:root {
    color-scheme: light;
    --bg: #f5f7f4;
    --surface: #ffffff;
    --surface-2: #eef3ef;
    --text: #15211b;
    --muted: #5d6c64;
    --line: #d9dfd9;
    --line-strong: #c3ccc4;
    --accent: #176b5b;
    --accent-strong: #0e4b40;
    --accent-soft: #e2efea;
    --accent-contrast: #ffffff;
    --focus: #b54a2b;
    --danger: #b54a2b;
    --danger-bg: #fff5f0;
    --radius: 14px;
    --radius-sm: 8px;
    --shadow: 0 1px 2px rgba(21, 33, 27, 0.05), 0 12px 32px -18px rgba(21, 33, 27, 0.25);
    --shadow-hover: 0 2px 4px rgba(21, 33, 27, 0.06), 0 18px 40px -18px rgba(21, 33, 27, 0.3);
    --tone-green-bg: #e2efea;
    --tone-green-fg: #176b5b;
    --tone-amber-bg: #fbf0dc;
    --tone-amber-fg: #9a6410;
    --tone-teal-bg: #dcf0f0;
    --tone-teal-fg: #0f6b6b;
    --tone-violet-bg: #ebe7fa;
    --tone-violet-fg: #5b45b0;
    --tone-blue-bg: #e3ecf9;
    --tone-blue-fg: #2c5aa0;
    --content-width: 1080px;
}

* {
    box-sizing: border-box;
}

html {
    -webkit-text-size-adjust: 100%;
}

body {
    margin: 0;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    background: var(--bg);
    color: var(--text);
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    line-height: 1.55;
}

a {
    color: var(--accent-strong);
}

a:focus-visible,
button:focus-visible,
summary:focus-visible {
    outline: 3px solid var(--focus);
    outline-offset: 3px;
}

h1,
h2,
h3 {
    line-height: 1.15;
    letter-spacing: -0.01em;
}

h1 {
    margin: 0 0 0.75rem;
    font-size: clamp(2rem, 1.6rem + 1.6vw, 3rem);
}

h2 {
    margin: 0 0 1rem;
    font-size: 1.4rem;
}

h3 {
    margin: 0;
    font-size: 1.1rem;
}

p {
    margin: 0 0 1rem;
}

code {
    font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
    font-size: 0.95em;
}

/* Icons */

.icon {
    width: 1.25em;
    height: 1.25em;
    flex: none;
    vertical-align: -0.28em;
}

.icon-tile {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 2.75rem;
    height: 2.75rem;
    flex: none;
    border-radius: 12px;
    background: var(--tone-bg, var(--accent-soft));
    color: var(--tone-fg, var(--accent));
}

.icon-tile .icon {
    width: 1.5rem;
    height: 1.5rem;
}

.icon-tile--large {
    width: 3.5rem;
    height: 3.5rem;
    border-radius: 16px;
}

.icon-tile--large .icon {
    width: 1.9rem;
    height: 1.9rem;
}

.icon-tile--small {
    width: 2.25rem;
    height: 2.25rem;
    border-radius: 10px;
}

.icon-tile--small .icon {
    width: 1.25rem;
    height: 1.25rem;
}

.tone-green {
    --tone-bg: var(--tone-green-bg);
    --tone-fg: var(--tone-green-fg);
}

.tone-amber {
    --tone-bg: var(--tone-amber-bg);
    --tone-fg: var(--tone-amber-fg);
}

.tone-teal {
    --tone-bg: var(--tone-teal-bg);
    --tone-fg: var(--tone-teal-fg);
}

.tone-violet {
    --tone-bg: var(--tone-violet-bg);
    --tone-fg: var(--tone-violet-fg);
}

.tone-blue {
    --tone-bg: var(--tone-blue-bg);
    --tone-fg: var(--tone-blue-fg);
}

/* Layout */

.skip-link {
    position: absolute;
    left: 1rem;
    top: -4rem;
    z-index: 10;
    background: var(--text);
    color: #ffffff;
    padding: 0.75rem 1rem;
    border-radius: var(--radius-sm);
}

