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

:root {
    --purple-700: #3700b3;
    --purple-500: #6200ee;
    --purple-200: #bb86fc;
    --surface: #f5f0ff;
    --on-surface: #1d1b1e;
    --on-surface-variant: #49454e;
    --outline-variant: #cbc4cf;
    --white: #fff;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    color: var(--on-surface);
    background: var(--white);
    line-height: 1.6;
}

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

/* Header */

header {
    background: linear-gradient(135deg, var(--purple-700), var(--purple-500));
    color: var(--white);
    padding: 72px 0 64px;
    text-align: center;
}

header.subpage {
    padding: 32px 0;
    text-align: left;
}

header h1 {
    font-size: 3rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: 8px;
}

.subpage h1 {
    font-size: 2rem;
}

.subtitle {
    font-size: 1.125rem;
    opacity: 0.85;
    margin-bottom: 24px;
}

.back {
    display: inline-block;
    color: var(--white);
    text-decoration: none;
    font-size: 0.875rem;
    opacity: 0.8;
    margin-bottom: 12px;
}

.back:hover {
    opacity: 1;
}

.play-badge img {
    height: 60px;
    filter: drop-shadow(0 2px 8px rgba(0,0,0,0.2));
}

/* Sections */

section {
    padding: 64px 0;
}

section h2 {
    font-size: 1.5rem;
    font-weight: 600;
    letter-spacing: -0.01em;
    margin-bottom: 24px;
    text-align: center;
}

.features {
    background: var(--surface);
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 16px;
}

.card {
    background: var(--white);
    border: 1px solid var(--outline-variant);
    border-radius: 16px;
    padding: 24px;
    transition: box-shadow 0.2s, transform 0.2s;
}

.card:hover {
    box-shadow: 0 4px 20px rgba(98, 0, 238, 0.08);
    transform: translateY(-2px);
}

.card h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.card p {
    font-size: 0.875rem;
    color: var(--on-surface-variant);
    line-height: 1.5;
}

.icon {
    width: 32px;
    height: 32px;
    margin-bottom: 16px;
    background: var(--purple-200);
    border-radius: 8px;
}

/* Screenshot */

.screenshot {
    text-align: center;
}

.screenshot p {
    max-width: 540px;
    margin: 0 auto 32px;
    color: var(--on-surface-variant);
}

.phone-frame {
    max-width: 320px;
    margin: 0 auto;
}

.phone-frame img {
    width: 100%;
    border-radius: 24px;
    box-shadow: 0 8px 40px rgba(0,0,0,0.12);
}

.placeholder-box {
    width: 100%;
    aspect-ratio: 9 / 19;
    background: var(--surface);
    border: 2px dashed var(--outline-variant);
    border-radius: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--on-surface-variant);
    font-size: 0.875rem;
}

/* Open Source */

.open-source {
    background: var(--surface);
    text-align: center;
}

.open-source p {
    margin-bottom: 24px;
    color: var(--on-surface-variant);
}

.button {
    display: inline-block;
    background: var(--purple-500);
    color: var(--white);
    padding: 12px 32px;
    border-radius: 24px;
    text-decoration: none;
    font-weight: 600;
    font-size: 0.9375rem;
    transition: background 0.2s;
}

.button:hover {
    background: var(--purple-700);
}

/* Content page */

.content {
    padding: 48px 0 64px;
}

.prose h2 {
    text-align: left;
    font-size: 1.25rem;
    margin-top: 32px;
    margin-bottom: 12px;
}

.prose p {
    margin-bottom: 16px;
    color: var(--on-surface-variant);
}

.prose a {
    color: var(--purple-500);
}

/* Footer */

footer {
    background: #1d1b1e;
    color: rgba(255,255,255,0.7);
    padding: 24px 0;
    font-size: 0.8125rem;
}

footer .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 8px;
}

footer a {
    color: rgba(255,255,255,0.7);
    text-decoration: none;
}

footer a:hover {
    color: var(--white);
}

nav {
    display: flex;
    gap: 16px;
}

/* Responsive */

@media (max-width: 640px) {
    header { padding: 48px 0 40px; }
    header h1 { font-size: 2rem; }
    .grid { grid-template-columns: 1fr; }
    section { padding: 40px 0; }
}