/* =====================================================================
   Carbon Footprint Quiz marketing site — Claude design language
   Warm cream by day, warm charcoal by night, single coral accent,
   serif display + system sans, hairline borders, generous whitespace.
   ===================================================================== */

:root {
    /* --- Light theme tokens -------------------------------------------- */
    --bg:           #F4F1EA;
    --bg-deep:      #EAE5D9;
    --surface:      #FDFBF6;
    --surface-alt:  #F1ECE0;
    --surface-hi:   #FFFFFF;
    --ink:          #21201C;
    --ink-soft:     #46443E;
    --ink-mute:     #76726A;
    --ink-faint:    #A39E92;
    --rule:         #DED7C7;
    --rule-soft:    #E9E3D5;
    --coral:        #D97757;
    --coral-deep:   #BC5A3F;
    --coral-soft:   #F6E4DC;
    --gold:         #CB9A3A;
    --success:      #5E7F3F;
    --slate:        #4A6FA5;
    --plum:         #8A5A8F;
    --teal:         #3F8079;

    --shadow-sm: 0 1px 2px rgba(33,32,28,.04), 0 4px 12px rgba(33,32,28,.05);
    --shadow-md: 0 8px 24px rgba(33,32,28,.07);
    --shadow-lg: 0 24px 60px rgba(33,32,28,.10);

    --radius-sm: 10px;
    --radius-md: 16px;
    --radius-lg: 22px;

    --font-serif: ui-serif, "New York", Georgia, "Times New Roman", serif;
    --font-sans:  -apple-system, BlinkMacSystemFont, "SF Pro Text", "Inter",
                  system-ui, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg:          #1E1D1B;
        --bg-deep:     #171614;
        --surface:     #2A2926;
        --surface-alt: #322F2B;
        --surface-hi:  #3A3733;
        --ink:         #F5F1E6;
        --ink-soft:    #C9C4B6;
        --ink-mute:    #95907F;
        --ink-faint:   #6B675C;
        --rule:        #413E38;
        --rule-soft:   #37342F;
        --coral:       #E2906F;
        --coral-deep:  #CB7152;
        --coral-soft:  #40342D;
        --gold:        #EFC368;
        --success:     #9BBE6E;
        --slate:       #86A6D6;
        --plum:        #BE93C2;
        --teal:        #6FB8AE;
        --shadow-sm: 0 1px 2px rgba(0,0,0,.30), 0 4px 12px rgba(0,0,0,.35);
        --shadow-md: 0 8px 24px rgba(0,0,0,.40);
        --shadow-lg: 0 24px 60px rgba(0,0,0,.50);
    }
}

/* --- Reset --------------------------------------------------------------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
    background: var(--bg);
    color: var(--ink);
    font-family: var(--font-sans);
    font-size: 17px;
    line-height: 1.55;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

[hidden] { display: none !important; }
a { color: var(--coral-deep); text-decoration: none; }
a:hover { color: var(--coral); text-decoration: underline; text-underline-offset: 3px; }
img, svg { display: block; max-width: 100%; }

[dir="rtl"] { letter-spacing: 0; }

/* --- Skip link ----------------------------------------------------------- */
.skip-link {
    position: absolute; left: -9999px;
    background: var(--coral); color: #fff; padding: 8px 14px;
    border-radius: 8px; font-weight: 700;
}
.skip-link:focus { left: 14px; top: 14px; }

/* --- Layout primitives --------------------------------------------------- */
.container { max-width: 1120px; margin: 0 auto; padding: 0 24px; }
@media (max-width: 640px) { .container { padding: 0 18px; } }

section { padding: 96px 0; }
@media (max-width: 768px) { section { padding: 64px 0; } }

.eyebrow {
    display: inline-block;
    font-size: 13px; font-weight: 700;
    letter-spacing: .12em; text-transform: uppercase;
    color: var(--coral);
    margin-bottom: 18px;
}
.title {
    font-family: var(--font-serif);
    font-weight: 600;
    color: var(--ink);
    letter-spacing: -.01em;
    max-width: 800px;
    line-height: 1.15;
}
h1.title { font-size: clamp(34px, 5vw, 60px); }
h2.title { font-size: clamp(28px, 3.5vw, 44px); }
h3.title { font-size: clamp(22px, 2.4vw, 30px); }

.subtitle {
    margin-top: 18px;
    font-size: 18px;
    color: var(--ink-soft);
    max-width: 720px;
    line-height: 1.55;
}