.skip-link:focus {
    top: 1rem;
}

.site-header {
    border-bottom: 1px solid var(--line);
    background: var(--surface);
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    max-width: var(--content-width);
    margin: 0 auto;
    padding: 0.85rem 1rem;
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 0.6rem;
    color: var(--text);
    font-weight: 800;
    font-size: 1.1rem;
    text-decoration: none;
}

.brand-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 2.1rem;
    height: 2.1rem;
    border-radius: 9px;
    background: var(--accent);
    color: var(--accent-contrast);
}

.brand-icon .icon {
    width: 1.3rem;
    height: 1.3rem;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 0.25rem;
}

.nav-links a {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.5rem 0.75rem;
    border-radius: var(--radius-sm);
    color: var(--text);
    font-weight: 600;
    text-decoration: none;
}

.nav-links a:hover {
    background: var(--surface-2);
}

.page {
    flex: 1;
    width: 100%;
    max-width: var(--content-width);
    margin: 0 auto;
    padding: 1.5rem 1rem 4rem;
}

.site-footer {
    margin-top: auto;
    border-top: 1px solid var(--line);
    background: var(--surface);
}

.footer-inner {
    display: grid;
    grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr) minmax(0, 1fr);
    gap: 2rem 3rem;
    max-width: var(--content-width);
    margin: 0 auto;
    padding: 2.5rem 1rem 2rem;
}

.footer-brand p {
    color: var(--muted);
    margin: 0.85rem 0 0;
    max-width: 36ch;
}

.footer-title {
    margin: 0.35rem 0 0.85rem;
    font-size: 0.8rem;
    font-weight: 800;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--muted);
}

.footer-links {
    list-style: none;
    margin: 0;
    padding: 0;
    display: grid;
    gap: 0.55rem;
}

.footer-links a {
    display: inline-flex;
    align-items: center;
    gap: 0.6rem;
    color: var(--text);
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 500;
}

.footer-links a:hover,
.footer-link-button:hover {
    color: var(--accent-strong);
}

.footer-link-button {
    display: inline-flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0;
    border: 0;
    background: none;
    color: var(--text);
    cursor: pointer;
    font: inherit;
    font-size: 0.95rem;
    font-weight: 500;
}

.footer-links a:hover .footer-link-icon,
.footer-link-button:hover .footer-link-icon {
    background: var(--tone-bg, var(--accent-soft));
    color: var(--tone-fg, var(--accent-strong));
}

.footer-link-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 1.75rem;
    height: 1.75rem;
    flex: none;
    border-radius: 8px;
    background: var(--surface-2);
    color: var(--muted);
    transition: background-color 0.15s ease, color 0.15s ease;
}

.footer-link-icon .icon {
    width: 1rem;
    height: 1rem;
}

.footer-note {
    max-width: var(--content-width);
    margin: 0 auto;
    padding: 1rem 1rem 1.5rem;
    border-top: 1px solid var(--line);
    color: var(--muted);
    font-size: 0.85rem;
}

/* Hero and homepage */

.hero {
    display: grid;
    grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
    gap: 2rem;
    align-items: center;
    padding: 2.5rem 0 3rem;
}

.hero p {
    font-size: 1.1rem;
    color: var(--muted);
    max-width: 58ch;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-top: 1.5rem;
}

.hero-panel {
    display: grid;
    gap: 0.75rem;
    padding: 1.25rem;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: var(--surface);
    box-shadow: var(--shadow);
}

.hero-panel-item {
    display: flex;
    align-items: flex-start;
    gap: 0.85rem;
}

.hero-panel-item strong {
    display: block;
}

.hero-panel-item span {
    color: var(--muted);
    font-size: 0.95rem;
}

.eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    margin: 0 0 1rem;
    padding: 0.3rem 0.7rem;
    border-radius: 999px;
    background: var(--accent-soft);
    color: var(--accent-strong);
    font-size: 0.8rem;
    font-weight: 700;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

