/* Backsolved app — same visual language as the marketing site, deliberately.
   A customer who pays on backsolved.com and lands on app.backsolved.com should
   not feel handed off to a different product. Light paper, ink text, monospace
   for every number. No framework, no webfont, one file. */

:root {
  --paper: #FAF9F6;
  --paper-2: #F2F0EA;
  --card: #FFFFFF;
  --ink: #17161A;
  --ink-2: #3C3A42;
  --muted: #6E6B75;
  --rule: #E2DFD6;
  --rule-2: #CFCBBF;
  --ok: #1B6B4C;
  --ok-bg: #E8F2ED;
  --bad: #A93B24;
  --bad-bg: #FBEDE9;
  --accent: #1F3D7A;
  --accent-soft: #E9EDF6;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  --head-h: 56px;
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0; background: var(--paper); color: var(--ink);
  font-family: var(--sans); font-size: 16px; line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
.wrap { max-width: 860px; margin: 0 auto; padding: 0 20px; }
.centered { padding-top: 20vh; text-align: center; }

h1 { font-size: clamp(1.6rem, 4vw, 2.1rem); line-height: 1.15; letter-spacing: -0.02em; margin: 0 0 .4em; }
h2 { font-size: 1.2rem; letter-spacing: -0.015em; margin: 2em 0 .5em; }
h3 { font-size: 1rem; margin: 1.6em 0 .4em; }
p { margin: 0 0 1em; }
a { color: var(--accent); text-underline-offset: 2px; }
.lede { color: var(--ink-2); font-size: 1.05rem; }
.small { font-size: .87rem; }
.muted { color: var(--muted); }
.mono { font-family: var(--mono); }

/* ---------- header ---------- */
.app-head {
  height: var(--head-h); border-bottom: 1px solid var(--rule);
  background: var(--paper); position: sticky; top: 0; z-index: 30;
}
.app-head .wrap { height: 100%; display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.brand { display: inline-flex; align-items: center; gap: 8px; font-weight: 700; color: var(--ink); text-decoration: none; letter-spacing: -0.02em; }
/* `hidden` must actually hide. A class that sets `display: flex` outranks the
   user-agent rule for the hidden attribute, so `el.hidden = true` on a flex
   container does nothing — which is how two header navs ended up rendering
   side by side and pushing a 390px screen into horizontal scroll. */
[hidden] { display: none !important; }

.head-right { display: flex; align-items: center; gap: 16px; }
.access-pill {
  font-family: var(--mono); font-size: .72rem; letter-spacing: .04em;
  background: var(--ok-bg); color: var(--ok); padding: 3px 9px; border-radius: 20px; white-space: nowrap;
}
.access-pill.free { background: var(--paper-2); color: var(--muted); }

/* ---------- screens ---------- */
.screen { display: none; }
.screen.active { display: block; }
#screenAuth, #screenCases, #screenReport, #screenHistory { padding: 40px 0 80px; }

/* ---------- buttons / forms ---------- */
.btn {
  display: inline-block; padding: 12px 20px; border-radius: 7px; border: 1px solid var(--ink);
  background: var(--ink); color: var(--paper); font: inherit; font-weight: 600; font-size: .95rem;
  cursor: pointer; transition: transform .08s ease, opacity .15s ease;
}
.btn:hover:not(:disabled) { background: #000; transform: translateY(-1px); }
.btn:disabled { opacity: .45; cursor: default; }
.btn-sm { padding: 8px 14px; font-size: .87rem; }
.btn-ghost { background: transparent; color: var(--ink); border-color: var(--rule-2); }
.btn-ghost:hover:not(:disabled) { background: var(--paper-2); }
.btn-row { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; margin: 1.4em 0; }
.linkbtn {
  background: none; border: 0; padding: 0; font: inherit; font-size: inherit;
  color: var(--accent); cursor: pointer; text-decoration: underline; text-underline-offset: 2px;
}
.linkbtn:hover { color: var(--ink); }

label { display: block; font-weight: 600; font-size: .87rem; margin: 1.1em 0 .3em; }
input[type=email], input[type=password], textarea {
  width: 100%; padding: 11px 13px; border: 1px solid var(--rule-2); border-radius: 7px;
  background: var(--card); color: var(--ink); font: inherit; font-size: 1rem;
}
input:focus, textarea:focus { outline: 2px solid var(--accent); outline-offset: 1px; border-color: transparent; }
.auth-wrap { max-width: 420px; }
#authForm .btn { width: 100%; margin-top: 1.4em; }