/* --- Buttons ------------------------------------------------------------- */
.btn {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 14px 24px;
    border-radius: 999px;
    font-weight: 600;
    font-size: 16px;
    font-family: var(--font-sans);
    cursor: pointer;
    border: 0;
    transition: transform .15s ease, opacity .15s ease, box-shadow .15s ease;
    white-space: nowrap;
}
.btn:hover { text-decoration: none; }
.btn:active { transform: scale(.98); }
.btn-primary {
    background: linear-gradient(135deg, var(--coral), var(--coral-deep));
    color: #fff;
    box-shadow: 0 6px 16px rgba(217,119,87,.35);
}
.btn-primary:hover {
    box-shadow: 0 10px 24px rgba(217,119,87,.45);
    color: #fff;
}
.btn-secondary {
    background: var(--surface);
    color: var(--ink);
    border: 1px solid var(--rule);
}
.btn-secondary:hover { background: var(--surface-hi); }
.btn-link {
    background: transparent; color: var(--coral-deep); padding: 0;
}

/* --- Top nav ------------------------------------------------------------- */
.nav {
    position: sticky; top: 0; z-index: 50;
    backdrop-filter: blur(18px);
    -webkit-backdrop-filter: blur(18px);
    background: color-mix(in srgb, var(--bg) 85%, transparent);
    border-bottom: 1px solid color-mix(in srgb, var(--rule) 60%, transparent);
}
.nav-inner {
    display: flex; align-items: center; gap: 24px;
    padding: 14px 0;
}
.brand {
    display: flex; align-items: center; gap: 10px;
    color: var(--ink);
    font-family: var(--font-serif);
    font-weight: 600;
    font-size: 19px;
}
.brand:hover { color: var(--ink); text-decoration: none; }
.brand-mark {
    width: 32px; height: 32px;
    background: linear-gradient(135deg, var(--coral), var(--coral-deep));
    border-radius: 8px;
    display: grid; place-items: center;
    color: #fff;
    box-shadow: 0 4px 10px rgba(217,119,87,.30);
}
.nav-links {
    display: flex; gap: 24px; align-items: center;
    margin-left: auto;
    font-size: 14px;
    font-weight: 500;
}
.nav-links a { color: var(--ink-soft); }
.nav-links a:hover { color: var(--ink); text-decoration: none; }
.nav-cta {
    background: var(--ink); color: var(--bg);
    padding: 9px 16px; border-radius: 999px;
    font-weight: 600;
}
.nav-cta:hover { color: var(--bg); }
@media (max-width: 720px) {
    .nav-links { gap: 14px; font-size: 13px; }
    .nav-links a:not(.nav-cta) { display: none; }
}

/* --- Hero ---------------------------------------------------------------- */
.hero { padding-top: 80px; padding-bottom: 64px; position: relative; overflow: hidden; }
.hero::before {
    content: "";
    position: absolute; inset: 0;
    background:
        radial-gradient(60% 50% at 20% 10%, color-mix(in srgb, var(--coral) 16%, transparent), transparent 60%),
        radial-gradient(40% 35% at 90% 20%, color-mix(in srgb, var(--slate) 10%, transparent), transparent 60%);
    pointer-events: none;
}
.hero-grid {
    display: grid;
    grid-template-columns: 1.1fr 1fr;
    gap: 56px;
    align-items: center;
    position: relative;
}
@media (max-width: 900px) {
    .hero-grid { grid-template-columns: 1fr; gap: 32px; }
}

.hero-cta { display: flex; gap: 12px; margin-top: 28px; flex-wrap: wrap; }

.hero-stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 14px;
    margin-top: 36px;
}
@media (max-width: 600px) { .hero-stats { grid-template-columns: repeat(2, 1fr); } }
.stat {
    padding: 14px 16px;
    background: var(--surface);
    border: 1px solid var(--rule);
    border-radius: var(--radius-md);
}
.stat-value {
    font-family: var(--font-serif);
    font-size: 28px;
    font-weight: 600;
    color: var(--ink);
    line-height: 1;
}
.stat-label {
    margin-top: 6px;
    font-size: 12px;
    color: var(--ink-mute);
    line-height: 1.35;
}