.section {
    border-top: 1px solid var(--line);
    padding: 2rem 0;
}

.section-heading {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.section-heading h2 {
    margin: 0;
}

.section-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 2.1rem;
    height: 2.1rem;
    flex: none;
    border-radius: 999px;
    background: var(--accent-soft);
    color: var(--accent-strong);
}

.section-icon .icon {
    width: 1.15rem;
    height: 1.15rem;
}

.section-lead {
    color: var(--muted);
    max-width: 62ch;
}

.category {
    padding: 1.5rem 0;
}

.category + .category {
    border-top: 1px dashed var(--line);
}

.category-heading {
    display: flex;
    align-items: center;
    gap: 0.9rem;
    margin-bottom: 1rem;
}

.category-heading p {
    margin: 0.1rem 0 0;
    color: var(--muted);
}

.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(230px, 1fr));
    gap: 0.85rem;
    margin: 0;
    padding: 0;
    list-style: none;
}

.card {
    display: flex;
    align-items: flex-start;
    gap: 0.85rem;
    height: 100%;
    padding: 1rem;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: var(--surface);
    color: var(--text);
    text-decoration: none;
    transition: transform 0.15s ease, box-shadow 0.15s ease, border-color 0.15s ease;
}

.card:hover {
    transform: translateY(-2px);
    border-color: var(--line-strong);
    box-shadow: var(--shadow-hover);
}

.card-body {
    display: grid;
    gap: 0.2rem;
    min-width: 0;
}

.card-title {
    font-weight: 700;
}

.card-text {
    color: var(--muted);
    font-size: 0.92rem;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 1rem;
}

.feature {
    display: flex;
    gap: 0.9rem;
    align-items: flex-start;
}

.feature p {
    margin: 0.2rem 0 0;
    color: var(--muted);
}

.check-list {
    display: grid;
    gap: 0.75rem;
    padding-left: 1.25rem;
}

/* Buttons */

.button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    border: 1px solid transparent;
    border-radius: 10px;
    background: var(--accent);
    color: var(--accent-contrast);
    cursor: pointer;
    font: inherit;
    font-weight: 700;
    padding: 0.8rem 1.15rem;
    text-decoration: none;
    transition: background-color 0.15s ease, transform 0.15s ease;
}

.button:hover {
    background: var(--accent-strong);
}

.button:active {
    transform: translateY(1px);
}

.button:disabled {
    opacity: 0.7;
    cursor: progress;
}

.button--secondary {
    background: var(--surface);
    border-color: var(--line-strong);
    color: var(--text);
}

.button--secondary:hover {
    background: var(--surface-2);
}

.button--small {
    padding: 0.45rem 0.75rem;
    font-size: 0.85rem;
    border-radius: 8px;
}

.copy-button {
    margin-left: auto;
}

/* Breadcrumb */

.breadcrumb {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.5rem;
    color: var(--muted);
    font-size: 0.92rem;
    margin-bottom: 1.25rem;
}

.breadcrumb a {
    color: var(--muted);
}

.breadcrumb a::after {
    content: "/";
    color: var(--line-strong);
    margin-left: 0.5rem;
}

/* Calculator page */

.calculator-page {
    max-width: 820px;
}

.intro {
    display: flex;
    gap: 1rem;
    align-items: flex-start;
    margin-bottom: 1.5rem;
}

.intro p {
    margin: 0;
    color: var(--muted);
    font-size: 1.05rem;
}

.calculator-form {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    column-gap: 1rem;
    row-gap: 0.4rem;
    align-items: start;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: var(--surface);
    box-shadow: var(--shadow);
    padding: 0.65rem 1.25rem 1.25rem;
    margin-bottom: 1.5rem;
}

.form-wide {
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
}

/* Each field spans the label, input and error tracks of the form grid, so fields on the same
   row keep their inputs aligned even when one label wraps onto two lines. */
.field {
    display: grid;
    grid-row: span 3;
    grid-template-rows: subgrid;
    row-gap: 0.4rem;
}

