:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --accent: #3b82f6;
    --text-main: #0f172a;
    --text-muted: #64748b;
    --bg-light: #f8fafc;
    --white: #ffffff;
    --glass: rgba(255, 255, 255, 0.7);
    --shadow: 0 10px 30px rgba(0, 0, 0, 0.05);
}

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

body {
    font-family: 'Noto Sans JP', sans-serif;
    color: var(--text-main);
    background-color: var(--bg-light);
    line-height: 1.6;
    overflow-x: hidden;
}

h1, h2, h3 {
    font-family: 'Outfit', 'Noto Sans JP', sans-serif;
    font-weight: 900;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.text-center { text-align: center; }

/* Header */
header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 80px;
    background: var(--glass);
    backdrop-filter: blur(12px);
    z-index: 1000;
    display: flex;
    align-items: center;
    border-bottom: 1px solid rgba(255, 255, 255, 0.3);
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
}

.logo {
    font-size: 1.5rem;
    font-weight: 900;
    color: var(--primary);
    letter-spacing: -0.02em;
    display: flex;
    align-items: center;
    gap: 12px;
}

.header-icon {
    width: 56px;
    height: 56px;
    object-fit: contain;
    border-radius: 14px;
}

nav {
    display: flex;
    gap: 30px;
    align-items: center;
}

nav a {
    text-decoration: none;
    color: var(--text-main);
    font-weight: 700;
    font-size: 0.95rem;
    transition: color 0.3s;
}

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

/* Hero Section */
.hero {
    padding: 160px 0 100px;
    background: radial-gradient(circle at top right, rgba(59, 130, 246, 0.05), transparent 40%),
                radial-gradient(circle at bottom left, rgba(37, 99, 235, 0.05), transparent 40%);
}

.hero .container {
    display: flex;
    align-items: center;
    gap: 60px;
}

.hero-content {
    flex: 1;
}

.hero-image {
    flex: 1;
    display: flex;
    justify-content: center;
}

.hero-image img {
    max-width: 100%;
    height: auto;
    border-radius: 40px;
    /* 実際には背景なしの透過PNGを想定 */
}

h1 {
    font-size: clamp(1.5rem, 7vw, 3rem); /* さらに一回り小さく調整 */
    line-height: 1.2;
    margin-bottom: 24px;
    word-break: keep-all;
    overflow-wrap: anywhere;
    text-wrap: balance; /* 行の長さを自動でバランス調整 */
    width: 100%;
}

.inline-block {
    display: inline-block;
}

h1 .accent {
    color: var(--primary);
}

.hero-content p {
    font-size: 1.2rem;
    color: var(--text-muted);
    margin-bottom: 40px;
    max-width: 500px;
}

/* Buttons */
.btn {
    display: inline-block;
    background-color: var(--primary);
    color: var(--white);
    text-decoration: none;
    border-radius: 50px;
    font-weight: 800;
    transition: all 0.3s cubic-bezier(0.2, 0.8, 0.2, 1);
    border: none;
    cursor: pointer;
    text-align: center;
}

.btn:hover {
    background-color: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(37, 99, 235, 0.2);
}

.btn:active {
    transform: translateY(0);
}

.btn-small {
    padding: 10px 24px;
    font-size: 0.9rem;
}

.btn-large {
    padding: 20px 48px;
    font-size: 1.1rem;
}

.btn-disabled {
    background-color: var(--text-muted);
    opacity: 0.6;
    cursor: not-allowed;
    pointer-events: none;
}

/* Features */
.features {
    padding: 100px 0;
    background-color: var(--white);
}

.features h2 {
    font-size: 2.5rem;
    margin-bottom: 60px;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 40px;
}

.feature-card {
    background: var(--bg-light);
    padding: 40px;
    border-radius: 30px;
    transition: all 0.3s ease;
    border: 1px solid transparent;
}

.feature-card:hover {
    background: var(--white);
    border-color: rgba(59, 130, 246, 0.1);
    box-shadow: var(--shadow);
    transform: translateY(-10px);
}