/* Phone mock-up */
.phone-frame {
    position: relative;
    width: 100%; max-width: 360px;
    margin: 0 auto;
    aspect-ratio: 9 / 19.5;
    background: var(--ink);
    border-radius: 44px;
    padding: 12px;
    box-shadow: var(--shadow-lg), inset 0 0 0 2px rgba(255,255,255,.05);
}
.phone-screen {
    width: 100%; height: 100%;
    background: linear-gradient(180deg, var(--bg), var(--bg-deep));
    border-radius: 32px;
    overflow: hidden;
    position: relative;
    padding: 28px 18px 18px;
    display: flex; flex-direction: column;
}
.phone-notch {
    position: absolute; top: 8px; left: 50%; transform: translateX(-50%);
    width: 90px; height: 24px;
    background: var(--ink);
    border-radius: 18px;
}
.phone-content {
    margin-top: 10px;
    display: flex; flex-direction: column; gap: 14px;
    flex: 1;
}

.q-card {
    background: var(--surface-alt);
    border: 1px solid var(--rule);
    border-radius: var(--radius-md);
    padding: 14px;
}
.q-meta { display: flex; align-items: center; justify-content: space-between; }
.q-tag {
    display: inline-flex; align-items: center; gap: 4px;
    background: var(--coral-soft);
    color: var(--coral-deep);
    font-size: 11px; font-weight: 700;
    padding: 4px 9px; border-radius: 999px;
}
.q-timer {
    display: inline-flex; align-items: center; gap: 4px;
    border: 1px solid var(--rule);
    background: var(--surface);
    font-size: 11px; font-weight: 600;
    padding: 4px 9px; border-radius: 999px;
    color: var(--ink-soft);
}
.q-question {
    font-family: var(--font-serif);
    font-weight: 600;
    font-size: 15px;
    line-height: 1.3;
    color: var(--ink);
    margin: 10px 0 4px;
}
.q-answers { display: flex; flex-direction: column; gap: 7px; }
.q-answer {
    display: flex; align-items: center; gap: 10px;
    padding: 9px 10px;
    background: var(--surface);
    border: 1px solid var(--rule);
    border-radius: 12px;
    font-size: 12px;
    color: var(--ink);
}
.q-letter {
    width: 22px; height: 22px;
    background: var(--coral-soft);
    color: var(--coral-deep);
    border-radius: 50%;
    display: grid; place-items: center;
    font-weight: 700;
    font-size: 11px;
}
.q-card-cta {
    margin-top: 4px;
    padding: 11px;
    text-align: center;
    background: linear-gradient(135deg, var(--coral), var(--coral-deep));
    color: #fff;
    border-radius: 12px;
    font-weight: 700;
    font-size: 13px;
}

/* --- Why-section --------------------------------------------------------- */
.why-section { background: var(--bg-deep); }
.why-grid {
    display: grid; grid-template-columns: 1.4fr 1fr; gap: 56px;
    align-items: start;
}
@media (max-width: 900px) { .why-grid { grid-template-columns: 1fr; } }
.why-source {
    margin-top: 18px;
    font-size: 13px;
    color: var(--ink-faint);
    line-height: 1.55;
}

.pillars {
    display: flex; flex-direction: column; gap: 18px;
}
.pillar {
    padding: 22px 24px;
    background: var(--surface);
    border: 1px solid var(--rule);
    border-radius: var(--radius-md);
}
.pillar-title {
    font-family: var(--font-serif);
    font-weight: 600;
    font-size: 19px;
    color: var(--ink);
    margin-bottom: 6px;
}
.pillar-body { font-size: 15px; color: var(--ink-soft); line-height: 1.55; }

/* --- Features ------------------------------------------------------------ */
.features-grid {
    margin-top: 56px;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 18px;
}
@media (max-width: 900px) { .features-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 600px) { .features-grid { grid-template-columns: 1fr; } }

.feature {
    padding: 24px;
    background: var(--surface);
    border: 1px solid var(--rule);
    border-radius: var(--radius-md);
    transition: transform .25s ease, box-shadow .25s ease;
}
.feature:hover { transform: translateY(-2px); box-shadow: var(--shadow-md); }
.feature-icon {
    width: 44px; height: 44px;
    border-radius: 14px;
    background: var(--coral-soft);
    color: var(--coral);
    display: grid; place-items: center;
    margin-bottom: 14px;
}
.feature-icon svg { width: 22px; height: 22px; }
.feature-title {
    font-family: var(--font-serif);
    font-size: 18px; font-weight: 600;
    color: var(--ink); margin-bottom: 6px;
}
.feature-body { font-size: 14px; color: var(--ink-soft); line-height: 1.55; }

