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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    background: #f5f5f7;
    color: #1d1d1f;
}

/* ── Header ── */
header {
    background: linear-gradient(135deg, #0057b8 0%, #0078d7 100%);
    color: white;
    padding: 3rem 1rem 2.5rem;
    text-align: center;
}

.logo {
    display: block;
    margin: 0 auto 1rem;
    width: 96px;
    height: 96px;
}

header h1 {
    margin: 0 0 0.4rem;
    font-size: 2.4rem;
    font-weight: 700;
    letter-spacing: -0.5px;
}

.tagline {
    margin: 0 auto 2rem;
    max-width: 540px;
    font-size: 1.05rem;
    opacity: 0.9;
}

/* ── Download Buttons ── */
.download-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    justify-content: center;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.7rem 1.4rem;
    border-radius: 10px;
    font-size: 0.95rem;
    font-weight: 600;
    text-decoration: none;
    transition: opacity 0.15s, transform 0.1s;
    white-space: nowrap;
}

.btn:hover { opacity: 0.88; transform: translateY(-1px); text-decoration: none; }

.btn-chrome {
    background: white;
    color: #1a73e8;
    border: 2px solid rgba(255,255,255,0.4);
}

.btn-appstore {
    background: rgba(255,255,255,0.15);
    color: white;
    border: 2px solid rgba(255,255,255,0.6);
    backdrop-filter: blur(4px);
}

.btn-free {
    display: inline-block;
    font-size: 0.6rem;
    font-weight: 800;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    background: rgba(255,255,255,0.25);
    border: 1px solid rgba(255,255,255,0.5);
    border-radius: 4px;
    padding: 0.1em 0.45em;
    vertical-align: middle;
    line-height: 1.5;
}

.btn-donate {
    background: rgba(255,255,255,0.15);
    color: white;
    border: 2px solid rgba(255,255,255,0.6);
    backdrop-filter: blur(4px);
}

.btn-donate:hover { opacity: 0.88; color: white; }

.btn-icon {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
}

/* ── Main layout ── */
main {
    max-width: 820px;
    margin: 0 auto;
    padding: 2rem 1.25rem 5rem;
}

section {
    background: white;
    border-radius: 14px;
    padding: 1.75rem 1.75rem;
    margin-bottom: 1.5rem;
    box-shadow: 0 1px 4px rgba(0,0,0,0.06);
}

section.intro {
    font-size: 1.05rem;
    color: #444;
    background: none;
    box-shadow: none;
    padding: 1rem 0 0;
}

h2 {
    color: #0057b8;
    font-size: 1.35rem;
    font-weight: 700;
    margin: 0 0 1rem;
}

h3 {
    font-size: 1.05rem;
    font-weight: 600;
    margin: 1.4rem 0 0.3rem;
    color: #1d1d1f;
}

h3:first-of-type { margin-top: 0; }

p { margin: 0 0 0.75rem; }
p:last-child { margin-bottom: 0; }

a { color: #0078d7; text-decoration: none; }
a:hover { text-decoration: underline; }

code {
    font-family: ui-monospace, "SF Mono", Menlo, monospace;
    font-size: 0.875em;
    background: #f0f0f5;
    padding: 0.1em 0.35em;
    border-radius: 4px;
}

/* ── Science stats ── */
.science-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
    margin-bottom: 1.25rem;
}

.science-card {
    background: #f0f5ff;
    border-radius: 10px;
    padding: 1rem;
    text-align: center;
}

.science-stat {
    font-size: 1.8rem;
    font-weight: 700;
    color: #0057b8;
    line-height: 1.1;
}

.science-label {
    font-size: 0.8rem;
    color: #555;
    margin-top: 0.25rem;
}

/* ── Feature list ── */
.feature-list {
    list-style: none;
    padding: 0;
    margin: 0;
    display: grid;
    gap: 0.6rem;
}

.feature-list li {
    padding-left: 1.4rem;
    position: relative;
    font-size: 0.96rem;
}

.feature-list li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: #0078d7;
    font-weight: 700;
}

/* ── Ordered privacy list ── */
.privacy-list {
    padding-left: 1.4rem;
    margin: 0.5rem 0 0;
}

.privacy-list li {
    margin-bottom: 0.4rem;
    font-size: 0.96rem;
}

/* ── Platform chips ── */
.platform-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.platform-chip {
    background: #e8f0fe;
    color: #0057b8;
    border-radius: 20px;
    padding: 0.3rem 0.85rem;
    font-size: 0.88rem;
    font-weight: 500;
}

/* ── Shortcut table ── */
.shortcut-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.95rem;
    margin-top: 1rem;
}

.shortcut-table thead tr {
    background: #f0f5ff;
}

.shortcut-table th {
    text-align: left;
    padding: 0.5rem 0.75rem;
    font-weight: 600;
    color: #0057b8;
    border-bottom: 2px solid #dde7ff;
}

.shortcut-table td {
    padding: 0.45rem 0.75rem;
    border-bottom: 1px solid #f0f0f5;
}

.shortcut-table tr:last-child td { border-bottom: none; }

kbd {
    display: inline-block;
    background: #f0f0f5;
    border: 1px solid #ccc;
    border-bottom-width: 2px;
    border-radius: 5px;
    padding: 0.1em 0.45em;
    font-family: ui-monospace, "SF Mono", Menlo, monospace;
    font-size: 0.85rem;
    color: #1d1d1f;
    min-width: 1.8em;
    text-align: center;
}

/* ── Footer ── */
footer {
    background: #1d1d1f;
    color: #aaa;
    text-align: center;
    padding: 1rem;
    font-size: 0.875rem;
    position: fixed;
    bottom: 0;
    width: 100%;
}

footer a { color: #79b8ff; }
footer a:hover { text-decoration: underline; }

/* ── Responsive ── */
@media (max-width: 600px) {
    header h1 { font-size: 1.8rem; }
    .science-grid { grid-template-columns: 1fr; }
    section { padding: 1.25rem; }
    .shortcut-table { font-size: 0.875rem; }
}