.feature-card .icon {
    margin-bottom: 24px;
    color: var(--primary);
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.feature-card .icon svg {
    width: 44px;
    height: 44px;
}

.feature-card h3 {
    font-size: 1.5rem;
    margin-bottom: 16px;
}

.feature-card p {
    color: var(--text-muted);
}

/* How to Use */
.how-to-use {
    padding: 100px 0;
    background-color: var(--bg-light);
}

.how-to-use h2, .faq h2 {
    font-size: 2.5rem;
    margin-bottom: 60px;
}

.step-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.step-card {
    background: var(--white);
    padding: 40px 30px;
    border-radius: 24px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.03);
    position: relative;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid rgba(226, 232, 240, 0.8);
}

.step-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow);
}

.step-badge {
    display: inline-block;
    background: var(--primary);
    color: var(--white);
    font-size: 0.8rem;
    font-weight: 900;
    padding: 6px 14px;
    border-radius: 30px;
    margin-bottom: 18px;
    letter-spacing: 0.05em;
}

.step-card h3 {
    font-size: 1.25rem;
    margin-bottom: 12px;
    line-height: 1.4;
}

.step-card p {
    color: var(--text-muted);
    font-size: 0.95rem;
    line-height: 1.7;
}

/* FAQ Section */
.faq {
    padding: 100px 0;
    background-color: var(--white);
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.faq-item {
    background: var(--bg-light);
    border: 1px solid #e2e8f0;
    border-radius: 16px;
    overflow: hidden;
    transition: all 0.2s ease;
}

.faq-item[open] {
    background: var(--white);
    border-color: #cbd5e1;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.03);
}

.faq-question {
    padding: 22px 24px;
    font-weight: 700;
    font-size: 1.05rem;
    cursor: pointer;
    list-style: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
    user-select: none;
    color: var(--text-main);
}

.faq-question::-webkit-details-marker {
    display: none;
}

.faq-question::after {
    content: '+';
    font-size: 1.5rem;
    font-weight: 400;
    color: var(--primary);
    transition: transform 0.2s ease;
    margin-left: 16px;
    flex-shrink: 0;
}

.faq-item[open] .faq-question::after {
    content: '−';
    transform: rotate(180deg);
}

.faq-answer {
    padding: 0 24px 22px;
    color: var(--text-muted);
    font-size: 0.95rem;
    line-height: 1.8;
    border-top: 1px solid #f1f5f9;
    padding-top: 16px;
}

/* Footer Links */
.footer-nav {
    display: flex;
    justify-content: center;
    gap: 24px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.footer-nav a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: color 0.2s;
}

.footer-nav a:hover {
    color: var(--primary);
    text-decoration: underline;
}

/* Footer */
footer {
    padding: 60px 0;
    background: var(--white);
    border-top: 1px solid #e2e8f0;
    font-size: 0.9rem;
    color: var(--text-muted);
}

/* Animations */
@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInRight {
    from { opacity: 0; transform: translateX(50px); }
    to { opacity: 1; transform: translateX(0); }
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-20px); }
}

.fade-in { animation: fadeInUp 0.8s cubic-bezier(0.2, 0.8, 0.2, 1) forwards; }
.fade-in-right { animation: fadeInRight 1s cubic-bezier(0.2, 0.8, 0.2, 1) forwards; }
.delay-1 { animation-delay: 0.2s; opacity: 0; }
.delay-2 { animation-delay: 0.4s; opacity: 0; }

.floating { animation: float 6s ease-in-out infinite; }

/* Responsive */
@media (max-width: 992px) {
    .hero .container { flex-direction: column; text-align: center; }
    .hero-content p { margin-left: auto; margin-right: auto; }
}

@media (max-width: 768px) {
    nav a:not(.btn) { display: none; }
}

@media (min-width: 769px) {
    .mobile-only { display: none !important; }
}