/* --- Science section ----------------------------------------------------- */
.science {
    background:
        linear-gradient(180deg, var(--bg) 0%, var(--bg-deep) 100%);
}
.science-grid {
    margin-top: 56px;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 18px;
}
@media (max-width: 800px) { .science-grid { grid-template-columns: 1fr; } }

.source {
    padding: 26px;
    background: var(--surface);
    border: 1px solid var(--rule);
    border-radius: var(--radius-md);
    display: flex; flex-direction: column; gap: 10px;
}
.source-head { display: flex; align-items: baseline; justify-content: space-between; gap: 8px; flex-wrap: wrap; }
.source-org {
    font-family: var(--font-serif);
    font-weight: 600;
    font-size: 22px;
    color: var(--ink);
}
.source-tag {
    font-size: 12px; font-weight: 600;
    color: var(--coral);
    text-transform: uppercase;
    letter-spacing: .08em;
}
.source-body { font-size: 14.5px; color: var(--ink-soft); line-height: 1.55; }
.source-citation {
    margin-top: 6px;
    font-size: 12px;
    color: var(--ink-mute);
    border-top: 1px solid var(--rule-soft);
    padding-top: 10px;
    font-style: italic;
    line-height: 1.5;
}
.science-full-list {
    margin-top: 30px;
    text-align: center;
    color: var(--ink-mute);
    font-size: 14px;
}

/* --- Numbers ------------------------------------------------------------- */
.numbers { background: var(--bg-deep); }
.numbers-grid {
    margin-top: 56px;
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 18px;
}
@media (max-width: 900px) { .numbers-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 540px) { .numbers-grid { grid-template-columns: 1fr; } }
.number {
    padding: 28px 22px;
    background: var(--surface);
    border: 1px solid var(--rule);
    border-radius: var(--radius-md);
    display: flex; flex-direction: column; gap: 8px;
}
.number-value {
    font-family: var(--font-serif);
    font-size: clamp(36px, 4vw, 50px);
    font-weight: 600;
    color: var(--coral);
    line-height: 1;
    letter-spacing: -.02em;
}
.number-label { font-size: 14px; color: var(--ink-soft); line-height: 1.5; }
.number-source { font-size: 12px; color: var(--ink-faint); margin-top: auto; }

/* --- How it works -------------------------------------------------------- */
.steps {
    margin-top: 56px;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 22px;
}
@media (max-width: 800px) { .steps { grid-template-columns: 1fr; } }
.step {
    padding: 28px;
    background: var(--surface);
    border: 1px solid var(--rule);
    border-radius: var(--radius-md);
    position: relative;
}
.step-num {
    width: 36px; height: 36px;
    border-radius: 50%;
    background: var(--coral-soft);
    color: var(--coral-deep);
    font-weight: 800; font-size: 16px;
    display: grid; place-items: center;
    margin-bottom: 14px;
    font-family: var(--font-serif);
}
.step-title {
    font-family: var(--font-serif);
    font-weight: 600;
    font-size: 20px;
    color: var(--ink);
    margin-bottom: 6px;
}
.step-body { font-size: 14.5px; color: var(--ink-soft); line-height: 1.55; }

/* --- Testimonials -------------------------------------------------------- */
.tests-grid {
    margin-top: 56px;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 18px;
}
@media (max-width: 900px) { .tests-grid { grid-template-columns: 1fr; } }
.testimonial {
    padding: 28px;
    background: var(--surface);
    border: 1px solid var(--rule);
    border-radius: var(--radius-md);
    display: flex; flex-direction: column; gap: 14px;
}
.testimonial-stars { display: flex; gap: 3px; color: var(--gold); }
.testimonial-stars svg { width: 16px; height: 16px; }
.testimonial-quote {
    font-family: var(--font-serif);
    font-size: 18px;
    color: var(--ink);
    line-height: 1.5;
    font-style: italic;
}
.testimonial-author {
    margin-top: auto;
    font-size: 14px;
    color: var(--ink-soft);
}
.testimonial-name { font-weight: 700; color: var(--ink); }

