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

:root {
    --accent: #51B5E0;
    --accent-dark: #3A9AC5;
    --accent-light: rgba(81, 181, 224, 0.1);
    --text: #1d1d1f;
    --text-secondary: #6e6e73;
    --bg: #ffffff;
    --bg-secondary: #f5f5f7;
    --border: #e5e5ea;
    --radius: 16px;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    color: var(--text);
    background: var(--bg);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

a {
    color: var(--accent);
    text-decoration: none;
    transition: color 0.2s;
}

a:hover {
    color: var(--accent-dark);
}

img {
    max-width: 100%;
    display: block;
}

/* ── Layout ── */
.container {
    max-width: 960px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ── Navigation ── */
.nav {
    padding: 16px 0;
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    z-index: 100;
}

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

.nav-brand {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text);
    display: flex;
    align-items: center;
    gap: 10px;
}

.nav-logo {
    width: 32px;
    height: 32px;
    border-radius: 8px;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 28px;
}

.nav-links a {
    font-size: 0.95rem;
    color: var(--text-secondary);
    padding: 8px 0;
}

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

/* ── Hero Section ── */
.hero {
    text-align: center;
    padding: 80px 0 72px;
}

.hero-logo {
    width: 120px;
    height: 120px;
    border-radius: 28px;
    margin: 0 auto 32px;
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.12);
}

.hero h1 {
    font-size: 3.5rem;
    font-weight: 800;
    letter-spacing: -0.03em;
    line-height: 1.1;
    color: var(--text);
    margin-bottom: 20px;
}

.hero h1 span {
    background: linear-gradient(135deg, #51B5E0, #3B82C4);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero .tagline {
    font-size: 1.25rem;
    color: var(--text-secondary);
    max-width: 520px;
    margin: 0 auto 36px;
    line-height: 1.5;
}

.app-store-badge {
    display: inline-block;
    transition: opacity 0.2s;
}

.app-store-badge:hover {
    opacity: 0.8;
}

.app-store-badge img {
    height: 54px;
    display: inline-block;
}

/* ── Features Section ── */
.features {
    padding: 80px 0;
    background: var(--bg-secondary);
}

.section-title {
    text-align: center;
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 12px;
    letter-spacing: -0.02em;
}

.section-subtitle {
    text-align: center;
    color: var(--text-secondary);
    font-size: 1.05rem;
    margin-bottom: 48px;
    max-width: 520px;
    margin-left: auto;
    margin-right: auto;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
}

.feature-card {
    background: var(--bg);
    border-radius: var(--radius);
    padding: 28px 22px;
    text-align: center;
    border: 1px solid var(--border);
    transition: transform 0.2s, box-shadow 0.2s;
}

.feature-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.06);
}

.feature-icon {
    font-size: 2.25rem;
    margin-bottom: 14px;
}

.feature-card h3 {
    font-size: 1.05rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.feature-card p {
    font-size: 0.88rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

/* ── How It Works Section ── */
.how-it-works {
    padding: 80px 0;
}

.steps-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
    margin-top: 48px;
}

.step {
    text-align: center;
}

.step-number {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--accent);
    color: #fff;
    font-size: 1.25rem;
    font-weight: 700;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 16px;
}

.step h3 {
    font-size: 1.15rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.step p {
    font-size: 0.92rem;
    color: var(--text-secondary);
    line-height: 1.5;
    max-width: 260px;
    margin: 0 auto;
}

/* ── CTA Section ── */
.cta {
    padding: 72px 0;
    background: var(--bg-secondary);
    text-align: center;
}

.cta h2 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 12px;
    letter-spacing: -0.02em;
}

.cta p {
    color: var(--text-secondary);
    font-size: 1.05rem;
    margin-bottom: 32px;
}

/* ── Content Pages (Privacy, Support) ── */
.page-content {
    padding: 60px 0 80px;
}

.page-content h1 {
    font-size: 2.25rem;
    font-weight: 700;
    margin-bottom: 8px;
    letter-spacing: -0.02em;
}

.page-content .subtitle {
    color: var(--text-secondary);
    margin-bottom: 40px;
    font-size: 0.95rem;
}

.page-content h2 {
    font-size: 1.35rem;
    font-weight: 600;
    margin-top: 36px;
    margin-bottom: 12px;
    color: var(--text);
}

.page-content h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-top: 24px;
    margin-bottom: 8px;
    color: var(--text);
}

.page-content p,
.page-content li {
    color: var(--text-secondary);
    line-height: 1.75;
    margin-bottom: 12px;
}

.page-content ul {
    padding-left: 20px;
    margin-bottom: 12px;
}

.page-content li {
    margin-bottom: 8px;
}

.back-link {
    display: inline-block;
    margin-top: 40px;
    font-weight: 500;
}

/* ── Support Page ── */
.support-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 20px;
    margin-top: 32px;
}

.support-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px 22px;
    text-align: center;
}

.support-card .icon {
    font-size: 2rem;
    margin-bottom: 12px;
}

.support-card h3 {
    font-size: 1.05rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.support-card p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 0;
}

/* ── FAQ (details/summary) ── */
.faq-section {
    margin-top: 48px;
}

.faq-section h2 {
    margin-bottom: 20px;
}

.faq-item {
    border-bottom: 1px solid var(--border);
}

.faq-item summary {
    padding: 18px 0;
    font-size: 1rem;
    font-weight: 600;
    color: var(--text);
    cursor: pointer;
    list-style: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

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

.faq-item summary::after {
    content: "+";
    font-size: 1.25rem;
    font-weight: 400;
    color: var(--text-secondary);
    transition: transform 0.2s;
    flex-shrink: 0;
    margin-left: 16px;
}

.faq-item[open] summary::after {
    content: "\2212";
}

.faq-item p {
    padding: 0 0 18px;
    color: var(--text-secondary);
    line-height: 1.7;
    font-size: 0.95rem;
    margin-bottom: 0;
}

/* ── Footer ── */
.footer {
    padding: 28px 0;
    border-top: 1px solid var(--border);
    text-align: center;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.footer-links {
    margin-bottom: 12px;
}

.footer-links a {
    color: var(--text-secondary);
    margin: 0 14px;
}

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

/* ── Responsive: Tablet ── */
@media (max-width: 768px) {
    .hero {
        padding: 60px 0 56px;
    }

    .hero h1 {
        font-size: 2.75rem;
    }

    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .steps-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: 20px;
    }
}

/* ── Responsive: Mobile ── */
@media (max-width: 560px) {
    .hero {
        padding: 48px 0 40px;
    }

    .hero-logo {
        width: 96px;
        height: 96px;
        border-radius: 22px;
        margin-bottom: 24px;
    }

    .hero h1 {
        font-size: 2.2rem;
    }

    .hero .tagline {
        font-size: 1.05rem;
    }

    .features,
    .how-it-works,
    .cta {
        padding: 56px 0;
    }

    .section-title {
        font-size: 1.6rem;
    }

    .features-grid {
        grid-template-columns: 1fr;
        gap: 14px;
    }

    .feature-card {
        padding: 22px 18px;
    }

    .steps-grid {
        grid-template-columns: 1fr;
        gap: 28px;
    }

    .nav .container {
        flex-direction: row;
    }

    .nav-links {
        gap: 16px;
    }

    .nav-links a {
        font-size: 0.88rem;
    }

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

    .page-content h1 {
        font-size: 1.8rem;
    }
}