/* ═══════════════════════════════════════════════
   Responsibility — Shared Light Theme
   ═══════════════════════════════════════════════ */

:root {
    --bg: #F8F7F4;
    --surface: #FFFFFF;
    --surface-2: #F2F0EC;
    --surface-3: #EDEAE5;
    --border: rgba(0,0,0,0.08);
    --border-strong: rgba(0,0,0,0.14);

    --text: #1A1A1A;
    --text-dim: #5C5A57;
    --text-muted: #9A9895;

    --echo-primary: #0D9488;
    --echo-light: #14B8A6;
    --echo-deep: #0F766E;
    --echo-surface: rgba(13,148,136,0.05);
    --echo-border: rgba(13,148,136,0.20);
    --echo-glow: rgba(13,148,136,0.12);

    --quiz-primary: #4A6FA5;
    --quiz-light: #5B82BF;
    --quiz-deep: #3A5A82;
    --quiz-surface: rgba(74,111,165,0.05);
    --quiz-border: rgba(74,111,165,0.20);
    --quiz-glow: rgba(74,111,165,0.12);

    --stargaze-primary: #5B4FA5;
    --stargaze-light: #7A6ED1;
    --stargaze-deep: #47408A;
    --stargaze-surface: rgba(91,79,165,0.05);
    --stargaze-border: rgba(91,79,165,0.20);
    --stargaze-glow: rgba(91,79,165,0.12);

    --shadow-sm: 0 1px 3px rgba(0,0,0,0.04), 0 1px 2px rgba(0,0,0,0.06);
    --shadow-md: 0 4px 16px rgba(0,0,0,0.06), 0 2px 8px rgba(0,0,0,0.04);
    --shadow-lg: 0 12px 40px rgba(0,0,0,0.08), 0 4px 16px rgba(0,0,0,0.04);
    --shadow-xl: 0 20px 60px rgba(0,0,0,0.10), 0 8px 24px rgba(0,0,0,0.04);

    --serif: 'Instrument Serif', Georgia, serif;
    --sans: 'DM Sans', system-ui, -apple-system, sans-serif;
    --mono: 'JetBrains Mono', monospace;

    --max-w: 1200px;
    --radius-sm: 8px;
    --radius-md: 14px;
    --radius-lg: 20px;
    --radius-xl: 28px;
}

/* ── Reset ── */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    scrollbar-width: thin;
    scrollbar-color: var(--text-muted) transparent;
}

body {
    font-family: var(--sans);
    background: var(--bg);
    color: var(--text);
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    line-height: 1.6;
}

::selection {
    background: var(--echo-primary);
    color: #fff;
}

::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--text-muted); border-radius: 3px; }

/* ── Navigation ── */
.nav {
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 100;
    padding: 1.1rem 2.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    backdrop-filter: blur(20px) saturate(1.3);
    -webkit-backdrop-filter: blur(20px) saturate(1.3);
    background: rgba(248,247,244,0.80);
    border-bottom: 1px solid var(--border);
    transition: padding 0.4s ease, background 0.4s ease, box-shadow 0.4s ease;
}

.nav.scrolled {
    padding: 0.7rem 2.5rem;
    background: rgba(248,247,244,0.95);
    box-shadow: var(--shadow-sm);
}

.nav-brand {
    font-family: var(--serif);
    font-size: 1.4rem;
    color: var(--text);
    letter-spacing: -0.02em;
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.nav-brand-dot {
    width: 8px; height: 8px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--echo-primary), var(--quiz-primary));
}

.nav-links {
    display: flex;
    gap: 0.25rem;
    list-style: none;
    align-items: center;
}

.nav-links a {
    font-size: 0.84rem;
    font-weight: 500;
    letter-spacing: 0.02em;
    color: var(--text-dim);
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: var(--radius-sm);
    transition: color 0.3s ease, background 0.3s ease;
}

.nav-links a:hover {
    color: var(--text);
    background: var(--surface-2);
}

.nav-links a.active {
    color: var(--echo-primary);
}

.nav-mobile-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.nav-mobile-toggle span {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--text);
    margin: 5px 0;
    transition: 0.3s;
    border-radius: 2px;
}

/* ── Layout ── */
.container {
    max-width: var(--max-w);
    margin: 0 auto;
}

.section {
    padding: 3rem 2rem;
    position: relative;
}

.section-narrow {
    padding: 4rem 2rem;
}

/* ── Typography ── */
.eyebrow {
    font-family: var(--mono);
    font-size: 0.72rem;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--text-muted);
    margin-bottom: 1rem;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.eyebrow .dot {
    width: 6px; height: 6px;
    border-radius: 50%;
    display: inline-block;
}