/* --- Languages ----------------------------------------------------------- */
.lang-section { background: var(--bg-deep); }
.lang-grid {
    margin-top: 36px;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(170px, 1fr));
    gap: 8px;
}
.lang-chip {
    display: flex; align-items: center; gap: 8px;
    padding: 10px 12px;
    background: var(--surface);
    border: 1px solid var(--rule);
    border-radius: 12px;
    font-size: 13px;
    line-height: 1.2;
}
.lang-flag { font-size: 18px; line-height: 1; }
.lang-name { font-weight: 600; color: var(--ink); }
.lang-native { color: var(--ink-mute); font-size: 12px; }

/* --- FAQ ----------------------------------------------------------------- */
.faq-grid {
    margin-top: 36px;
    display: grid; gap: 12px;
    max-width: 880px;
}
.faq-item {
    background: var(--surface);
    border: 1px solid var(--rule);
    border-radius: var(--radius-md);
    padding: 0;
    overflow: hidden;
}
.faq-q {
    width: 100%; text-align: left;
    background: none; border: none; cursor: pointer;
    padding: 20px 24px;
    font-size: 17px;
    font-weight: 600;
    color: var(--ink);
    font-family: var(--font-sans);
    display: flex; align-items: center; justify-content: space-between; gap: 14px;
}
.faq-q::after {
    content: "+";
    color: var(--coral);
    font-size: 24px; line-height: 1;
    transition: transform .2s;
}
.faq-item[open] .faq-q::after { transform: rotate(45deg); }
.faq-a {
    padding: 0 24px 22px;
    font-size: 15.5px;
    color: var(--ink-soft);
    line-height: 1.65;
}

/* --- CTA ----------------------------------------------------------------- */
.cta {
    background: linear-gradient(140deg, var(--coral) 0%, var(--coral-deep) 100%);
    color: #fff;
    text-align: center;
    padding: 96px 24px;
    border-radius: var(--radius-lg);
    margin: 64px 24px;
    box-shadow: var(--shadow-lg);
    position: relative;
    overflow: hidden;
}
.cta::before {
    content: "";
    position: absolute; inset: 0;
    background:
        radial-gradient(40% 40% at 20% 30%, rgba(255,255,255,.18), transparent 60%),
        radial-gradient(30% 30% at 80% 70%, rgba(255,255,255,.10), transparent 60%);
    pointer-events: none;
}
.cta > * { position: relative; }
.cta .title { color: #fff; max-width: 740px; margin: 0 auto; }
.cta .subtitle { color: rgba(255,255,255,.85); margin-left: auto; margin-right: auto; }
.cta .btn-primary {
    background: #fff;
    color: var(--coral-deep);
    margin-top: 32px;
    box-shadow: 0 10px 30px rgba(0,0,0,.20);
}
.cta .btn-primary:hover { color: var(--coral-deep); }
.cta-qr { margin-top: 20px; color: rgba(255,255,255,.75); font-size: 14px; }

/* --- Footer -------------------------------------------------------------- */
.footer {
    padding: 56px 24px 80px;
    background: var(--bg-deep);
    border-top: 1px solid var(--rule);
}
.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 36px;
    align-items: start;
}
@media (max-width: 720px) { .footer-grid { grid-template-columns: 1fr; gap: 24px; } }
.footer-brand { display: flex; align-items: center; gap: 10px; }
.footer-tag {
    margin-top: 12px;
    font-size: 14px;
    color: var(--ink-mute);
    max-width: 320px;
}
.footer h4 {
    font-size: 12px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .1em;
    color: var(--ink-mute);
    margin-bottom: 12px;
}
.footer ul { list-style: none; display: flex; flex-direction: column; gap: 8px; }
.footer ul a {
    font-size: 14px;
    color: var(--ink-soft);
}
.footer ul a:hover { color: var(--ink); text-decoration: none; }

.lang-switcher select {
    width: 100%;
    background: var(--surface);
    color: var(--ink);
    border: 1px solid var(--rule);
    border-radius: 10px;
    padding: 10px 12px;
    font-family: var(--font-sans);
    font-size: 14px;
    cursor: pointer;
}

.footer-bottom {
    margin-top: 48px;
    padding-top: 24px;
    border-top: 1px solid var(--rule);
    color: var(--ink-mute);
    font-size: 13px;
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 12px;
}

/* --- Reveal on scroll ---------------------------------------------------- */
@media (prefers-reduced-motion: no-preference) {
    .reveal {
        opacity: 0;
        transform: translateY(16px);
        transition: opacity .6s ease, transform .6s ease;
    }
    .reveal.is-visible { opacity: 1; transform: none; }
}