .envelope-wrapper.open .wax-seal {
            opacity: 0;
            transform: scale(0);
        }
        .envelope-wrapper.open .letter-card {
            transform: translateY(-120px);
            z-index: 5;
        }

        /* Audio Controls styling */
        #music-control {
            box-shadow: 0 4px 15px rgba(0,0,0,0.15);
        }