/* =========================================================================
   PayoffPilot — Early Payoff Calculator
   Design tokens (warm, credible fintech): beige canvas, off-white cards,
   lime + orange accents, near-black ink. 2 fonts: Fraunces + Inter.
   ========================================================================= */
:root {
    --bg:            #e7e4da;   /* warm beige canvas */
    --surface:       #efece3;   /* soft card */
    --surface-2:     #f6f4ee;   /* input fill */
    --ink:           #1c1b18;   /* near-black text */
    --ink-soft:      #6f6c63;   /* muted text */
    --line:          #d8d4c7;   /* hairline borders */
    --lime:          #d6f24f;   /* highlight accent */
    --lime-ink:      #23260a;   /* text on lime */
    --orange:        #f0925b;   /* secondary accent */
    --orange-ink:    #2c1608;   /* text on orange */
    --white:         #ffffff;
    --radius:        22px;
    --radius-sm:     14px;
    --shadow:        0 1px 2px rgba(28,27,24,.05), 0 12px 30px -18px rgba(28,27,24,.35);
    --maxw:          1120px;
    --font-sans:     'Inter', system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
    --font-serif:    'Fraunces', Georgia, 'Times New Roman', serif;
}

* { box-sizing: border-box; }
html.theme { background: var(--bg); }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
    margin: 0;
    background: var(--bg);
    color: var(--ink);
    font-family: var(--font-sans);
    font-size: 16px;
    line-height: 1.55;
    -webkit-font-smoothing: antialiased;
}

h1, h2, h3 { font-family: var(--font-serif); font-weight: 600; line-height: 1.1; margin: 0; letter-spacing: -.01em; }
p { margin: 0; }
a { color: inherit; text-decoration: none; }
img, svg { display: block; max-width: 100%; }
.text-balance { text-wrap: balance; }
.text-pretty  { text-wrap: pretty; }

.container { width: 100%; max-width: var(--maxw); margin-inline: auto; padding-inline: 20px; }

.skip-link {
    position: absolute; left: -999px; top: 0; z-index: 100;
    background: var(--ink); color: var(--bg); padding: 10px 16px; border-radius: 0 0 10px 0;
}
.skip-link:focus { left: 0; }

:focus-visible { outline: 3px solid var(--ink); outline-offset: 2px; border-radius: 6px; }

/* ---------------------------------------------------------------- Buttons */
.btn {
    display: inline-flex; align-items: center; justify-content: center; gap: 8px;
    font-weight: 600; font-size: 15px; border: 0; cursor: pointer;
    padding: 14px 22px; border-radius: 999px; transition: transform .12s ease, background .2s ease, opacity .2s ease;
}
.btn:active { transform: translateY(1px); }
.btn-dark { background: var(--ink); color: var(--bg); }
.btn-dark:hover { background: #000; }
.btn-block { width: 100%; margin-top: 6px; }

/* ---------------------------------------------------------------- Header */
.site-header { position: sticky; top: 0; z-index: 40; background: color-mix(in srgb, var(--bg) 88%, transparent); backdrop-filter: blur(8px); border-bottom: 1px solid var(--line); }
.header-inner { display: flex; align-items: center; justify-content: space-between; height: 68px; }
.brand { display: inline-flex; align-items: center; gap: 10px; font-weight: 700; }
.brand-mark { display: grid; place-items: center; width: 38px; height: 38px; border-radius: 12px; background: var(--ink); color: var(--lime); }
.brand-name { font-family: var(--font-serif); font-size: 20px; letter-spacing: -.02em; }

.site-nav { display: flex; align-items: center; }
.nav-menu { display: flex; align-items: center; gap: 6px; list-style: none; margin: 0; padding: 0; }
.nav-menu a { padding: 9px 14px; border-radius: 999px; font-weight: 500; color: var(--ink-soft); }
.nav-menu a:hover { color: var(--ink); }
.nav-menu a.active { color: var(--ink); background: var(--surface); }
.nav-menu a.nav-cta { background: var(--ink); color: var(--bg); }
.nav-menu a.nav-cta:hover { color: var(--bg); }
.nav-toggle { display: none; flex-direction: column; gap: 5px; background: none; border: 0; padding: 10px; cursor: pointer; }
.nav-toggle span { width: 22px; height: 2px; background: var(--ink); border-radius: 2px; }

/* ---------------------------------------------------------------- Hero */
.hero { padding: 72px 0 44px; }
.hero-inner { max-width: 760px; }
.eyebrow { text-transform: uppercase; letter-spacing: .14em; font-size: 12px; font-weight: 600; color: var(--ink-soft); margin-bottom: 16px; }
.hero-title { font-size: clamp(2.4rem, 6vw, 4.2rem); }
.hero-title .hl { background: var(--lime); padding: 0 .12em; border-radius: 10px; }
.hero-sub { margin-top: 20px; font-size: clamp(1.05rem, 2vw, 1.25rem); color: var(--ink-soft); max-width: 620px; }
.hero-btn { margin-top: 28px; }

