.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: white;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    z-index: 1000;
    transition: opacity 0.5s ease;
    cursor: pointer;
    perspective: 1000px;
}

/* Position all envelope elements relative to center */
.envelope-flap-wrapper,
.inner-content,
.envelope-back {
    position: absolute;
    top: calc(50% - 80px);
    left: calc(50% - 120px);
    width: 240px;
    height: 160px;
}

.letter {
    position: absolute;
    top: calc(50% - 64px);
    left: calc(50% - 96px);
    width: 192px;
    height: 128px;
    z-index: 30;
}

.envelope-flap-wrapper {
    z-index: 10;
}

.envelope-flap {
    height: 100%;
    width: 100%;
    background: #c5d1d8;
    clip-path: polygon(0% 0%, 48% 75%, 52% 75%, 100% 0%);
}

.inner-content {
    background: #d8e1e7;
    clip-path: polygon(0 0, 0% 100%, 100% 100%, 100% 0, 90% 0, 60% 40%, 40% 40%, 10% 0);
    z-index: 20;
}

.envelope-back {
    background: #c5d1d8;
    border: 1px solid rgba(69, 95, 111, 0.24);
    box-shadow: 0 12px 30px rgba(38, 63, 77, 0.18);
    position: absolute;
    top: calc(50% - 80px);
    left: calc(50% - 120px);
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    align-items: flex-start;
    text-align: left;
    font-family: 'Courier New', monospace;
    font-size: 1.2em;
    padding: 30px;
    box-sizing: border-box;
    transform-style: preserve-3d;
    z-index: 50;
    overflow: hidden;
}

.envelope-back-title {
    color: #333;
    transform-style: preserve-3d;
    backface-visibility: visible;
    position: absolute;
    top: 100px;
    left: 50%;
    transform: translate(-50%, -50%);
    max-width: 200px;
    word-wrap: break-word;
    font-size: 0.9em;
    text-align: center;
}

/* Before the turn, paint the address side as one solid sheet. */
.loading-overlay:not(.open) > .envelope-back {
    transform-style: flat;
    perspective: none;
}

#loading-spinner {
    position: absolute;
    bottom: 15%;
    left: 50%;
    transform: translateX(-50%);
    font-size: 24px;
    color: #555;
    cursor: pointer;
    opacity: 1;
    white-space: nowrap;
    text-align: center;
    font-family: Arial, sans-serif;
}

#click-to-open {
    position: absolute;
    bottom: 20%;
    left: 50%;
    transform: translateX(-50%);
    font-size: 24px;
    color: #555;
    cursor: pointer;
    opacity: 0;
    transition: opacity 0.5s ease-in;
    white-space: nowrap;
    text-align: center;
    font-family: Arial, sans-serif;
}

.click-to-open.hidden {
    display: none;
    opacity: 0;
}

.letter-content {
    position: absolute;
    top: 0;
    left: 0;
    height: 100%;
    width: 100%;
    transform: translate(0, 0);
}

.loading-overlay.open .envelope-back,
.loading-overlay.open .envelope-back-title {
    animation: turnAround 1.2s ease-out forwards;
    transform-style: preserve-3d;
    backface-visibility: visible;
    transform-origin: center center;
}

@keyframes turnAround {
    0% {
        transform: rotateY(0deg);
        z-index: 50;
    }

    100% {
        transform: rotateY(180deg);
        z-index: 10;
    }
}

.loading-overlay.open .envelope-back-title {
    animation: none;
    transform-style: inherit;
    backface-visibility: visible;
}

.loading-overlay.open .inner-content {
    animation: innerTurnAround 1.2s ease-out forwards;
    transform-style: preserve-3d;
    backface-visibility: visible;
    transform-origin: center center;
}

@keyframes innerTurnAround {
    0% {
        transform: rotateY(0deg);
        z-index: 20;
    }

    100% {
        transform: rotateY(180deg);
        z-index: 40;
    }
}

.loading-overlay.open .envelope-flap-wrapper,
.loading-overlay.open .envelope-flap {
    animation: flapTurnAndOpen 2.4s ease-out forwards;
    transform-style: preserve-3d;
    backface-visibility: visible;
}

/* Combined animation for flap that includes both turning and opening */
@keyframes flapTurnAndOpen {

    /* First part: turn around (0-50%) */
    0% {
        transform: rotateY(0deg);
        transform-origin: center center;
        opacity: 1;
        z-index: 10;
    }

    50% {
        transform: rotateY(180deg) rotateX(0deg);
        transform-origin: top;
        opacity: 1;
        z-index: 50;
    }

    99% {
        transform: rotateY(180deg) rotateX(180deg);
        transform-origin: top;
        z-index: 50;
    }

    100% {
        transform: rotateY(180deg) rotateX(180deg);
        transform-origin: top;
        z-index: 10;
    }
}

.loading-overlay.open .envelope-flap {
    animation: flapOpen 1s forwards 1.2s;
}

@keyframes flapOpen {
    0% {
        background: #c5d1d8;
    }

    100% {
        background: #d8e1e7;
    }
}

.loading-overlay.open .letter {
    animation: flyOut 6s ease-out forwards;
    transform-style: preserve-3d;
    backface-visibility: visible;
}

@keyframes flyOut {
    0% {
        transform: rotateY(0deg);
        width: 192px;
        height: 128px;
        left: calc(50% - 96px);
        z-index: 25;
    }

    10% {
        width: 192px;
        height: 128px;
        z-index: 25;
    }

    20% {
        top: calc(50% - 70px);
        transform: rotateY(180deg);
        width: 192px;
        height: 128px;
        z-index: 30;
    }

    /*this time we need to wait for the envelope to be opened*/
    40% {
        top: calc(50% - 70px);
        transform: rotateY(180deg);
        width: 192px;
        height: 128px;
        z-index: 30;
    }

    45% {
        top: 20%;
        width: 192px;
        height: 128px;
        z-index: 30;
    }

    46% {
        z-index: 60;
    }

    55% {
        top: 50%;
        left: calc(50% - 96px);
    }

    100% {
        transform: rotateY(180deg);
        top: 0;
        left: 0;
        height: 100%;
        width: 100%;
        z-index: 60;
    }
}

.envelopeBackground {
    position: relative;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    background-size: cover;
    background-position: center center;
    background-repeat: no-repeat;
    transform: scaleX(-1);
}

.background {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: center;
    z-index: -1;
}

.letter,
.letter-content,
.envelopeBackground,
.envelope-flap-wrapper,
.envelope-flap,
.inner-content,
.envelope-back,
.envelope-back-title {
    transform-style: preserve-3d;
    perspective: 1000px;
}

.postal-stamp {
    position: absolute;
    top: 15px;
    right: 15px;
    width: 60px;
    height: 60px;
    z-index: 60;
}