* { margin: 0; padding: 0; box-sizing: border-box; }
body {
    background: #0e0e0e;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow-x: hidden;
    scroll-behavior: smooth;
}
img {
    margin-top: -4px;
    height: auto;
    position: relative;
    width: 100%;
    cursor: none;
}
#renderArea {
    width: 25%;
    justify-content: center;
}

#goToTopBtn {
    position: fixed;
    bottom: 20px;
    left: 20px;
    padding: 10px 15px;
    background: #333;
    color: #fff;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 14px;
    opacity: 0;
    transition: opacity 0.3s;
    z-index: 1000;
}

#goToTopBtn.show {
    opacity: 1;
}

#goToTopBtn:hover {
    background: #555;
}

#scrollInput {
    position: fixed;
    top: 20px;
    left: 60px;
    padding: 8px 12px;
    background: #333;
    color: #fff;
    border: 1px solid #555;
    border-radius: 5px;
    font-size: 14px;
    width: 150px;
    z-index: 1000;
    transition: opacity 0.3s, visibility 0.3s;
}

#scrollInput:focus {
    outline: none;
    border-color: #888;
    background: #444;
}

#hideMultiplierBtn {
    position: fixed;
    top: 20px;
    left: 20px;
    padding: 8px 12px;
    background: #333;
    color: #fff;
    border: 1px solid #555;
    border-radius: 5px;
    cursor: pointer;
    font-size: 14px;
    z-index: 1001;
    transition: background 0.3s, opacity 0.3s, visibility 0.3s;
}

#hideMultiplierBtn:hover {
    background: #555;
}

#scrollInput.hidden {
    opacity: 0;
    visibility: hidden;
}

#hideMultiplierBtn.hidden {
    opacity: 0;
    visibility: hidden;
}

#controlBar {
    position: fixed;
    top: 55px;
    left: 20px;
    background: #333;
    border: 1px solid #555;
    border-radius: 5px;
    padding: 8px 12px;
    display: flex;
    align-items: center;
    gap: 8px;
    z-index: 1000;
    transition: opacity 0.3s, visibility 0.3s;
}

#controlBar.hidden {
    opacity: 0;
    visibility: hidden;
}

#chapterInput {
    padding: 6px 8px;
    background: #444;
    color: #fff;
    border: 1px solid #555;
    border-radius: 3px;
    font-size: 14px;
    width: 60px;
}

#chapterInput:focus {
    outline: none;
    border-color: #888;
    background: #555;
}

.chapterBtn {
    padding: 6px 10px;
    background: #444;
    color: #fff;
    border: 1px solid #555;
    border-radius: 3px;
    cursor: pointer;
    font-size: 14px;
    transition: background 0.2s;
}

.chapterBtn:hover {
    background: #555;
}

.chapterBtn:active {
    background: #666;
}

@media (max-width: 1200px) {
    #renderArea { width: 35%; }
}
@media (max-width: 768px) {
    #renderArea { width: 50%; }
}
@media (max-width: 480px) {
    #renderArea { width: 100%; }
}