/* ---------------------------------------------------------------- Cards */
.card { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 26px; box-shadow: var(--shadow); }
.card-title { font-size: 1.15rem; margin-bottom: 16px; }
.card-title-mt { margin-top: 26px; }

/* ---------------------------------------------------------------- Calc layout */
.calc-section { padding: 24px 0 40px; }
.calc-grid { display: grid; grid-template-columns: 1.05fr .95fr; gap: 20px; align-items: start; }
.results-col { display: grid; gap: 20px; }

/* Inputs */
.field-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.field { display: flex; flex-direction: column; gap: 8px; }
.field label { font-size: 13px; font-weight: 600; color: var(--ink-soft); }
.input-wrap { position: relative; display: flex; align-items: center; background: var(--surface-2); border: 1px solid var(--line); border-radius: var(--radius-sm); transition: border-color .15s ease, box-shadow .15s ease; }
.input-wrap:focus-within { border-color: var(--ink); box-shadow: 0 0 0 3px color-mix(in srgb, var(--ink) 12%, transparent); }
.input-wrap input, .input-wrap select { width: 100%; border: 0; background: transparent; padding: 13px 14px; font: inherit; font-weight: 600; color: var(--ink); outline: none; border-radius: var(--radius-sm); }
.input-wrap select { appearance: none; cursor: pointer; padding-right: 34px; }
.input-wrap .affix { padding-left: 14px; color: var(--ink-soft); font-weight: 600; }
.input-wrap .affix + input { padding-left: 6px; }
.input-wrap .affix-right { position: absolute; right: 14px; color: var(--ink-soft); font-weight: 600; pointer-events: none; }
.field-hint { font-size: 12px; color: var(--ink-soft); }

.slider { -webkit-appearance: none; appearance: none; width: 100%; height: 6px; border-radius: 999px; background: var(--line); margin-top: 4px; cursor: pointer; }
.slider::-webkit-slider-thumb { -webkit-appearance: none; width: 20px; height: 20px; border-radius: 50%; background: var(--ink); border: 3px solid var(--surface); }
.slider::-moz-range-thumb { width: 20px; height: 20px; border: 3px solid var(--surface); border-radius: 50%; background: var(--ink); }

.form-error { margin-top: 12px; color: #8a2b12; background: #f6dfd4; border: 1px solid #e6b7a2; padding: 10px 14px; border-radius: 12px; font-size: 14px; }

/* Accent result cards */
.accent-card { position: relative; overflow: hidden; }
.accent-lime { background: var(--lime); border-color: color-mix(in srgb, var(--lime) 70%, #000 6%); color: var(--lime-ink); }
.accent-orange { background: var(--orange); border-color: color-mix(in srgb, var(--orange) 70%, #000 6%); color: var(--orange-ink); }
.accent-head { display: flex; align-items: center; justify-content: space-between; font-size: 13px; font-weight: 600; text-transform: uppercase; letter-spacing: .08em; opacity: .8; }
.accent-figure { font-family: var(--font-serif); font-size: clamp(2.6rem, 6vw, 3.6rem); font-weight: 600; margin-top: 8px; line-height: 1; letter-spacing: -.02em; }
.accent-sub { margin-top: 10px; font-size: 1rem; }
.dot-grid { width: 74px; height: 40px; background-image: radial-gradient(currentColor 1.4px, transparent 1.6px); background-size: 10px 10px; opacity: .35; border-radius: 4px; }
.hatch { width: 74px; height: 40px; background-image: repeating-linear-gradient(45deg, currentColor 0 2px, transparent 2px 8px); opacity: .3; border-radius: 4px; }

.mini-stats { display: grid; grid-template-columns: 1fr 1fr; gap: 16px 22px; margin-top: 18px; }
.mini-label { display: block; font-size: 12.5px; opacity: .8; }
.mini-value { display: block; font-family: var(--font-serif); font-size: 1.5rem; font-weight: 600; margin-top: 2px; }
.mini-value.strike { text-decoration: line-through; opacity: .6; font-size: 1.25rem; }

/* Chart */
.chart-card { padding-bottom: 20px; }
.chart-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: 12px; gap: 12px; flex-wrap: wrap; }
.legend { display: flex; gap: 16px; font-size: 13px; color: var(--ink-soft); }
.legend-item { display: inline-flex; align-items: center; gap: 7px; }
.sw { width: 14px; height: 4px; border-radius: 2px; display: inline-block; }
.sw-base { background: var(--ink-soft); }
.sw-accel { background: var(--orange); }
.chart { width: 100%; height: 220px; }
.chart svg { width: 100%; height: 100%; overflow: visible; }

