/* Kerbtest test screens, full screen and phone first.
   Uses the site's theme variables (--bg, --ink, --muted, --accent, --accentInk, --line, --surface, --r, --font, --head).
   Variant touches are at the bottom (.v-a, .v-b, .v-c on <body>). */
html.ktf-on, html.ktf-on body { overflow: hidden; }
.ktf { position: fixed; inset: 0; z-index: 50; display: grid; grid-template-rows: auto minmax(0, 1fr) auto; height: 100vh; height: 100dvh; background: var(--bg); color: var(--ink); font-family: var(--font, system-ui, sans-serif); }
.ktf [tabindex="-1"]:focus, .ktf [tabindex="-1"]:focus-visible { outline: none; }
.ktf-sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; }

/* top bar: exit, progress count, timer */
.ktf-top { background: var(--ktf-bar, var(--bg)); color: var(--ktf-bar-ink, var(--ink)); border-bottom: 1px solid var(--line); padding-top: env(safe-area-inset-top); }
.ktf-top-in { width: min(760px, 100% - 24px); margin-inline: auto; display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; min-height: 56px; }
.ktf-exit { justify-self: start; display: inline-flex; align-items: center; gap: 6px; min-height: 44px; padding: 0 8px; margin-left: -8px; color: inherit; opacity: .75; text-decoration: none; font-size: .95rem; }
.ktf-exit span { font-size: 1.5rem; line-height: 1; }
.ktf-exit:hover, .ktf-exit:focus-visible { opacity: 1; }
.ktf-brand { font: 600 1rem var(--head, inherit); }
.ktf-count { font-size: .95rem; color: inherit; }
.ktf-count strong { font: 700 1.25rem var(--head, inherit); }
.ktf-spacer { justify-self: end; }
.ktf-time { justify-self: end; display: inline-flex; align-items: center; gap: 7px; padding: 6px 12px; border-radius: 999px; background: var(--surface); color: var(--ink); font-size: .95rem; }
.ktf-time strong { font-variant-numeric: tabular-nums; font-size: 1.05rem; }
.ktf-time.kt-low { background: #b3261e; color: #fff; }
.ktf-clock { width: 12px; height: 12px; border: 2px solid currentColor; border-radius: 50%; position: relative; }
.ktf-clock::after { content: ''; position: absolute; left: 3px; top: 0; width: 2px; height: 4px; background: currentColor; }
.ktf-progress { height: 4px; background: color-mix(in srgb, var(--line) 70%, transparent); }
.ktf-progress span { display: block; height: 100%; background: var(--accent); transition: width .3s ease; }