.eyebrow.echo { color: var(--echo-primary); }
.eyebrow.echo .dot { background: var(--echo-primary); }
.eyebrow.quiz { color: var(--quiz-primary); }
.eyebrow.quiz .dot { background: var(--quiz-primary); }
.eyebrow.stargaze { color: var(--stargaze-primary); }
.eyebrow.stargaze .dot { background: var(--stargaze-primary); }

h1, h2, h3 {
    font-family: var(--serif);
    letter-spacing: -0.02em;
    line-height: 1.05;
}

h1 { font-size: clamp(2.5rem, 6vw, 4.5rem); }
h2 { font-size: clamp(2rem, 5vw, 3.5rem); }
h3 { font-size: clamp(1.5rem, 3vw, 2rem); }

.italic { font-style: italic; }

.lead {
    font-size: clamp(1rem, 2vw, 1.2rem);
    color: var(--text-dim);
    line-height: 1.75;
    max-width: 580px;
    font-weight: 400;
}

/* ── Buttons ── */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.8rem 1.6rem;
    font-family: var(--sans);
    font-size: 0.88rem;
    font-weight: 600;
    letter-spacing: 0.01em;
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    text-decoration: none;
    transition: transform 0.3s ease, box-shadow 0.3s ease, background 0.3s ease, border-color 0.3s ease, color 0.3s ease;
}

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

.btn-echo {
    background: var(--echo-primary);
    color: #fff;
}
.btn-echo:hover {
    background: var(--echo-deep);
    transform: translateY(-2px);
    box-shadow: 0 8px 24px var(--echo-glow);
}

.btn-quiz {
    background: var(--quiz-primary);
    color: #fff;
}
.btn-quiz:hover {
    background: var(--quiz-deep);
    transform: translateY(-2px);
    box-shadow: 0 8px 24px var(--quiz-glow);
}

.btn-stargaze {
    background: var(--stargaze-primary);
    color: #fff;
}
.btn-stargaze:hover {
    background: var(--stargaze-deep);
    transform: translateY(-2px);
    box-shadow: 0 8px 24px var(--stargaze-glow);
}

.btn-dark {
    background: var(--text);
    color: #fff;
}
.btn-dark:hover {
    background: #333;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-ghost {
    background: transparent;
    color: var(--text-dim);
    border: 1px solid var(--border-strong);
}
.btn-ghost:hover {
    color: var(--text);
    border-color: var(--text);
    background: var(--surface);
}

.btn-lg {
    padding: 1.05rem 2.2rem;
    font-size: 0.95rem;
    border-radius: 10px;
}

.btn svg { flex-shrink: 0; }

/* ── Hero ── */
.hero {
    min-height: auto;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: 9rem 2rem 2rem;
    position: relative;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    inset: 0;
    overflow: hidden;
    z-index: 0;
}

.hero-bg .orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(100px);
    opacity: 0.35;
    animation: orbFloat 14s ease-in-out infinite;
}

.hero-bg .orb-1 {
    width: 480px; height: 480px;
    background: var(--echo-glow);
    top: -8%; left: -6%;
}

.hero-bg .orb-2 {
    width: 420px; height: 420px;
    background: var(--quiz-glow);
    bottom: -8%; right: -6%;
    animation-delay: -5s;
}

@keyframes orbFloat {
    0%, 100% { transform: translate(0,0) scale(1); }
    33% { transform: translate(30px,-20px) scale(1.05); }
    66% { transform: translate(-20px,15px) scale(0.95); }
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 720px;
}

.hero-title {
    font-family: var(--serif);
    font-size: clamp(3rem, 9vw, 7rem);
    line-height: 0.95;
    letter-spacing: -0.03em;
    margin-bottom: 1.5rem;
}

.hero-subtitle {
    font-size: clamp(1.05rem, 2vw, 1.3rem);
    color: var(--text-dim);
    max-width: 520px;
    margin: 0 auto 2.5rem;
    line-height: 1.7;
    font-weight: 400;
}

.hero-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* ── Product Grid (Homepage) ── */
.product-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    max-width: var(--max-w);
    margin: 0 auto;
}

.product-card {
    background: var(--surface);
    border-radius: var(--radius-lg);
    overflow: hidden;
    border: 1px solid var(--border);
    box-shadow: var(--shadow-md);
    transition: transform 0.4s ease, box-shadow 0.4s ease;
    display: flex;
    flex-direction: column;
}

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

.product-card-image {
    aspect-ratio: 16/10;
    overflow: hidden;
    position: relative;
    background: var(--surface-2);
}