.field label {
    align-self: end;
    margin-top: 0.6rem;
    font-weight: 700;
    font-size: 0.95rem;
    line-height: 1.3;
}

.required-marker {
    display: inline-block;
    white-space: nowrap;
    margin-left: 0.35rem;
    padding: 0.1rem 0.4rem;
    border-radius: 999px;
    background: var(--accent-soft);
    color: var(--accent-strong);
    font-size: 0.62rem;
    font-weight: 800;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    vertical-align: middle;
}

.field[hidden] {
    display: none;
}

.field--invalid input {
    border-color: var(--danger);
}

.field-error {
    margin: 0;
    color: var(--danger);
    font-size: 0.9rem;
}

.field input,
.field select {
    width: 100%;
    border: 1px solid var(--line-strong);
    border-radius: 10px;
    background: var(--surface);
    color: var(--text);
    font: inherit;
    padding: 0.75rem 0.85rem;
    transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.field input:focus,
.field select:focus {
    border-color: var(--accent);
    outline: none;
    box-shadow: 0 0 0 4px var(--accent-soft);
}

.calculator-form .button {
    grid-column: 1 / -1;
    justify-self: start;
    margin-top: 0.6rem;
    min-height: 3rem;
}

.error-list {
    grid-column: 1 / -1;
    margin-top: 0.6rem;
    display: flex;
    gap: 0.75rem;
    border: 1px solid #f0c9b8;
    border-left: 4px solid var(--danger);
    border-radius: var(--radius-sm);
    background: var(--danger-bg);
    padding: 0.85rem 1rem;
}

.error-list .icon {
    color: var(--danger);
    margin-top: 0.15rem;
}

.error-list p,
.error-list ul {
    margin: 0.15rem 0;
}

.error-list ul {
    padding-left: 1.1rem;
}

/* Result */

.result-panel {
    position: relative;
    overflow: hidden;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: var(--surface);
    box-shadow: var(--shadow);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}

.result-panel::before {
    content: "";
    position: absolute;
    inset: 0 0 auto 0;
    height: 5px;
    background: linear-gradient(90deg, var(--accent), #4aa58f);
}

.result-panel:focus,
.error-list:focus {
    outline: 3px solid rgba(181, 74, 43, 0.25);
    outline-offset: 3px;
}

.result-heading {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    margin-bottom: 0.75rem;
}

.result-heading h2 {
    margin: 0;
    font-size: 1.05rem;
    color: var(--muted);
    font-weight: 700;
    letter-spacing: 0.02em;
    text-transform: uppercase;
}

.result-heading .icon {
    color: var(--accent);
}

.result-label {
    margin: 0;
    color: var(--muted);
    font-weight: 600;
}

.result-value {
    color: var(--accent-strong);
    font-size: clamp(2.2rem, 2rem + 1.5vw, 3rem);
    font-weight: 850;
    line-height: 1.05;
    letter-spacing: -0.02em;
    margin: 0.2rem 0 0.6rem;
}

.result-note {
    color: var(--muted);
    margin: 0 0 0.5rem;
}

.result-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 0.75rem;
    margin: 1rem 0 0;
}

.result-list div {
    border-radius: var(--radius-sm);
    background: var(--surface-2);
    padding: 0.75rem 0.9rem;
}

.result-list dt {
    color: var(--muted);
    font-size: 0.85rem;
}

.result-list dd {
    font-weight: 800;
    font-size: 1.1rem;
    margin: 0.15rem 0 0;
}

.formula {
    display: grid;
    gap: 0.35rem;
    margin: 0;
    padding: 0.9rem 1rem;
    border-radius: var(--radius-sm);
    background: var(--surface-2);
    overflow-x: auto;
}

.formula code {
    display: block;
    white-space: nowrap;
}

.formula--values {
    margin-top: 0.6rem;
    background: var(--accent-soft);
    color: var(--accent-strong);
}