/* body: the question, scrolls on its own */
.ktf-body { overflow-y: auto; overscroll-behavior: contain; -webkit-overflow-scrolling: touch; }
.ktf-wrap { width: min(720px, 100% - 32px); margin-inline: auto; min-height: 100%; display: flex; flex-direction: column; padding: 18px 0 24px; }
.ktf-sec { margin: 0 0 10px; font-size: .8rem; font-weight: 700; letter-spacing: .08em; text-transform: uppercase; color: var(--muted); }
.ktf-flagtag { margin-left: 8px; padding: 2px 8px; border-radius: 999px; background: #fff0d6; color: #7a4800; letter-spacing: 0; text-transform: none; }
.ktf-sign { margin: 4px auto 18px; }
.ktf-sign img { width: clamp(132px, 30vh, 240px); height: clamp(132px, 30vh, 240px); object-fit: contain; filter: drop-shadow(0 6px 14px rgb(0 0 0 / .12)); }
.ktf-q { margin: 0; font: 650 clamp(1.25rem, 1rem + 1.6vw, 1.75rem)/1.32 var(--font, system-ui); letter-spacing: -0.01em; outline: none; }
.ktf-trap { margin: 14px 0 0; padding: 10px 14px; border-left: 4px solid var(--accent); background: var(--surface); border-radius: 0 var(--r, 8px) var(--r, 8px) 0; font-size: .95rem; }
.ktf-opts { display: grid; gap: 10px; margin-top: auto; padding-top: 22px; }
.ktf-opt { display: flex; align-items: center; gap: 14px; width: 100%; min-height: 62px; padding: 14px 16px; text-align: left; border: 2px solid var(--line); border-radius: var(--r, 8px); background: var(--bg); color: var(--ink); font: inherit; font-size: 1.05rem; line-height: 1.38; cursor: pointer; -webkit-tap-highlight-color: transparent; transition: transform .12s ease, border-color .15s ease, background-color .15s ease; }
.ktf-opt:hover:not(:disabled) { border-color: var(--accent); }
.ktf-opt:active:not(:disabled) { transform: scale(.985); }
.ktf-opt:focus-visible { outline: 3px solid var(--accent); outline-offset: 2px; }
.ktf-l { flex: none; display: inline-grid; place-items: center; width: 34px; height: 34px; border-radius: 50%; border: 2px solid var(--line); font-weight: 700; font-size: .95rem; }
.ktf-opt.kt-picked { border-color: var(--accent); background: var(--surface); }
.ktf-opt.kt-picked .ktf-l { background: var(--accent); border-color: var(--accent); color: var(--accentInk); }
.ktf-opt.kt-right { border-color: #2e7d4f; background: #e7f4ec; color: #14321f; }
.ktf-opt.kt-right .ktf-l { background: #2e7d4f; border-color: #2e7d4f; color: #fff; }
.ktf-opt.kt-wrong { border-color: #b3261e; background: #fbeae8; color: #3d0f0b; }
.ktf-opt.kt-wrong .ktf-l { background: #b3261e; border-color: #b3261e; color: #fff; }
.ktf-opt.kt-dim { opacity: .55; }
.ktf-opt:disabled { cursor: default; }
.ktf-explain { margin-top: 16px; padding: 16px 18px; border-radius: var(--r, 8px); background: var(--surface); border-left: 5px solid #2e7d4f; outline: none; }
.ktf-explain.kt-no { border-left-color: #b3261e; }
.ktf-explain p { margin: 0 0 8px; }
.ktf-verdict { font-weight: 800; font-size: 1.15rem; color: #1f5e3a; }
.kt-no .ktf-verdict { color: #9b1f18; }
.ktf-right { font-weight: 600; }
.kt-ref { font-size: .88rem; color: var(--muted); }
.kt-signdesc { background: var(--surface); padding: 10px 12px; border-radius: var(--r, 8px); font-size: .95rem; }

/* question overview (mock tests) */
.ktf-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(46px, 1fr)); gap: 6px; margin-top: 20px; padding-top: 16px; border-top: 1px solid var(--line); }
.ktf-grid button { min-height: 46px; border: 1px solid var(--line); border-radius: 8px; background: var(--bg); color: var(--ink); font: inherit; cursor: pointer; }
.ktf-grid .kt-done { background: var(--surface); font-weight: 700; }
.ktf-grid .kt-flag { border: 2px solid #b26a00; }
.ktf-grid .kt-here { outline: 3px solid var(--accent); outline-offset: 1px; }
.ktf-gridnote { grid-column: 1 / -1; margin: 8px 0 0; font-size: .95rem; color: var(--muted); }
.ktf-link { background: none; border: 0; padding: 6px 0; color: var(--accent); font: inherit; text-decoration: underline; cursor: pointer; }

/* bottom bar: the main button sits under the thumb */
.ktf-act { background: var(--bg); border-top: 1px solid var(--line); padding: 10px 0 calc(10px + env(safe-area-inset-bottom)); }
.ktf-act-in { width: min(720px, 100% - 24px); margin-inline: auto; display: flex; gap: 8px; }
.ktf-main { flex: 1; min-height: 56px; padding: 0 20px; border: 0; border-radius: var(--r, 8px); background: var(--accent); color: var(--accentInk); font: 700 1.08rem var(--font, system-ui); cursor: pointer; -webkit-tap-highlight-color: transparent; transition: transform .12s ease, opacity .15s ease; }
.ktf-main:disabled { opacity: .38; cursor: default; }
.ktf-main:active:not(:disabled) { transform: scale(.98); }
.ktf-main:focus-visible, .ktf-sub:focus-visible { outline: 3px solid var(--ink); outline-offset: 2px; }
.ktf-sub { flex: none; min-width: 56px; min-height: 56px; padding: 0 14px; border: 2px solid var(--line); border-radius: var(--r, 8px); background: transparent; color: var(--ink); font: 600 1rem var(--font, system-ui); cursor: pointer; }
.ktf-sub:disabled { opacity: .35; cursor: default; }
.ktf-sub.kt-flagged { border-color: #b26a00; color: #7a4800; background: #fff0d6; }
.ktf-gridicon { display: inline-block; width: 6px; height: 6px; margin-right: 8px; background: currentColor; box-shadow: 8px 0 currentColor, 0 8px currentColor, 8px 8px currentColor; vertical-align: 2px; }
@media (max-width: 479px) { .ktf-wide { display: none; } .ktf-gridicon { margin-right: 8px; } }

