:root {
    --bg-color: #ffffff;
    --text-color: #1d1d1f;
    --text-secondary: #86868b;
    --accent-color: #0071e3;
    --card-bg: #f5f5f7;
    --card-border: rgba(0, 0, 0, 0.05);
    --font-family: "SF Pro JP", "SF Pro Display", "SF Pro Icons", "Helvetica Neue", "Helvetica", "Arial", sans-serif;
    --section-padding: 160px 0;
    --border-radius: 28px;
    --subnav-height: 52px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: var(--font-family);
    line-height: 1.6;
    /* Balanced line height for Japanese */
    font-weight: 400;
    letter-spacing: 0.02em;
    /* Slightly positive tracking for clarity */
    overflow-x: hidden;
    word-break: normal;
    /* Better for mixed English/Japanese */
    overflow-wrap: anywhere;
}

.container {
    max-width: 1024px;
    margin: 0 auto;
    padding: 0 22px;
}

/* --- Local Nav (Apple Signature) --- */

#local-nav {
    position: sticky;
    top: 0;
    width: 100%;
    height: var(--subnav-height);
    background: rgba(255, 255, 255, 0.72);
    backdrop-filter: saturate(180%) blur(20px);
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
    z-index: 9999;
    display: flex;
    align-items: center;
    transition: background-color 0.3s;
}

#local-nav.stuck {
    background: rgba(255, 255, 255, 0.85);
}

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

.product-name {
    font-size: 1.3rem;
    font-weight: 600;
    letter-spacing: -0.01em;
}

.nav-links {
    display: flex;
    gap: 24px;
    align-items: center;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-size: 0.75rem;
    opacity: 0.8;
    transition: opacity 0.2s;
}

.nav-links a:hover {
    opacity: 1;
    color: var(--accent-color);
}

/* --- Typography --- */
h1,
h2,
h3,
h4 {
    font-weight: 700;
    letter-spacing: -0.005em;
}

.headline-xl {
    font-size: clamp(2.5rem, 8vw, 6.5rem);
    /* Reduced min size for mobile */
    line-height: 1.1;
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: 0.2em;
}

.headline-l {
    font-size: clamp(2rem, 6vw, 4.5rem);
    /* Reduced min size for mobile */
    line-height: 1.1;
    font-weight: 700;
    letter-spacing: -0.015em;
}

.headline-m {
    font-size: clamp(1.6rem, 4vw, 2.8rem);
    line-height: 1.2;
    font-weight: 600;
    letter-spacing: -0.01em;
}

.subheadline {
    font-size: clamp(1rem, 2vw, 1.5rem);
    color: var(--text-secondary);
    font-weight: 500;
    line-height: 1.5;
    margin-top: 1.2rem;
    max-width: 42rem;
    /* Better line length for readability */
    margin-left: auto;
    margin-right: auto;
}

.gradient-text {
    background: linear-gradient(135deg, #1d1d1f 20%, #86868b 80%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* --- Animations --- */
.reveal {
    opacity: 0;
    transform: translateY(40px);
    transition: transform 1s cubic-bezier(0.25, 0.1, 0.25, 1), opacity 1s cubic-bezier(0.25, 0.1, 0.25, 1);
}

.reveal.visible {
    opacity: 1;
    transform: translateY(0);
}

/* --- Intro Block (Image Focus) --- */
.intro-block {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 48px;
    text-align: center;
}

.intro-media {
    width: 100%;
    max-width: 640px;
    /* Smaller, focused size per user request */
    margin: 0 auto;
    border-radius: 32px;
    /* Smooth rounded corners */
    overflow: hidden;
    background: var(--card-bg);
    box-shadow: 0 30px 60px rgba(0, 0, 0, 0.08);
    transition: transform 0.6s cubic-bezier(0.2, 0.8, 0.2, 1);
}

.intro-media img {
    width: 100%;
    height: auto;
    display: block;
}

.intro-media:hover {
    transform: scale(1.02);
}

/* --- Hero --- */
#hero {
    height: calc(100vh - var(--subnav-height));
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    background-color: #fff;
    position: relative;
}

.hero-bg-media {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    opacity: 0.1;
    z-index: 0;
}

.hero-bg-media img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.hero-content {
    position: relative;
    z-index: 1;
}

/* --- Sections --- */
.section {
    padding: var(--section-padding);
}

.center-content {
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

/* --- Bento Grid (Dynamic and Complex) --- */
.bento-grid {
    display: grid;
    grid-template-columns: repeat(12, 1fr);
    grid-gap: 24px;
    margin-top: 80px;
}

