/* Reset & Base */
:root {
    --bg-color: #FAFAF8;
    /* Warm off-white */
    --text-color: #333333;
    /* Deep Charcoal */
    --text-light: #767676;
    --accent-color: #8C8C88;
    /* Mute Olive/Grey */
    --accent-warm: #C17E60;
    /* Terracotta hint */
    --font-en: 'Inter', 'Helvetica Neue', Arial, sans-serif;
    --font-jp: 'Noto Sans JP', sans-serif;
    --container-width: 1200px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: var(--font-jp);
    /* Default to JP for body readability */
    line-height: 2.0;
    /* Spacious reading */
    -webkit-font-smoothing: antialiased;
    font-weight: 300;
    letter-spacing: 0.05em;
}

h1,
h2,
h3,
h4 {
    font-weight: 400;
    margin: 0;
}

a {
    text-decoration: none;
    color: inherit;
    transition: all 0.4s ease;
}

.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 40px;
    position: relative;
    z-index: 2;
}

.container-narrow {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 40px;
}

.container-large {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 40px;
}

/* Typography Hierarchy (Karst Goods Style) */
.en-title {
    font-family: var(--font-en);
    font-weight: 400;
    /* Regular */
    text-transform: uppercase;
    letter-spacing: 0.02em;
    /* Tight tracking */
    margin-bottom: 24px;
    font-size: 0.9rem;
    /* Section label size */
    color: var(--text-light);
    display: block;
}

.en-title-large {
    font-family: var(--font-en);
    font-weight: 300;
    /* Light */
    text-transform: uppercase;
    letter-spacing: -0.02em;
    /* Chic tight */
    font-size: 4.5rem;
    /* H1 Size */
    line-height: 1.1;
    color: #fff;
    margin-bottom: 32px;
}

.en-section-title {
    font-family: var(--font-en);
    font-weight: 400;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-size: 3rem;
    /* H2 Size */
    margin-bottom: 32px;
    line-height: 1.1;
    color: var(--text-color);
}

.jp-lead {
    font-family: var(--font-jp);
    font-weight: 500;
    /* Medium for contrast */
    font-size: 1.6rem;
    line-height: 1.6;
    margin-bottom: 40px;
    color: var(--text-color);
}

.jp-body {
    font-family: var(--font-jp);
    font-weight: 300;
    font-size: 1rem;
    line-height: 2.2;
    color: var(--text-light);
}

/* Header */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    padding: 32px 40px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    z-index: 100;
    mix-blend-mode: normal;
    background: #FFFFFF;
    backdrop-filter: blur(10px);
}

.logo {
    display: flex;
    align-items: center;
}

.logo-img {
    height: 48px;
    width: auto;
    display: block;
}

.nav-link {
    font-family: var(--font-en);
    font-size: 13px;
    font-weight: 400;
    color: var(--text-color);
    letter-spacing: 0.05em;
}

/* Section Common */
.section {
    padding: 200px 0;
    /* Huge vertical whitespace */
    position: relative;
}

/* Hero */
.hero {
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: url('images/concept_hero.png');
    background-size: cover;
    background-position: center;
    z-index: 1;
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(40, 40, 40, 0.4);
    z-index: 2;
}

.hero .container {
    position: relative;
    z-index: 3;
    max-width: 1000px;
}

.hero-jp-sub {
    font-family: var(--font-jp);
    font-size: 1.25rem;
    color: rgba(255, 255, 255, 0.95);
    line-height: 1.8;
    font-weight: 500;
    margin-bottom: 24px;
}

.hero-caption {
    font-family: var(--font-jp);
    font-size: 0.9rem;
    color: rgba(255, 255, 255, 0.8);
    margin-top: 24px;
}

/* Editorial Layouts (Problem / Philosophy) */
.editorial-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 100px;
    align-items: center;
}

.editorial-grid.reverse {
    direction: rtl;
    /* Visual swap */
    grid-template-columns: 1fr 1fr;
}

.editorial-grid.reverse>* {
    direction: ltr;
    /* Text direction reset */
}

.editorial-img {
    width: 100%;
    height: auto;
    object-fit: cover;
    display: block;
    box-shadow: 0 40px 100px rgba(0, 0, 0, 0.08);
    /* Soft, deep shadow */
}

/* Overlap Logic */
.overlap-layout .editorial-img {
    width: 110%;
    margin-left: -5%;
}

