/* カラー・フォント変数 */
:root {
    --deep-gray: #1a1a1b;    /* 漆黒に近いグレー */
    --slate-gray: #2d2d2f;   /* カード背景 */
    --amber: #d4a373;        /* 琥珀色（アクセント） */
    --muted-gold: #b08d57;   /* くすんだ金 */
    --off-white: #e5e5e5;    /* 読みやすい白 */
    --font-mincho: 'Shippori Mincho B1', serif;
    --font-serif: 'Noto Serif JP', serif;
}

/* 基本設定 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    background-color: var(--deep-gray);
    color: var(--off-white);
    font-family: var(--font-serif);
    line-height: 2;
    font-size: 18px;
}

/* ヘッダー */
header {
    height: 90px;
    background-color: rgba(26, 26, 27, 0.95);
    display: flex;
    align-items: center;
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    border-bottom: 1px solid rgba(212, 163, 115, 0.2);
}

.header-inner {
    max-width: 1400px;
    margin: 0 auto;
    width: 100%;
    padding: 0 50px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-family: var(--font-mincho);
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--amber);
    letter-spacing: 0.15em;
}

nav ul {
    display: flex;
    list-style: none;
    gap: 40px;
}

nav a {
    text-decoration: none;
    color: var(--off-white);
    font-size: 0.9rem;
    letter-spacing: 0.1em;
    transition: 0.3s;
}

nav a:hover {
    color: var(--amber);
}

/* ヒーローセクション：視覚的な重なり */
.hero {
    position: relative;
    height: 90vh;
    display: flex;
    align-items: center;
    overflow: hidden;
}

.hero-image-box {
    position: absolute;
    right: 0;
    top: 0;
    width: 70%;
    height: 100%;
}

.hero-image-box img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.dark-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(to right, var(--deep-gray) 10%, rgba(26, 26, 27, 0.4));
}

.hero-content {
    position: relative;
    z-index: 10;
    max-width: 700px;
    padding-left: 80px;
}

.sub-caption {
    font-family: var(--font-mincho);
    color: var(--amber);
    letter-spacing: 0.4em;
    font-size: 0.8rem;
    display: block;
    margin-bottom: 20px;
}

.hero-content h1 {
    font-family: var(--font-mincho);
    font-size: 3.5rem;
    line-height: 1.3;
    margin-bottom: 30px;
}

.hero-content p {
    font-size: 1.1rem;
    opacity: 0.8;
}

/* 現状セクション：スタックカード */
.problem-area {
    padding: 150px 0;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 40px;
}

.problem-intro {
    text-align: center;
    margin-bottom: 100px;
}

.problem-intro h2 {
    font-family: var(--font-mincho);
    font-size: 2.5rem;
    margin-bottom: 20px;
}

.problem-stack {
    display: flex;
    gap: 30px;
}

.stack-card {
    flex: 1;
    background-color: var(--slate-gray);
    padding: 60px 40px;
    border: 1px solid rgba(212, 163, 115, 0.1);
    transition: transform 0.4s;
}

.stack-card:hover {
    transform: translateY(-15px);
    border-color: var(--amber);
}

.card-head {
    font-family: var(--font-mincho);
    font-size: 2.5rem;
    color: var(--amber);
    margin-bottom: 30px;
    opacity: 0.5;
}

.stack-card h3 {
    font-family: var(--font-mincho);
    font-size: 1.5rem;
    margin-bottom: 20px;
    color: var(--muted-gold);
}

/* 解決セクション：オーバーラップレイアウト */
.solution-area {
    padding-bottom: 150px;
}

.overlap-box {
    display: flex;
    align-items: center;
    position: relative;
}

.overlap-image {
    width: 60%;
    z-index: 1;
}

.overlap-image img {
    width: 100%;
    border-radius: 4px;
    box-shadow: 20px 20px 60px rgba(0,0,0,0.5);
}

.overlap-text {
    width: 50%;
    background-color: var(--slate-gray);
    padding: 80px;
    margin-left: -10%;
    z-index: 2;
    border: 1px solid rgba(212, 163, 115, 0.2);
}

.overlap-text h2 {
    font-family: var(--font-mincho);
    font-size: 2.2rem;
    margin-bottom: 30px;
    line-height: 1.4;
    color: var(--amber);
}

.solution-list {
    margin-top: 30px;
    list-style: none;
}

.solution-list li {
    padding-left: 30px;
    position: relative;
    margin-bottom: 15px;
    font-weight: 500;
}

.solution-list li::before {
    content: '→';
    position: absolute;
    left: 0;
    color: var(--amber);
}

/* フッター */
footer {
    padding: 100px 20px;
    text-align: center;
    background-color: #111;
    border-top: 1px solid var(--slate-gray);
}

.copyright {
    margin-top: 20px;
    font-size: 0.8rem;
    opacity: 0.5;
}

/* レスポンシブ */
@media (max-width: 1000px) {
    .hero {
        height: auto;
        padding-top: 150px;
    }
    .hero-image-box {
        position: relative;
        width: 100%;
        height: 400px;
    }
    .hero-content {
        padding: 50px 40px;
    }
    .problem-stack {
        flex-direction: column;
    }
    .overlap-box {
        flex-direction: column;
    }
    .overlap-image, .overlap-text {
        width: 100%;
        margin-left: 0;
    }
    .overlap-text {
        padding: 40px;
        margin-top: -50px;
    }
}