:root {
            --vermilion: #E84523;
            --dark: #1C1C1C;
            --offwhite: #FBF9F6;
            --fvbg: #E84523;
            --white: #FFFFFF;
        }

        html { scroll-behavior: smooth; }
        body {
            margin: 0; padding: 0; width: 100%; overflow-x: hidden;
            background-color: var(--offwhite);
            color: var(--dark);
        }
        ::selection { background: var(--vermilion); color: #fff; }

        ::-webkit-scrollbar { width: 6px; }
        ::-webkit-scrollbar-track { background: var(--offwhite); }
        ::-webkit-scrollbar-thumb { background: rgba(28, 28, 28, 0.2); border-radius: 10px; }
        ::-webkit-scrollbar-thumb:hover { background: var(--vermilion); }

        body::before {
            content: ""; position: fixed; top: 0; left: 0; width: 100%; height: 100%;
            background-image: url("https://grainy-gradients.vercel.app/noise.svg");
            opacity: 0.15; pointer-events: none; z-index: 9999;
        }

        /* Header Transitions */
        #mainHeader { 
            transition: all 0.5s cubic-bezier(0.16, 1, 0.3, 1);
            transform: translateY(-100%);
            opacity: 0;
            pointer-events: none;
        }
        #mainHeader.scrolled {
            transform: translateY(0);
            opacity: 1;
            pointer-events: auto;
            background-color: rgba(251, 249, 246, 0.95);
            backdrop-filter: blur(8px);
            border-bottom: 1px solid rgba(0,0,0,0.05);
            padding-top: 15px; padding-bottom: 15px;
        }
        
        #mainHeader .nav-link { color: var(--dark); transition: color 0.3s; }
        #mainHeader .nav-link:hover { color: var(--vermilion); }
        .hamburger-btn span { background-color: var(--dark); }

        #mainHeader.scrolled .nav-link { color: var(--dark); }
        #mainHeader.scrolled .nav-link:hover { color: var(--vermilion); }
        #mainHeader.scrolled .hamburger-btn span { background-color: var(--dark); }

        .section-reveal {
            opacity: 0; transform: translateY(30px);
            transition: all 1s cubic-bezier(0.16, 1, 0.3, 1);
        }
        .section-reveal.active { opacity: 1; transform: translateY(0); }

        .vertical-rl { writing-mode: vertical-rl; }
        .vertical-text { writing-mode: vertical-rl; text-orientation: upright; }

        /* FV (Hero Section) */
        .fv-section {
            position: relative;
            width: 100%;
            min-height: 100vh;
            background-color: var(--fvbg);
            display: flex;
            align-items: center;
            justify-content: center;
            overflow: hidden;
            padding: 128px 0; /* PC padding統一 (py-32相当) */
        }
        .fv-section::before {
            content: '';
            position: absolute;
            inset: -50%;
            background-image: url('data:image/svg+xml,%3Csvg width="40" height="40" viewBox="0 0 40 40" xmlns="http://www.w3.org/2000/svg"%3E%3Cpath d="M20 20.5V18H0v-2h20v-2H0v-2h20v-2H0V8h20V6H0V4h20V2H0V0h22v20h2V0h2v20h2V0h2v20h2V0h2v20h2V0h2v20h2v2H20v-1.5zM0 20h2v20H0V20zm4 0h2v20H4V20zm4 0h2v20H8V20zm4 0h2v20h-2V20zm4 0h2v20h-2V20zm4 4h20v2H20v-2zm0 4h20v2H20v-2zm0 4h20v2H20v-2zm0 4h20v2H20v-2z" fill="%23ffffff" fill-rule="evenodd"/%3E%3C/svg%3E');
            background-size: 60px 60px;
            z-index: 0;
            opacity: 0.07;
            transform: rotate(-45deg);
            pointer-events: none;
        }

        .fv-container {
            width: 100%;
            max-width: 1400px;
            margin: 0 auto;
            padding: 0 56px;
            display: grid;
            grid-template-columns: 0.45fr 0.55fr;
            gap: 60px;
            align-items: center;
            position: relative;
            z-index: 10;
        }

