html, body {
            margin: 0;
            padding: 0;
            width: 100%;
            height: 100%;
            overflow: hidden; /* Shio: Force no scroll on body level */
            overscroll-behavior: none; /* Prevent rubber-banding on Mac/iOS */
        }

        body {
            font-family: 'Noto Sans JP', sans-serif;
            color: #333;
        }

        /* --- LAYOUT --- */
        #main-container {
            display: grid;
            grid-template-columns: 1fr auto;
            /* Shio: Use dvh for mobile browser address bar adaptability */
            height: 100dvh;
            width: 100vw;
            overflow: hidden; /* Clip anything outside, specifically the debug panel */
            position: relative;
            transition: grid-template-columns 0.6s cubic-bezier(0.16, 1, 0.3, 1);
        }

        #main-container.debug-hidden {
            grid-template-columns: 1fr 0px;
        }

        #content-column {
            position: relative;
            width: 100%;
            height: 100%;
            display: flex;
            justify-content: center;
            align-items: center;
            overflow: hidden;
        }

        /* --- BACKGROUND --- */
        #background-canvas {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            z-index: -1;
            transform: scale(1.05); /* Slightly larger scale to accommodate tilt parallax */
        }

        /* --- TYPOGRAPHY --- */
        #text-overlay {
            position: relative;
            z-index: 10;
            padding: 2rem;
            width: 100%;
            max-width: 90dvw;
            text-align: left;
            mix-blend-mode: multiply;

            opacity: 0;
            transform: translateY(20px);
            animation: fadeInUp 1.5s cubic-bezier(0.2, 0.8, 0.2, 1) forwards;
            animation-delay: 0.2s;
        }

        .covenant-text {
            /* Responsive sizing: min 2.5rem, pref 5vw, max 5rem */
            font-size: clamp(2.5rem, 5vw, 5rem);
            line-height: 1.2;
            font-weight: 300;
            font-family: "Noto Sans JP", sans-serif;
            letter-spacing: 0.05em;
            color: #2d3748;
        }

        .covenant-part {
            white-space: nowrap;
            text-overflow: ellipsis;
        }

        /* Line Break Logic */
        .mobile-break {
            display: none; /* Hidden on desktop */
        }

        .covenant-sub {
            font-size: clamp(1rem, 2vw, 1.5rem);
            margin-top: 2rem;
            font-weight: 400;
            color: #555;
            opacity: 0.8;
            letter-spacing: 0.05em;
        }

        /* English specific typography for the subtext */
        /* Shio: Refined typography using Lato */
        .covenant-en {
            font-family: 'Lato', sans-serif;
            font-weight: 300;
            letter-spacing: 0.04em;
            margin-right: 0.3em;
            font-style: normal;
        }

        @keyframes fadeInUp {
            to { opacity: 1; transform: translateY(0); }
        }

        /* --- DEBUG PANEL --- */
        #debug-column {
            background: rgba(255, 255, 255, 0.7);
            backdrop-filter: blur(20px);
            -webkit-backdrop-filter: blur(20px);
            border-left: 1px solid rgba(255, 255, 255, 0.4);
            box-shadow: -5px 0 20px rgba(0,0,0,0.05);
            padding: 2rem;
            overflow-y: auto;
            width: 360px;
            opacity: 1;
            transform: translateX(0);
            transition: all 0.6s cubic-bezier(0.16, 1, 0.3, 1);
            z-index: 50;
            box-sizing: border-box;
        }

        #main-container.debug-hidden #debug-column {
            opacity: 0;
            padding: 0;
            width: 0;
            overflow: hidden;
            display: none;
        }

        /* --- RESPONSIVE MOBILE --- */
        @media (max-width: 768px) {
            #main-container {
                display: block; /* Stack layout */
            }

            /* Debug column becomes an overlay drawer */
            #debug-column {
                position: absolute;
                top: 0;
                right: 0;
                height: 100%;
                width: 85%;
                max-width: 320px;
                /* Reset transform transition logic for drawer behavior */
            }

            /* Off-screen translation for hidden state */
            #main-container.debug-hidden #debug-column {
                width: 85%;
                transform: translateX(100%); /* Move completely off-screen */
                opacity: 1;
                padding: 2rem;
                pointer-events: none; /* Ensure clicks pass through when hidden */
            }

            /* Enable specific line break on mobile */
            .mobile-break {
                display: inline;
            }

            /* Adjust padding for mobile to avoid edge touching */
            #text-overlay {
                padding: 1.5rem;
            }
        }

        /* --- TOP NAVBAR --- */
        #top-nav-area {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 60px;
            z-index: 200;
            display: flex;
            justify-content: center;
            align-items: flex-start;
        }

        #top-nav {
            margin-top: 1rem;
            background: rgba(255, 255, 255, 0.4);
            backdrop-filter: blur(12px);
            -webkit-backdrop-filter: blur(12px);
            border: 1px solid rgba(255, 255, 255, 0.5);
            padding: 0.5rem 2rem;
            border-radius: 2rem;
            display: flex;
            gap: 2rem;
            opacity: 0;
            transform: translateY(-20px);
            transition: all 0.4s cubic-bezier(0.16, 1, 0.3, 1);
            box-shadow: 0 4px 15px rgba(0,0,0,0.05);
            pointer-events: auto;
        }

        @media (hover: hover) and (pointer: fine) {
            #top-nav-area:hover #top-nav {
                opacity: 1;
                transform: translateY(0);
            }
        }

        #top-nav.visible {
            opacity: 1;
            transform: translateY(0);
        }

        #top-nav a {
            text-decoration: none;
            color: #4a5568;
            font-weight: 500;
            font-size: 0.95rem;
            letter-spacing: 0.05em;
            transition: color 0.2s, transform 0.2s;
            font-family: 'Lato', sans-serif;
        }

        #top-nav a:hover {
            color: #8b5cf6;
            transform: scale(1.05);
        }

        /* Toggle button */
        #toggle-debug {
            position: fixed;
            top: 1.5rem;
            right: 1.5rem;
            z-index: 100;
            background: rgba(255, 255, 255, 0.4);
            backdrop-filter: blur(4px);
            border: 1px solid rgba(255, 255, 255, 0.5);
            color: #4a5568;
            transition: all 0.2s ease;
            padding: 0 !important;
            display: flex !important;
            align-items: center !important;
            justify-content: center !important;
        }
        #toggle-debug:hover {
            background: rgba(255, 255, 255, 0.9);
            transform: scale(1.05);
        }
        #toggle-debug svg {
            position: static !important;
            transform: none !important;
            margin: 0 !important;
            display: block !important;
        }

        /* Sliders */
        input[type=range] { -webkit-appearance: none; background: transparent; }
        input[type=range]::-webkit-slider-thumb {
            -webkit-appearance: none; height: 16px; width: 16px;
            border-radius: 50%; background: #8b5cf6; cursor: pointer;
            margin-top: -6px; box-shadow: 0 1px 3px rgba(0,0,0,0.3);
        }
        input[type=range]::-webkit-slider-runnable-track {
            width: 100%; height: 4px; cursor: pointer;
            background: #cbd5e0; border-radius: 2px;
        }