/* start and results screens */
.ktf-centre { justify-content: center; }
.ktf-kicker { margin: 0 0 8px; font-size: .85rem; font-weight: 700; letter-spacing: .08em; text-transform: uppercase; color: var(--accent); }
.ktf-title { margin: 0 0 12px; font: var(--headWeight, 600) clamp(2rem, 1.4rem + 3vw, 3.2rem)/1.08 var(--head, inherit); letter-spacing: -0.015em; outline: none; }
.ktf-intro { color: var(--muted); font-size: 1.08rem; max-width: 36em; }
.ktf-intro p { margin: 0 0 .8em; }
.ktf-facts { list-style: none; margin: 18px 0 0; padding: 0; display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; }
.ktf-facts li { padding: 14px; border-radius: var(--r, 8px); background: var(--surface); }
.ktf-facts strong { display: block; font: var(--headWeight, 600) 1.35rem/1.15 var(--head, inherit); }
.ktf-facts span { font-size: .88rem; color: var(--muted); }
.ktf-res .ktf-wrap { min-height: auto; padding-top: 28px; }
.ktf-score { --p: 0; width: 150px; aspect-ratio: 1; border-radius: 50%; margin: 0 0 18px; display: grid; place-items: center; background: conic-gradient(var(--accent) calc(var(--p) * 1%), var(--surface) 0); }
.ktf-score span { width: 120px; height: 120px; border-radius: 50%; background: var(--bg); display: grid; place-content: center; text-align: center; color: var(--muted); font-size: .95rem; line-height: 1.1; }
.ktf-score strong { font: var(--headWeight, 700) 2.8rem/1 var(--head, inherit); color: var(--ink); }
.ktf-subline { color: var(--muted); margin: 0 0 8px; }
.ktf-h2 { margin: 36px 0 8px; font: var(--headWeight, 600) 1.5rem/1.2 var(--head, inherit); }
.ktf-cta { margin: 8px 0 0; padding: 22px; border-radius: calc(var(--r, 8px) * 1.5); background: var(--ink); color: var(--bg); }
.ktf-cta h2 { margin: 0 0 8px; font: var(--headWeight, 600) clamp(1.5rem, 1.2rem + 1.4vw, 2rem)/1.15 var(--head, inherit); color: inherit; }
.ktf-cta p { margin: 0 0 14px; opacity: .85; }
.ktf-cta .ktf-cta-row { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; }
.ktf-cta .ktf-main { background: var(--bg); color: var(--ink); flex: 0 1 auto; display: inline-flex; align-items: center; justify-content: center; text-decoration: none; }
.ktf-cta a:not(.ktf-main) { color: inherit; }

/* results tables and review list (also used in the app) */
.kt-table { width: 100%; border-collapse: collapse; margin: 16px 0 24px; }
.kt-table th, .kt-table td { text-align: left; padding: 10px 8px; border-bottom: 1px solid var(--line); }
.kt-pass { color: #2e7d4f; font-weight: 700; }
.kt-fail { color: #b3261e; font-weight: 700; }
.kt-review { padding-left: 1.4em; }
.kt-review li { padding: 14px 0; border-bottom: 1px solid var(--line); overflow: hidden; }
.kt-review li p { margin: 0 0 6px; }
.kt-review .kt-rq { font-weight: 600; }
.kt-sign-sm { width: 72px; height: 72px; margin: 0 0 8px 12px; float: right; }
.kt-review li.kt-no { border-left: 3px solid #b3261e; padding-left: 10px; }
.kt-btn { display: inline-block; padding: 14px 20px; min-height: 50px; border-radius: var(--r, 8px); border: 0; background: var(--accent); color: var(--accentInk); font: 600 1rem var(--font, system-ui); text-decoration: none; cursor: pointer; }

@media (min-width: 900px) and (min-height: 680px) {
  .ktf-qwrap { justify-content: center; }
  .ktf-qwrap .ktf-opts { margin-top: 0; }
}

