/* Landing page — mobile-first, same breakpoints as the chat app (768 / 1024).
   Self-contained: the CSP allows no external fonts, so this is the system stack
   throughout, leaning on weight and spacing rather than typefaces for character. */

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

:root {
    --navy: #1B2E48;
    --navy-deep: #132132;
    --green: #5B7D3A;
    --green-hover: #4a672f;
    --ink: #1a1a2e;
    --ink-soft: #55607a;
    --ink-faint: #8b93a7;
    --paper: #ffffff;
    --paper-tint: #f5f6f8;
    --line: #e3e6ec;
    --radius: 12px;
    --radius-lg: 18px;
    --shadow-sm: 0 1px 2px rgba(19, 33, 50, 0.06);
    --shadow-md: 0 4px 20px rgba(19, 33, 50, 0.08);
    --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    --wrap: 1080px;
}

html {
    scroll-behavior: smooth;
}

body.landing {
    font-family: var(--font);
    font-size: 16px;
    line-height: 1.6;
    color: var(--ink);
    background: var(--paper);
    -webkit-text-size-adjust: 100%;
}

@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    * { transition: none !important; }
}

.visually-hidden {
    position: absolute;
    width: 1px; height: 1px;
    padding: 0; margin: -1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
    white-space: nowrap;
    border: 0;
}

/* === NAV === */
.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 14px 20px;
    max-width: var(--wrap);
    margin: 0 auto;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    color: var(--navy);
}

.nav-logo {
    height: 34px;
    width: auto;
    mix-blend-mode: multiply;
}

.nav-name {
    font-size: 17px;
    font-weight: 700;
    letter-spacing: -0.01em;
}

.nav-link {
    font-size: 15px;
    font-weight: 600;
    color: var(--navy);
    text-decoration: none;
    padding: 10px 4px;
    min-height: 44px;
    display: inline-flex;
    align-items: center;
}

.nav-link:hover { color: var(--green); }

/* === HERO === */
.hero {
    max-width: var(--wrap);
    margin: 0 auto;
    padding: 32px 20px 56px;
    text-align: left;
}

.eyebrow {
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--green);
    margin-bottom: 20px;
}

.hero h1 {
    font-size: 34px;
    line-height: 1.15;
    letter-spacing: -0.025em;
    font-weight: 800;
    color: var(--navy);
    margin-bottom: 20px;
}

.hero h1 .accent { color: var(--green); }

.lede {
    font-size: 18px;
    line-height: 1.6;
    color: var(--ink-soft);
    max-width: 620px;
    margin-bottom: 32px;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-bottom: 16px;
}

.hero-note {
    font-size: 14px;
    color: var(--ink-faint);
}

/* === BUTTONS === */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 13px 26px;
    border: 1px solid transparent;
    border-radius: var(--radius);
    font-family: inherit;
    font-size: 16px;
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: background-color 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}

.btn-primary {
    background: var(--navy);
    color: #fff;
}
.btn-primary:hover { background: var(--navy-deep); }

.btn-secondary {
    background: var(--green);
    color: #fff;
}
.btn-secondary:hover { background: var(--green-hover); }

.btn-ghost {
    background: transparent;
    color: var(--navy);
    border-color: var(--line);
}
.btn-ghost:hover { border-color: var(--navy); }

.btn-block { width: 100%; }

.btn:disabled { opacity: 0.55; cursor: not-allowed; }

/* === SECTIONS === */
.section {
    max-width: var(--wrap);
    margin: 0 auto;
    padding: 56px 20px;
}

.section-alt {
    max-width: none;
    background: var(--paper-tint);
    border-top: 1px solid var(--line);
    border-bottom: 1px solid var(--line);
}

.section-alt > * {
    max-width: var(--wrap);
    margin-left: auto;
    margin-right: auto;
}

.section-title {
    font-size: 26px;
    line-height: 1.25;
    letter-spacing: -0.02em;
    font-weight: 800;
    color: var(--navy);
    margin-bottom: 14px;
}

.section-lede {
    font-size: 17px;
    color: var(--ink-soft);
    max-width: 640px;
    margin-bottom: 36px;
}

/* === PROBLEM CARDS === */
.cards {
    display: grid;
    grid-template-columns: 1fr;
    gap: 16px;
}

.card {
    background: var(--paper);
    border: 1px solid var(--line);
    border-radius: var(--radius-lg);
    padding: 24px;
    box-shadow: var(--shadow-sm);
}

.card-num {
    display: inline-block;
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 0.1em;
    color: var(--green);
    margin-bottom: 10px;
}

.card h3 {
    font-size: 18px;
    font-weight: 700;
    color: var(--navy);
    margin-bottom: 8px;
}

.card p {
    font-size: 15.5px;
    color: var(--ink-soft);
}

/* === STEPS === */
.steps {
    list-style: none;
    display: grid;
    grid-template-columns: 1fr;
    gap: 24px;
}