/* ---------------------------------------------------------------- Features */
.features { padding: 40px 0 72px; }
.section-title { font-size: clamp(1.8rem, 4vw, 2.6rem); max-width: 620px; margin-bottom: 28px; }
.feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.feature h3 { font-size: 1.2rem; margin: 14px 0 8px; }
.feature p { color: var(--ink-soft); }
.feature-icon { display: grid; place-items: center; width: 46px; height: 46px; border-radius: 14px; background: var(--lime); color: var(--lime-ink); }

/* ---------------------------------------------------------------- Content pages */
.page { padding: 56px 0 72px; }
.page-head { max-width: 720px; margin-bottom: 36px; }
.page-head h1 { font-size: clamp(2.1rem, 5vw, 3.2rem); }
.page-head .lede { margin-top: 16px; font-size: 1.15rem; color: var(--ink-soft); }
.prose { max-width: 760px; }
.prose h2 { font-size: 1.6rem; margin: 36px 0 12px; }
.prose h3 { font-size: 1.25rem; margin: 24px 0 8px; }
.prose p, .prose li { color: var(--ink); }
.prose p { margin-bottom: 14px; }
.prose ul, .prose ol { margin: 0 0 16px; padding-left: 22px; }
.prose li { margin-bottom: 8px; }
.prose .formula { font-family: var(--font-serif); background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius-sm); padding: 16px 18px; font-size: 1.15rem; margin: 16px 0; }

.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; margin: 28px 0 8px; }
.step { position: relative; }
.step .num { font-family: var(--font-serif); font-size: 2rem; color: var(--orange); }
.step h3 { font-size: 1.15rem; margin: 6px 0; }
.step p { color: var(--ink-soft); }

/* FAQ */
.faq-list { max-width: 780px; display: grid; gap: 12px; }
details.faq-item { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius-sm); padding: 4px 6px; }
details.faq-item summary { cursor: pointer; list-style: none; padding: 16px 18px; font-weight: 600; font-size: 1.05rem; display: flex; justify-content: space-between; align-items: center; gap: 12px; }
details.faq-item summary::-webkit-details-marker { display: none; }
details.faq-item summary::after { content: "+"; font-size: 1.4rem; color: var(--ink-soft); transition: transform .2s ease; }
details.faq-item[open] summary::after { transform: rotate(45deg); }
details.faq-item .faq-body { padding: 0 18px 18px; color: var(--ink-soft); }

.cta-band { background: var(--ink); color: var(--bg); border-radius: var(--radius); padding: 40px; margin-top: 48px; display: flex; align-items: center; justify-content: space-between; gap: 24px; flex-wrap: wrap; }
.cta-band h2 { color: var(--bg); font-size: 1.8rem; }
.cta-band .btn { background: var(--lime); color: var(--lime-ink); }

/* ---------------------------------------------------------------- Footer */
.site-footer { border-top: 1px solid var(--line); background: var(--surface); margin-top: 20px; }
.footer-grid { display: grid; grid-template-columns: 1.6fr 1fr 1fr 1.4fr; gap: 28px; padding: 48px 20px 32px; }
.footer-desc { color: var(--ink-soft); margin-top: 14px; max-width: 320px; font-size: 14.5px; }
.footer-heading { font-family: var(--font-sans); font-size: 13px; text-transform: uppercase; letter-spacing: .1em; color: var(--ink-soft); margin-bottom: 12px; }
.site-footer ul { list-style: none; margin: 0; padding: 0; display: grid; gap: 8px; }
.site-footer a { color: var(--ink); font-size: 14.5px; }
.site-footer a:hover { color: var(--orange); }
.footer-note p { color: var(--ink-soft); font-size: 13.5px; }
.footer-bottom { display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; padding: 20px; border-top: 1px solid var(--line); color: var(--ink-soft); font-size: 13px; }

/* ---------------------------------------------------------------- Responsive */
@media (max-width: 900px) {
    .calc-grid { grid-template-columns: 1fr; }
    .feature-grid, .steps { grid-template-columns: 1fr; }
    .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 640px) {
    .nav-toggle { display: flex; }
    .nav-menu {
        position: absolute; top: 68px; left: 0; right: 0;
        flex-direction: column; align-items: stretch; gap: 4px;
        background: var(--surface); border-bottom: 1px solid var(--line);
        padding: 12px 20px 18px; display: none;
    }
    .nav-menu.open { display: flex; }
    .nav-menu a { padding: 12px 14px; }
    .field-grid, .mini-stats { grid-template-columns: 1fr; }
    .footer-grid { grid-template-columns: 1fr; }
    .cta-band { padding: 28px; }
}

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