@media (prefers-reduced-motion: no-preference) {
  .ktf-enter { animation: ktf-in .34s cubic-bezier(.2, .7, .2, 1); }
  .ktf-back { animation: ktf-back .3s cubic-bezier(.2, .7, .2, 1); }
  .ktf-explain { animation: ktf-up .28s cubic-bezier(.2, .7, .2, 1); }
  .ktf-opt.kt-wrong { animation: ktf-shake .32s ease; }
  .ktf-opt.kt-right .ktf-l { animation: ktf-pop .3s ease; }
}
@keyframes ktf-in { from { opacity: 0; transform: translateX(24px); } }
@keyframes ktf-back { from { opacity: 0; transform: translateX(-24px); } }
@keyframes ktf-up { from { opacity: 0; transform: translateY(12px); } }
@keyframes ktf-shake { 25% { transform: translateX(-5px); } 50% { transform: translateX(5px); } 75% { transform: translateX(-3px); } }
@keyframes ktf-pop { 50% { transform: scale(1.18); } }

/* a: editorial. The question reads like a headline. */
.v-a .ktf-q { font: 400 clamp(1.6rem, 1.2rem + 2vw, 2.3rem)/1.18 var(--head); letter-spacing: -0.01em; }
.v-a .ktf-sec { color: var(--accent); }
.v-a .ktf-top { border-bottom: 3px double var(--line); }

/* b: road sign. Black bar, signal yellow, condensed caps. */
.v-b .ktf { --ktf-bar: #111; --ktf-bar-ink: #fff; }
.v-b .ktf-top { border-bottom: 0; }
.v-b .ktf-time { background: #ffc20e; color: #111; }
.v-b .ktf-time.kt-low { background: #c8231a; color: #fff; }
.v-b .ktf-progress { height: 6px; background: #333; }
.v-b .ktf-progress span { background: #ffc20e; }
.v-b .ktf-brand, .v-b .ktf-count strong { font-stretch: 75%; font-weight: 900; text-transform: uppercase; }
.v-b .ktf-q { font-weight: 800; font-stretch: 90%; }
.v-b .ktf-opt { border-width: 3px; border-color: #111; }
.v-b .ktf-opt.kt-picked { background: #fff1b8; border-color: #111; }
.v-b .ktf-opt.kt-picked .ktf-l { background: #111; border-color: #111; color: #ffc20e; }
.v-b .ktf-opt.kt-right { background: #e7f4ec; border-color: #2e7d4f; }
.v-b .ktf-opt.kt-right .ktf-l { background: #2e7d4f; border-color: #2e7d4f; color: #fff; }
.v-b .ktf-opt.kt-wrong { background: #fbeae8; border-color: #b3261e; }
.v-b .ktf-opt.kt-wrong .ktf-l { background: #b3261e; border-color: #b3261e; color: #fff; }
.v-b .ktf-main { background: #111; color: #ffc20e; text-transform: uppercase; letter-spacing: .04em; font-weight: 800; }
.v-b .ktf-title { font-stretch: 70%; font-weight: 900; text-transform: uppercase; }
.v-b .ktf-cta { background: #ffc20e; color: #111; }
.v-b .ktf-cta .ktf-main { background: #111; color: #ffc20e; }