.step-num {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 34px;
    height: 34px;
    border-radius: 50%;
    background: var(--navy);
    color: #fff;
    font-size: 15px;
    font-weight: 700;
    margin-bottom: 12px;
}

.step h3 {
    font-size: 18px;
    font-weight: 700;
    color: var(--navy);
    margin-bottom: 6px;
}

.step p {
    font-size: 15.5px;
    color: var(--ink-soft);
}

/* === DEMO === */
.demo {
    border: 1px solid var(--line);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-md);
}

.demo-q {
    background: var(--navy);
    color: #fff;
    padding: 20px 22px;
    font-size: 16px;
    font-weight: 500;
}

.demo-a {
    background: var(--paper);
    padding: 22px;
    font-size: 15.5px;
    color: var(--ink);
}

.demo-a p { margin-bottom: 14px; }
.demo-a strong { color: var(--navy); }

.demo-note {
    padding-top: 14px;
    border-top: 1px solid var(--line);
    color: var(--ink-soft);
}

.demo-sources {
    font-size: 13px;
    color: var(--ink-faint);
    padding-top: 12px;
    border-top: 1px dashed var(--line);
}

.demo-caption {
    margin-top: 12px;
    font-size: 13.5px;
    color: var(--ink-faint);
}

/* === DATA SOURCES === */
.sources {
    list-style: none;
    display: grid;
    grid-template-columns: 1fr;
    gap: 12px;
}

.sources li {
    display: flex;
    flex-direction: column;
    gap: 2px;
    background: var(--paper);
    border: 1px solid var(--line);
    border-left: 3px solid var(--green);
    border-radius: var(--radius);
    padding: 14px 16px;
}

.sources strong {
    font-size: 15px;
    color: var(--navy);
}

.sources span {
    font-size: 14px;
    color: var(--ink-soft);
}

/* === ACCESS === */
.access-forms {
    display: grid;
    grid-template-columns: 1fr;
    gap: 16px;
}

.access-card {
    background: var(--paper);
    border: 1px solid var(--line);
    border-radius: var(--radius-lg);
    padding: 26px;
    box-shadow: var(--shadow-sm);
}

.access-card h3 {
    font-size: 19px;
    font-weight: 700;
    color: var(--navy);
    margin-bottom: 6px;
}

.access-copy {
    font-size: 15px;
    color: var(--ink-soft);
    margin-bottom: 18px;
}

.access-input {
    width: 100%;
    min-height: 48px;
    padding: 12px 14px;
    margin-bottom: 12px;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    font-family: inherit;
    font-size: 16px; /* prevents iOS zoom */
    color: var(--ink);
    background: var(--paper);
}

.access-input:focus {
    outline: none;
    border-color: var(--navy);
    box-shadow: 0 0 0 3px rgba(27, 46, 72, 0.12);
}

.access-input[aria-invalid="true"] {
    border-color: #b3261e;
}

.form-msg {
    margin-top: 12px;
    font-size: 14.5px;
    line-height: 1.5;
    color: var(--ink-soft);
    min-height: 1px;
}

.form-msg.is-success {
    color: var(--green);
    font-weight: 600;
}

.form-msg.is-error {
    color: #b3261e;
}

.access-note {
    margin-top: 20px;
    padding: 14px 16px;
    border-radius: var(--radius);
    background: #fff6e6;
    border: 1px solid #f0d9a8;
    font-size: 15px;
    color: #6b4c12;
}

/* === FOOTER === */
.footer {
    border-top: 1px solid var(--line);
    padding: 28px 20px 40px;
    max-width: var(--wrap);
    margin: 0 auto;
}

.footer p { font-size: 14.5px; color: var(--ink-soft); }
.footer strong { color: var(--navy); }

.footer-scope {
    margin-top: 6px;
    font-size: 13.5px;
    color: var(--ink-faint);
}

/* === TABLET === */
@media (min-width: 768px) {
    .nav { padding: 18px 32px; }
    .hero { padding: 48px 32px 72px; }
    .hero h1 { font-size: 46px; }
    .lede { font-size: 19px; }
    .section { padding: 72px 32px; }
    .section-title { font-size: 32px; }
    .cards { grid-template-columns: repeat(2, 1fr); gap: 20px; }
    .steps { grid-template-columns: repeat(3, 1fr); gap: 28px; }
    .sources { grid-template-columns: repeat(2, 1fr); }
    .access-forms { grid-template-columns: repeat(2, 1fr); gap: 20px; }
    .demo-q, .demo-a { padding: 26px 30px; }
    .footer { padding: 32px 32px 48px; }
}

/* === DESKTOP === */
@media (min-width: 1024px) {
    .hero { padding: 64px 32px 88px; }
    .hero h1 { font-size: 54px; }
    .section { padding: 88px 32px; }
    .sources { grid-template-columns: repeat(3, 1fr); }
}