:root {
    --main-green: #66bb6a;
    --deep-green: #2e7d32;
    --soft-green: #e8f5e9;
    --text-main: #2c3e50;
    --white: #ffffff;
}

/* 全体レイアウト：横揺れ防止 */
html,
body {
    overflow-x: hidden;
    width: 100%;
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    scroll-behavior: smooth;
}

*,
*::before,
*::after {
    box-sizing: inherit;
}

body {
    font-family: "Helvetica Neue", Arial, "Hiragino Kaku Gothic ProN", "Hiragino Sans", Meiryo, sans-serif;
    color: var(--text-main);
    background-color: #fcfdfc;
    line-height: 1.7;
}

/* ヘッダー */
header {
    padding: 15px 5%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 1px solid var(--soft-green);
}

.logo {
    font-size: 1.4rem;
    font-weight: 800;
    color: var(--main-green);
    text-decoration: none;
}

/* ヒーローセクション：SEOを意識したh1配置 */
.hero {
    position: relative;
    width: 100%;
    min-height: 70vh;
    /* PC版の高さ */
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    background-image: url('https://images.unsplash.com/photo-1556761223-4c4282c73f77?auto=format&fit=crop&q=80&w=1000');
    background-size: cover;
    background-position: center;
    padding: 40px 20px;
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(to bottom, rgba(232, 245, 233, 0.75), rgba(255, 255, 255, 0.9));
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
    max-width: 800px;
}

.hero h1 {
    font-size: clamp(1.6rem, 5vw, 2.8rem);
    color: var(--deep-green);
    margin-bottom: 20px;
    font-weight: 800;
}

.hero p {
    font-size: clamp(0.95rem, 3vw, 1.15rem);
    margin-bottom: 30px;
    font-weight: 600;
}

/* SP版の画像縦幅調整 */
@media (max-width: 768px) {
    .hero {
        min-height: 45vh;
        /* スマホ版では高さを抑える */
        padding: 30px 15px;
    }

    .hero h1 {
        margin-top: 10px;
    }
}

.btn-main {
    display: inline-block;
    background: linear-gradient(135deg, var(--main-green), var(--deep-green));
    color: white;
    padding: 16px 40px;
    text-decoration: none;
    border-radius: 50px;
    font-size: 1.1rem;
    font-weight: bold;
    box-shadow: 0 8px 20px rgba(76, 175, 80, 0.3);
    transition: 0.3s;
}

.btn-main:hover {
    transform: translateY(-2px);
}

/* コンテンツセクション */
.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 60px 5%;
}

.section-title {
    text-align: center;
    color: var(--deep-green);
    margin-bottom: 40px;
    font-size: 1.8rem;
}

/* SEOキーワードを含めた特徴カード */
.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 25px;
    margin-bottom: 40px;
}

.feature-item {
    background: white;
    padding: 30px;
    border-radius: 20px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    text-align: center;
    border: 1px solid var(--soft-green);
}

.feature-item h2 {
    font-size: 1.3rem;
    color: var(--main-green);
    margin-bottom: 15px;
}

/* 使い方セクション */
#how-to {
    background: var(--soft-green);
    padding: 60px 5%;
    border-radius: 30px;
    margin: 40px 0;
}

.step-list {
    list-style: none;
    padding: 0;
    max-width: 600px;
    margin: 0 auto;
}

.step-list li {
    margin-bottom: 25px;
    padding-left: 55px;
    position: relative;
}

.step-list li::before {
    content: "✓";
    position: absolute;
    left: 0;
    width: 40px;
    height: 40px;
    background: var(--main-green);
    color: white;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-weight: bold;
}

/* フッター */
footer {
    background: var(--deep-green);
    color: white;
    text-align: center;
    padding: 40px 20px;
}