        .fv-left {
            position: relative;
            display: flex;
            align-items: center;
            justify-content: flex-start;
            min-height: 600px;
        }

        .fv-decorations {
            position: absolute;
            inset: 0;
            pointer-events: none;
            z-index: 1;
        }
        .fv-deco {
            position: absolute;
            opacity: 0;
            transition: opacity 1.2s ease, transform 1.2s ease;
            border-radius: 50%;
        }
        .fv-deco.show { opacity: 1; }
        .fv-deco-01 {
            top: 10%; right: 10%; width: clamp(100px, 15vw, 180px); aspect-ratio: 1;
            background: var(--white); opacity: 0 !important;
        }
        .fv-deco-01.show { opacity: 0.1 !important; }
        .fv-deco-02 {
            bottom: 5%; left: -10%; width: clamp(200px, 30vw, 300px); aspect-ratio: 1;
            border: 1px solid var(--white); opacity: 0 !important;
        }
        .fv-deco-02.show { opacity: 0.2 !important; }
        .fv-deco-03 {
            bottom: 25%; left: 45%; width: clamp(60px, 10vw, 100px); aspect-ratio: 1;
            background: var(--dark); opacity: 0 !important;
        }
        .fv-deco-03.show { opacity: 0.05 !important; }

        .fv-left-content {
            position: relative;
            z-index: 2;
            width: 100%;
            max-width: 520px;
            text-align: left;
        }

        .fv-catch, .fv-sub, .fv-logo-name, .fv-read-more { opacity: 0; }
        .fv-catch.is-active, .fv-sub.is-active, .fv-logo-name.is-active { opacity: 1; }

        .fv-catch {
            writing-mode: vertical-rl;
            font-size: clamp(26px, 3vw, 42px);
            font-weight: 700;
            line-height: 1.8;
            color: var(--dark);
            letter-spacing: 0.15em;
            text-shadow: 
                1.5px 1.5px 0 var(--white),
               -1.5px -1.5px 0 var(--white),
               -1.5px 1.5px 0 var(--white),
                1.5px -1.5px 0 var(--white),
                1.5px 0 0 var(--white),
               -1.5px 0 0 var(--white),
                0 1.5px 0 var(--white),
                0 -1.5px 0 var(--white),
                0 4px 15px rgba(0,0,0,0.2);
        }
        .fv-catch-line { display: block; overflow: hidden; }
        
        .char {
            display: inline-block;
            opacity: var(--opacity, 0);
            transform: translateY(var(--translate-y, 20px));
            transition: opacity 0.8s cubic-bezier(0.16, 1, 0.3, 1), transform 0.8s cubic-bezier(0.16, 1, 0.3, 1);
            transition-delay: calc(0.05s * var(--char-index));
        }
        .fv-catch.is-active .char { --opacity: 1; --translate-y: 0; }

        .fv-sub {
            writing-mode: vertical-rl;
            font-size: clamp(14px, 1.4vw, 16px);
            letter-spacing: 0.12em;
            color: var(--white);
            opacity: 0.9;
            line-height: 2.2;
            font-weight: 500;
            transition: opacity 1s ease, transform 1s ease;
            transform: translateX(15px);
        }
        .fv-sub.is-active { transform: translateX(0); }

        .fv-logo-name {
            font-size: 20px;
            font-weight: bold;
            letter-spacing: 0.2em;
            color: var(--white);
            margin-bottom: 32px;
            transition: opacity 1s ease 0.4s, transform 1s ease 0.4s;
            transform: translateY(15px);
            display: block;
        }
        .fv-logo-name.is-active { transform: translateY(0); }

        .fv-read-more {
            display: flex;
            flex-direction: column;
            align-items: flex-start;
            gap: 12px;
            margin-top: auto;
            transition: opacity 0.5s ease;
        }
        .fv-read-more.is-visible { opacity: 1; }
        .fv-read-more-line {
            width: 1px; height: 0;
            background-color: var(--white);
            opacity: 0.7;
        }
        .fv-read-more-line.animate { animation: lineGrow 1.2s ease-out forwards; }
        @keyframes lineGrow { from { height: 0; } to { height: 60px; } }
        