.product-card-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.6s ease;
}

.product-card:hover .product-card-image img {
    transform: scale(1.04);
}

.product-card-body {
    padding: 2rem 2rem 1.5rem;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.product-card-tag {
    font-family: var(--mono);
    font-size: 0.68rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    padding: 0.25rem 0.6rem;
    border-radius: 4px;
    display: inline-block;
    margin-bottom: 0.85rem;
    align-self: flex-start;
}

.product-card.echo .product-card-tag {
    background: var(--echo-surface);
    color: var(--echo-primary);
    border: 1px solid var(--echo-border);
}

.product-card.quiz .product-card-tag {
    background: var(--quiz-surface);
    color: var(--quiz-primary);
    border: 1px solid var(--quiz-border);
}

.product-card.stargaze .product-card-tag {
    background: var(--stargaze-surface);
    color: var(--stargaze-primary);
    border: 1px solid var(--stargaze-border);
}

.product-card h3 {
    font-size: 1.8rem;
    margin-bottom: 0.6rem;
}

.product-card-desc {
    font-size: 0.92rem;
    color: var(--text-dim);
    line-height: 1.65;
    margin-bottom: 1.25rem;
}

.product-card-features {
    list-style: none;
    margin-bottom: 1.5rem;
    flex: 1;
}

.product-card-features li {
    font-size: 0.85rem;
    color: var(--text-dim);
    padding: 0.3rem 0;
    display: flex;
    align-items: flex-start;
    gap: 0.5rem;
}

.product-card-features li::before {
    content: '';
    width: 5px; height: 5px;
    border-radius: 50%;
    margin-top: 7px;
    flex-shrink: 0;
}

.product-card.echo .product-card-features li::before { background: var(--echo-primary); }
.product-card.quiz .product-card-features li::before { background: var(--quiz-primary); }
.product-card.stargaze .product-card-features li::before { background: var(--stargaze-primary); }

.product-card-actions {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
}

/* ── Page Hero (Product Pages) ── */
.page-hero {
    padding: 9rem 2rem 4rem;
    position: relative;
    overflow: hidden;
}

.page-hero-inner {
    max-width: var(--max-w);
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.page-hero-text h1 {
    margin-bottom: 1.25rem;
}

.page-hero-text .lead {
    margin-bottom: 2rem;
}

.page-hero-image {
    aspect-ratio: 4/3;
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border);
}

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

.page-hero.echo::before {
    content: '';
    position: absolute;
    top: -20%; right: -10%;
    width: 600px; height: 600px;
    background: var(--echo-glow);
    filter: blur(120px);
    border-radius: 50%;
    opacity: 0.5;
    z-index: 0;
}

.page-hero.quiz::before {
    content: '';
    position: absolute;
    top: -20%; right: -10%;
    width: 600px; height: 600px;
    background: var(--quiz-glow);
    filter: blur(120px);
    border-radius: 50%;
    opacity: 0.5;
    z-index: 0;
}

.page-hero.stargaze::before {
    content: '';
    position: absolute;
    top: -20%; right: -10%;
    width: 600px; height: 600px;
    background: var(--stargaze-glow);
    filter: blur(120px);
    border-radius: 50%;
    opacity: 0.5;
    z-index: 0;
}

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

/* ── Feature Rows ── */
.feature-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
    margin-bottom: 5rem;
}

.feature-row:last-child { margin-bottom: 0; }

.feature-row.reverse .feature-row-image {
    order: -1;
}

.feature-row-image {
    aspect-ratio: 4/3;
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border);
}

.feature-row-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.6s ease;
}

.feature-row-image:hover img {
    transform: scale(1.03);
}

.feature-row-text h3 {
    font-size: 1.6rem;
    margin-bottom: 0.85rem;
}

.feature-row-text p {
    color: var(--text-dim);
    font-size: 0.95rem;
    line-height: 1.75;
}

.feature-row-text .feature-num {
    font-family: var(--mono);
    font-size: 0.72rem;
    letter-spacing: 0.15em;
    color: var(--text-muted);
    display: block;
    margin-bottom: 0.75rem;
}

.echo-text h3 { color: var(--echo-primary); }
.quiz-text h3 { color: var(--quiz-primary); }
.stargaze-text h3 { color: var(--stargaze-primary); }

/* ── Download Section ── */
.download-section {
    text-align: center;
    background: var(--surface);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.download-section .lead {
    margin: 0 auto 2rem;
}

.download-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* ── Privacy Policy ── */
.privacy-section {
    background: var(--surface-2);
    border-top: 1px solid var(--border);
}

.privacy-inner {
    max-width: 720px;
    margin: 0 auto;
}

.privacy-inner h2 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.privacy-meta {
    font-size: 0.82rem;
    color: var(--text-muted);
    margin-bottom: 2.5rem;
}

.privacy-body {
    font-size: 0.92rem;
    line-height: 1.85;
    color: var(--text-dim);
}