/* c: Soft Bauhaus. Ink outlines, pastel states, buttons that press. */
.v-c .ktf { --b: 2.5px solid var(--ink); background: var(--bg); }
.v-c .ktf-top { background: #fbf7ef; border-bottom: var(--b); }
.v-c .ktf-brand, .v-c .ktf-count strong { font-family: var(--head); font-weight: 800; letter-spacing: -0.04em; }
.v-c .ktf-time { background: #ffd45c; border: 2px solid var(--ink); font-family: 'DM Mono', monospace; }
.v-c .ktf-time.kt-low { background: #ff7a59; color: var(--ink); }
.v-c .ktf-progress { height: 8px; background: #ece4d6; border-bottom: var(--b); }
.v-c .ktf-progress span { background: #ff7a59; }
.v-c .ktf-sec { font-family: 'DM Mono', monospace; color: var(--ink); }
.v-c .ktf-q { font: 700 clamp(1.3rem, 1rem + 1.6vw, 1.9rem)/1.2 var(--head); letter-spacing: -0.03em; }
.v-c .ktf-trap { border: var(--b); border-left-width: 8px; border-radius: 12px; background: #c7b8ff; }
.v-c .ktf-opt { border: var(--b); border-radius: 14px; background: #fbf7ef; box-shadow: 4px 4px 0 var(--ink); transition: transform .12s, box-shadow .12s, background-color .15s; }
.v-c .ktf-opt:hover:not(:disabled) { border-color: var(--ink); background: #fff3c9; transform: translate(-1px, -1px); box-shadow: 5px 5px 0 var(--ink); }
.v-c .ktf-opt:active:not(:disabled) { transform: translate(4px, 4px); box-shadow: 0 0 0 var(--ink); }
.v-c .ktf-l { border: 2px solid var(--ink); font-family: 'DM Mono', monospace; }
.v-c .ktf-opt.kt-picked { background: #ffd45c; border-color: var(--ink); }
.v-c .ktf-opt.kt-picked .ktf-l { background: var(--ink); color: #ffd45c; border-color: var(--ink); }
.v-c .ktf-opt.kt-right { background: #9fe0bf; border-color: var(--ink); color: var(--ink); }
.v-c .ktf-opt.kt-right .ktf-l { background: var(--ink); border-color: var(--ink); }
.v-c .ktf-opt.kt-wrong { background: #ffb3a1; border-color: var(--ink); color: var(--ink); }
.v-c .ktf-opt.kt-wrong .ktf-l { background: var(--ink); border-color: var(--ink); }
.v-c .ktf-explain { border: var(--b); border-left-width: 8px; border-left-color: #2e9a63; border-radius: 14px; background: #fbf7ef; box-shadow: 4px 4px 0 var(--ink); }
.v-c .ktf-explain.kt-no { border-left-color: #e8553d; }
.v-c .ktf-verdict { font-family: var(--head); letter-spacing: -0.03em; color: var(--ink); }
.v-c .kt-no .ktf-verdict { color: var(--ink); }
.v-c .ktf-act { background: #fbf7ef; border-top: var(--b); }
.v-c .ktf-main { border: var(--b); border-radius: 14px; background: #ffd45c; color: var(--ink); box-shadow: 4px 4px 0 var(--ink); }
.v-c .ktf-main:active:not(:disabled) { transform: translate(4px, 4px); box-shadow: 0 0 0 var(--ink); }
.v-c .ktf-sub { border: var(--b); border-radius: 14px; }
.v-c .ktf-facts li { border: var(--b); border-radius: 14px; background: #fbf7ef; }
.v-c .ktf-facts li:nth-child(1) { background: #ffd45c; } .v-c .ktf-facts li:nth-child(2) { background: #8cb8ff; } .v-c .ktf-facts li:nth-child(3) { background: #9fe0bf; }
.v-c .ktf-kicker { font-family: 'DM Mono', monospace; color: var(--ink); }
.v-c .ktf-title { font-weight: 800; letter-spacing: -0.04em; }
.v-c .ktf-score { background: conic-gradient(#ff7a59 calc(var(--p) * 1%), #ece4d6 0); border: var(--b); }
.v-c .ktf-score span { border: var(--b); }
.v-c .ktf-cta { border: var(--b); border-radius: 20px; background: #c7b8ff; color: var(--ink); box-shadow: 6px 6px 0 var(--ink); }
.v-c .ktf-cta .ktf-main { background: #ffd45c; color: var(--ink); }
.v-c .ktf-grid button { border: 2px solid var(--ink); }
.v-c .ktf-grid .kt-done { background: #9fe0bf; }
.v-c .kt-btn { border: var(--b); background: #ffd45c; color: var(--ink); box-shadow: 4px 4px 0 var(--ink); }

/* d: the previous c, playful. Soft rounded buttons that press down. */
.v-d .ktf-opt { border-radius: 18px; box-shadow: 0 3px 0 var(--line); }
.v-d .ktf-opt:active:not(:disabled) { transform: translateY(2px); box-shadow: 0 1px 0 var(--line); }
.v-d .ktf-main { border-radius: 999px; box-shadow: 0 4px 0 #5e2a12; }
.v-d .ktf-main:active:not(:disabled) { transform: translateY(3px); box-shadow: 0 1px 0 #5e2a12; }
.v-d .ktf-sub { border-radius: 999px; }
.v-d .ktf-facts li, .v-d .ktf-explain { border-radius: 20px; }
.v-d .ktf-cta { border-radius: 26px; background: #2a1f16; }