        .fv-read-more-text {
            font-family: 'Cormorant Garamond', serif;
            font-size: 11px;
            letter-spacing: 0.2em;
            color: var(--white);
            opacity: 0.8;
            text-transform: uppercase;
        }

        /* FV Right Grid */
        .fv-right {
            position: relative;
            width: 100%;
            height: 100%;
            display: flex;
            align-items: stretch;
        }
        .fv-image-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            grid-template-rows: 180px 280px 200px;
            gap: 16px;
            width: 100%;
            align-self: center;
        }
        .fv-grid-item {
            position: relative;
            overflow: hidden;
            opacity: 0;
            transform: translateY(20px);
            transition: opacity 0.8s ease, transform 0.8s ease;
            border-radius: 2px;
            box-shadow: 0 10px 30px rgba(0,0,0,0.15);
        }
        .fv-grid-item.show { opacity: 1; transform: translateY(0); }
        
        .fv-grid-item img {
            width: 100%; height: 100%;
            object-fit: cover;
            display: block;
            filter: grayscale(10%) brightness(0.95);
            transition: filter 0.5s ease, transform 1s ease;
        }
        .fv-grid-item:hover img {
            filter: grayscale(0%) brightness(1);
            transform: scale(1.05);
        }

        .fv-grid-1 { grid-column: 2 / 3; grid-row: 1 / 2; }
        .fv-grid-2 { grid-column: 3 / 4; grid-row: 1 / 3; }
        .fv-grid-3 { grid-column: 1 / 3; grid-row: 2 / 3; }
        .fv-grid-4 { grid-column: 1 / 2; grid-row: 3 / 4; }
        .fv-grid-5 { grid-column: 2 / 3; grid-row: 3 / 4; }
        .fv-grid-6 { grid-column: 3 / 4; grid-row: 3 / 4; }

        @media (min-width: 1025px) {
            .fv-right { width: 115%; max-width: 115%; margin-left: -5%; }
        }
        @media (max-width: 900px) {
            .fv-section { padding: 40px 0; } /* SP padding */
            .fv-container { display: flex; flex-direction: column; gap: 0; padding: 0 24px; }
            .fv-left { min-height: auto; padding-left: 0; }
            .fv-decorations { top: 0; left: 0; right: 0; bottom: 0; height: 100%; }
            .fv-deco-01 { top: auto; bottom: 5%; right: 0%; width: 140px; }
            .fv-deco-02 { top: auto; bottom: 0%; right: -10%; width: 180px; }
            .fv-deco-03 { top: auto; bottom: 15%; right: 15%; width: 60px; }
            .fv-catch { font-size: clamp(24px, 6vw, 32px); margin-bottom: 16px; }
            .fv-sub { margin-bottom: 24px; }
            .fv-logo-name { margin-bottom: 32px; }
            .fv-read-more { display: none; }
            .fv-right { min-height: 400px; width: 100%; margin-left: 0; margin-top: 24px; }
            .fv-image-grid { grid-template-rows: 120px 220px 140px; gap: 8px; }
        }

        .service-image-fixed {
            transition: opacity 1s cubic-bezier(0.16, 1, 0.3, 1);
            will-change: opacity;
        }

        /* Hamburger icon toggle */
        .hamburger-btn {
            display: flex; flex-direction: column; justify-content: center; align-items: center;
            width: 44px; height: 44px; background: transparent; border: none;
            cursor: pointer; z-index: 2000; position: relative; padding: 0;
        }
        .hamburger-btn span {
            display: block; position: absolute; left: 8px; width: 28px; height: 2px;
            transition: all 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
        }
        .hamburger-btn span:nth-child(1) { top: 14px; }
        .hamburger-btn span:nth-child(2) { top: 21px; }
        .hamburger-btn span:nth-child(3) { top: 28px; }
        .hamburger-btn.is-active span:nth-child(1) { top: 21px; transform: rotate(45deg); background-color: var(--dark) !important;}
        .hamburger-btn.is-active span:nth-child(2) { opacity: 0; }
        .hamburger-btn.is-active span:nth-child(3) { top: 21px; transform: rotate(-45deg); background-color: var(--dark) !important;}
        #mainHeader.scrolled .hamburger-btn.is-active span { background-color: var(--dark) !important; }