.privacy-body h3 {
    font-family: var(--sans);
    font-size: 1rem;
    font-weight: 600;
    color: var(--text);
    margin-top: 2rem;
    margin-bottom: 0.6rem;
    letter-spacing: 0;
}

.privacy-body p { margin-bottom: 0.85rem; }

.privacy-body ul {
    padding-left: 1.5rem;
    margin-bottom: 0.85rem;
}

.privacy-body li {
    margin-bottom: 0.3rem;
}

.privacy-body .developer {
    font-style: italic;
    color: var(--text);
    font-size: 0.98rem;
}

/* ── Support Page ── */
.support-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
    max-width: var(--max-w);
    margin: 0 auto;
}

.support-card {
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: 2.5rem 2rem;
    text-align: center;
    border: 1px solid var(--border);
    box-shadow: var(--shadow-sm);
    transition: transform 0.35s ease, box-shadow 0.35s ease;
}

.support-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.support-card-icon {
    width: 56px; height: 56px;
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.25rem;
}

.support-card-icon.echo { background: var(--echo-surface); color: var(--echo-primary); }
.support-card-icon.quiz { background: var(--quiz-surface); color: var(--quiz-primary); }
.support-card-icon.email { background: var(--surface-3); color: var(--text); }

.support-card h3 {
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
    font-family: var(--sans);
    font-weight: 600;
    letter-spacing: 0;
}

.support-card p {
    font-size: 0.85rem;
    color: var(--text-dim);
    margin-bottom: 1rem;
    line-height: 1.6;
}

.support-card-value {
    font-family: var(--mono);
    font-size: 1.05rem;
    font-weight: 500;
    color: var(--text);
    padding: 0.6rem 1rem;
    background: var(--surface-2);
    border-radius: var(--radius-sm);
    display: inline-block;
    border: 1px solid var(--border);
    cursor: pointer;
    transition: border-color 0.3s ease;
}

.support-card-value:hover {
    border-color: var(--text-muted);
}

/* ── Footer ── */
.footer {
    padding: 2.5rem 2rem 2rem;
    border-top: 1px solid var(--border);
    background: var(--surface);
}

.footer-inner {
    max-width: var(--max-w);
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.footer-brand {
    font-family: var(--serif);
    font-size: 1.1rem;
    color: var(--text-dim);
}

.footer-links {
    display: flex;
    gap: 1.5rem;
    list-style: none;
}

.footer-links a {
    font-size: 0.8rem;
    color: var(--text-muted);
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-links a:hover { color: var(--text-dim); }

.footer-copy {
    font-size: 0.78rem;
    color: var(--text-muted);
}

.footer-beian {
    margin-top: 1rem;
    text-align: center;
}

.footer-beian a {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-beian a:hover { color: var(--text-dim); }

/* ── Animations ── */
.reveal {
    opacity: 0;
    transform: translateY(28px);
    transition: opacity 0.7s ease, transform 0.7s ease;
}

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

@keyframes fadeUp {
    from { opacity: 0; transform: translateY(24px); }
    to { opacity: 1; transform: translateY(0); }
}

.fade-up { animation: fadeUp 0.8s ease forwards; }
.fade-up-delay-1 { opacity: 0; animation: fadeUp 0.8s ease forwards 0.15s; }
.fade-up-delay-2 { opacity: 0; animation: fadeUp 0.8s ease forwards 0.3s; }
.fade-up-delay-3 { opacity: 0; animation: fadeUp 0.8s ease forwards 0.45s; }

/* ── Responsive ── */
@media (max-width: 1080px) {
    .product-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 900px) {
    .product-grid { grid-template-columns: 1fr; }

    .page-hero-inner {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .page-hero-image { order: -1; max-width: 500px; }

    .feature-row {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .feature-row.reverse .feature-row-image { order: 0; }

    .support-grid { grid-template-columns: 1fr; }

    .nav { padding: 1rem 1.5rem; }

    .nav-links { display: none; }

    .nav-mobile-toggle { display: block; }

    .nav-links.open {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0; right: 0;
        background: var(--surface);
        padding: 1rem 1.5rem;
        gap: 0;
        border-bottom: 1px solid var(--border);
        box-shadow: var(--shadow-md);
    }

    .nav-links.open a {
        padding: 0.75rem 0;
        width: 100%;
    }
}

@media (max-width: 600px) {
    .hero { padding: 7rem 1.25rem 1.5rem; }
    .section { padding: 2rem 1.25rem; }
    .page-hero { padding: 7rem 1.25rem 3rem; }
    .product-card-body { padding: 1.5rem 1.25rem 1.25rem; }
    .footer-inner { flex-direction: column; text-align: center; }
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}