.bento-item {
    grid-column: span 12;
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 40px;
    position: relative;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    border: 1px solid var(--card-border);
    transition: transform 0.4s cubic-bezier(0.4, 0, 0.25, 1);
}

.bento-item:hover {
    transform: scale(1.01);
}

.bento-item.tall {
    grid-column: span 6;
    height: 320px;
}

.bento-item.wide {
    grid-column: span 12;
}

.bento-item.medium {
    grid-column: span 6;
    height: 360px;
}

.bento-item h3 {
    font-size: 1.8rem;
    margin-bottom: 0.8rem;
}

.bento-item p {
    color: var(--text-secondary);
    font-size: 1rem;
    line-height: 1.5;
    max-width: 100%;
}

.bento-icon {
    font-size: 2.2rem;
    margin-bottom: 20px;
    color: var(--accent-color);
}

/* --- Full Width Media --- */
.full-width-media {
    grid-column: span 12;
    margin-top: 40px;
    border-radius: var(--border-radius);
    overflow: hidden;
    background: #fff;
    border: 1px solid var(--card-border);
    box-shadow: 0 40px 100px rgba(0, 0, 0, 0.06);
}

.full-width-media img {
    width: 100%;
    display: block;
    transition: transform 2.5s cubic-bezier(0.15, 1, 0.15, 1);
}

.full-width-media:hover img {
    transform: scale(1.03);
}

/* --- Formula Display --- */
.formula-display {
    background: var(--card-bg);
    padding: 80px 40px;
    border-radius: var(--border-radius);
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: nowrap;
    /* Forces horizontal layout */
    gap: clamp(10px, 4vw, 40px);
    /* Dynamic gap to prevent wrapping */
    margin: 80px 0;
    border: 1px solid var(--card-border);
    overflow-x: auto;
    /* Fallback for extremely small screens */
}

.expression {
    font-size: 3rem;
    font-weight: 700;
}

.plus,
.equals {
    color: var(--text-secondary);
    font-size: 2.5rem;
    font-weight: 300;
}

/* --- Demo Player --- */
.player-wrapper {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 60px 24px;
    margin-top: 60px;
    border: 1px solid var(--card-border);
}

.player-ui {
    max-width: 500px;
    margin: 0 auto;
}

.stage-labels {
    display: flex;
    justify-content: center;
    gap: 16px;
    flex-wrap: wrap;
}

.label-pill {
    padding: 10px 20px;
    border-radius: 20px;
    background: rgba(0, 0, 0, 0.04);
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 500;
    transition: all 0.2s;
    cursor: pointer;
    white-space: nowrap;
}

.label-pill.active {
    background: #000;
    color: #fff;
}

/* --- Buttons --- */
.apple-btn {
    background: #0071e3;
    color: #fff;
    padding: 12px 22px;
    border-radius: 980px;
    text-decoration: none;
    font-weight: 500;
    font-size: 1.05rem;
    display: inline-block;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.apple-btn:hover {
    background: #0077ed;
    transform: scale(1.05);
}

.apple-btn.secondary {
    background: none;
    color: #0071e3;
}

.apple-btn.secondary::after {
    content: ' >';
    font-weight: 700;
}

.apple-btn.black {
    background: #000;
    color: #fff;
}

/* --- Footer --- */
footer {
    padding: 100px 0;
    background: #f5f5f7;
    color: var(--text-secondary);
}

.footer-content {
    border-top: 1px solid rgba(0, 0, 0, 0.1);
    padding-top: 40px;
    font-size: 0.8rem;
    line-height: 1.6;
}

/* --- Responsive --- */
@media (max-width: 1200px) {
    .nav-links a:not(.apple-btn) {
        display: none;
    }

    .nav-links {
        gap: 16px;
    }

    .product-name {
        font-size: 1.2rem;
        flex-shrink: 0;
    }
}

@media (max-width: 1024px) {

    .bento-item,
    .bento-item.tall,
    .bento-item.medium {
        grid-column: span 12;
        height: auto;
        min-height: 280px;
    }
}

@media (max-width: 768px) {
    :root {
        --section-padding: 60px 0;
    }

    .headline-xl {
        font-size: 2.4rem;
    }

    .headline-l {
        font-size: 2rem;
    }

    .bento-item {
        padding: 32px;
    }

    .bento-item h3 {
        font-size: 1.4rem;
    }

    .formula-display {
        padding: 40px 20px;
        gap: 12px;
    }

    .expression {
        font-size: 1.2rem;
    }

    .plus,
    .equals {
        font-size: 1.2rem;
    }
}

@media (max-width: 480px) {
    .nav-content {
        padding: 0 16px;
    }

    .apple-btn.black {
        padding: 8px 16px;
        font-size: 0.85rem;
    }
}