.steps {
    display: grid;
    gap: 0.85rem;
    margin: 0;
    padding: 0;
    list-style: none;
    counter-reset: step;
}

.steps li {
    position: relative;
    padding-left: 2.6rem;
    counter-increment: step;
}

.steps li::before {
    content: counter(step);
    position: absolute;
    left: 0;
    top: 0;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 1.9rem;
    height: 1.9rem;
    border-radius: 999px;
    background: var(--accent-soft);
    color: var(--accent-strong);
    font-weight: 800;
    font-size: 0.9rem;
}

.steps li span {
    display: block;
    margin-top: 0.1rem;
    word-break: break-word;
}

.steps .step-formula {
    color: var(--muted);
    font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
    font-size: 0.88rem;
}

.steps .step-value {
    font-weight: 700;
    color: var(--accent-strong);
}

.note-list {
    display: grid;
    gap: 0.6rem;
    margin: 0;
    padding: 0;
    list-style: none;
}

.note-list li {
    display: flex;
    gap: 0.6rem;
    align-items: flex-start;
}

.note-list .icon {
    margin-top: 0.2rem;
    color: var(--accent);
}

.note-list li.is-warning .icon {
    color: var(--danger);
}

.bullet-list {
    display: grid;
    gap: 0.5rem;
    margin: 0;
    padding-left: 1.25rem;
}

.faq details {
    border: 1px solid var(--line);
    border-radius: var(--radius-sm);
    background: var(--surface);
    padding: 0 1rem;
}

.faq details + details {
    margin-top: 0.6rem;
}

.faq summary {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem;
    cursor: pointer;
    list-style: none;
    padding: 0.85rem 0;
    font-weight: 700;
}

.faq summary::-webkit-details-marker {
    display: none;
}

.faq summary .icon {
    color: var(--muted);
    transition: transform 0.2s ease;
}

.faq details[open] summary .icon {
    transform: rotate(180deg);
}

.faq details p {
    margin: 0 0 1rem;
    color: var(--muted);
}

/* Notices and monetization */

.notice {
    border-left: 4px solid var(--accent);
    background: var(--surface);
    padding: 0.75rem 1rem;
}

.small {
    color: var(--muted);
    font-size: 0.95rem;
}

.monetization-slot {
    max-width: var(--content-width);
    min-height: 92px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 0.25rem;
    margin: 1rem auto;
    border: 1px dashed #b54a2b;
    border-radius: var(--radius-sm);
    background: #fff7f3;
    color: #7d321d;
    padding: 1rem;
    text-align: center;
    box-shadow: inset 0 0 0 1px rgba(181, 74, 43, 0.08);
}

.monetization-slot__eyebrow {
    color: #9a3f25;
    font-size: 0.75rem;
    font-weight: 800;
    text-transform: uppercase;
}

.monetization-slot strong {
    font-size: 1rem;
}

.monetization-slot small {
    color: #8c4a35;
}

.affiliate-disclosure {
    max-width: var(--content-width);
    margin: 0 auto 2rem;
    padding: 0 1rem;
    color: var(--muted);
    font-size: 0.9rem;
}

/* Responsive */

@media (max-width: 820px) {
    .hero {
        grid-template-columns: 1fr;
        padding: 1.5rem 0 2rem;
    }

    .footer-inner {
        grid-template-columns: repeat(2, minmax(0, 1fr));
        gap: 1.75rem 2rem;
    }

    .footer-brand {
        grid-column: 1 / -1;
    }
}

@media (max-width: 720px) {
    .monetization-slot {
        margin-left: 1rem;
        margin-right: 1rem;
    }

    .calculator-form .button {
        justify-self: stretch;
    }

    .intro {
        flex-direction: column;
    }
}

@media (max-width: 480px) {
    .footer-inner {
        grid-template-columns: 1fr;
    }

    .nav-links a span {
        display: none;
    }
}

@media (prefers-reduced-motion: reduce) {
    .card,
    .button,
    .faq summary .icon {
        transition: none;
    }
}