.overlap-layout .editorial-text {
    background: var(--bg-color);
    padding: 80px 60px;
    margin-left: -100px;
    /* Pull text over */
    position: relative;
    z-index: 10;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.03);
}

.editorial-grid.reverse.overlap-layout .editorial-text {
    margin-left: 0;
    margin-right: -100px;
}

/* Approach (Architecture) */
.diagram-container {
    display: flex;
    justify-content: center;
    margin-bottom: 140px;
    position: relative;
}

.structure-visual {
    position: relative;
    width: 100%;
    max-width: 500px;
}

.structure-visual-img {
    width: 100%;
    height: auto;
    display: block;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.05);
}

.approach-text {
    text-align: center;
    max-width: 600px;
    margin: 0 auto 100px;
}

/* 3 Core Requirements Grid */
.core-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 60px;
    border-top: 1px solid rgba(0, 0, 0, 0.1);
    padding-top: 60px;
}

.core-item {
    padding-top: 20px;
}

.core-num {
    font-family: var(--font-en);
    font-size: 0.9rem;
    color: var(--text-light);
    display: block;
    margin-bottom: 16px;
}

.core-title {
    font-family: var(--font-en);
    font-weight: 500;
    font-size: 1.1rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 8px;
    color: var(--text-color);
}

.core-jp-sub {
    font-family: var(--font-jp);
    font-weight: 500;
    font-size: 1rem;
    margin-bottom: 24px;
    display: block;
    color: var(--text-color);
}

.core-desc {
    font-size: 0.9rem;
    line-height: 1.9;
    color: var(--text-light);
}

/* Service (Partnership Layers) */
.service-list {
    display: flex;
    flex-direction: column;
    gap: 40px;
    max-width: 900px;
    margin: 0 auto;
}

.service-card {
    display: grid;
    grid-template-columns: 150px 1fr;
    align-items: baseline;
    padding: 40px;
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
    transition: all 0.3s ease;
}

.service-card:hover {
    background: #fff;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.03);
    border-bottom-color: transparent;
    transform: translateX(10px);
}

.layer-tag {
    font-family: var(--font-en);
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--accent-color);
}

.service-content h3 {
    font-family: var(--font-en);
    font-size: 1.5rem;
    color: var(--text-color);
    margin-bottom: 8px;
}

.service-jp {
    font-family: var(--font-jp);
    font-size: 1rem;
    color: var(--text-light);
}

/* Contact */
.contact-layout {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    /* Image larger */
    align-items: center;
}

.contact-img-wrap img {
    width: 100%;
    height: 90vh;
    /* Tall cinematic */
    object-fit: cover;
    filter: grayscale(100%);
    transition: filter 1s ease;
}

.contact-layout:hover .contact-img-wrap img {
    filter: grayscale(0%);
}

.contact-text-wrap {
    background: var(--bg-color);
    padding: 100px 80px;
    margin-left: -150px;
    position: relative;
    z-index: 20;
}

.contact-link {
    display: inline-block;
    margin-top: 40px;
    font-family: var(--font-jp);
    font-size: 1.2rem;
    border-bottom: 1px solid var(--text-color);
    padding-bottom: 8px;
}

/* Animations */
.fade-in-up {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 1.2s ease-out, transform 1.2s ease-out;
}

.fade-in-up.visible {
    opacity: 1;
    transform: translateY(0);
}

.delay-1 {
    transition-delay: 0.2s;
}

.delay-2 {
    transition-delay: 0.3s;
}

.delay-3 {
    transition-delay: 0.4s;
}

/* Responsive */
@media (max-width: 900px) {

    .editorial-grid,
    .editorial-grid.reverse,
    .core-grid,
    .contact-layout,
    .service-card {
        grid-template-columns: 1fr;
        display: flex;
        flex-direction: column;
        gap: 40px;
    }

    .en-title-large {
        font-size: 2.5rem;
    }

    .en-section-title {
        font-size: 2rem;
    }

    .overlap-layout .editorial-text,
    .contact-text-wrap {
        margin: 0;
        padding: 40px 20px;
        background: none;
        box-shadow: none;
    }

    .editorial-img,
    .contact-img-wrap img {
        width: 100%;
        height: auto;
        margin: 0;
    }

    .structure-overlay {
        position: static;
        width: 100%;
        margin-top: 20px;
        right: auto;
        bottom: auto;
        border: none;
    }
}