.formnote {
  margin: 1em 0 0; padding: 10px 13px; border-radius: 7px; font-size: .89rem;
  background: var(--bad-bg); color: var(--bad); border: 1px solid #EFD3CB;
}
.formnote.ok { background: var(--ok-bg); color: var(--ok); border-color: #C9E2D6; }

/* ---------- cases ---------- */
.banner {
  display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap;
  background: var(--accent-soft); border: 1px solid #D5DCEC; border-radius: 10px;
  padding: 14px 18px; margin: 1.5em 0;
}
.case-grid { display: grid; gap: 16px; margin: 1.6em 0; }
@media (min-width: 700px) { .case-grid { grid-template-columns: 1fr 1fr; } }

.case-card {
  border: 1px solid var(--rule); border-radius: 10px; background: var(--card);
  padding: 20px; display: flex; flex-direction: column; gap: 8px;
}
.case-card.locked { background: var(--paper-2); border-style: dashed; }
.case-card h3 { margin: 0; font-size: 1.05rem; }
.case-card .tags { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 2px; }
.tag {
  font-family: var(--mono); font-size: .7rem; letter-spacing: .05em; text-transform: uppercase;
  padding: 3px 8px; border-radius: 20px; background: var(--paper-2); color: var(--muted);
}
.tag.free { background: var(--ok-bg); color: var(--ok); }
.tag.locked { background: var(--bad-bg); color: var(--bad); }
.case-card p { margin: 0; font-size: .9rem; color: var(--ink-2); }
.case-card .btn { align-self: flex-start; margin-top: 8px; }

.upsell {
  border: 1.5px solid var(--ink); border-radius: 12px; padding: 24px; margin-top: 2.5em; background: var(--card);
}
.upsell h2 { margin-top: 0; }

/* ---------- interview ---------- */
#screenCase.active { display: flex; }
.case-layout { display: flex; flex-direction: column; height: calc(100vh - var(--head-h)); width: 100%; }
.case-head { border-bottom: 1px solid var(--rule); background: var(--paper); flex: 0 0 auto; }
.case-head-row { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 10px 0; flex-wrap: wrap; }
.case-head-actions { display: flex; align-items: center; gap: 12px; }
.case-head strong { display: block; font-size: .95rem; }

.transcript { flex: 1 1 auto; overflow-y: auto; padding: 24px 0; -webkit-overflow-scrolling: touch; }
.turn { max-width: 860px; margin: 0 auto 18px; padding: 0 20px; display: flex; }
.turn .bubble {
  padding: 12px 16px; border-radius: 12px; max-width: 44em; white-space: pre-wrap; word-wrap: break-word;
}
.turn.interviewer .bubble { background: var(--card); border: 1px solid var(--rule); }
.turn.candidate { justify-content: flex-end; }
.turn.candidate .bubble { background: var(--ink); color: var(--paper); }
.turn .who {
  font-family: var(--mono); font-size: .68rem; letter-spacing: .08em; text-transform: uppercase;
  color: var(--muted); margin-bottom: 5px;
}
.thinking .bubble { color: var(--muted); font-style: italic; }

.composer { flex: 0 0 auto; border-top: 1px solid var(--rule); background: var(--paper); padding: 12px 0 10px; }
.composer form { display: flex; gap: 10px; align-items: flex-end; }
.composer textarea { resize: none; max-height: 180px; }
.composer-hint { margin: 6px 0 0; }

/* ---------- report ---------- */
.scorebar { display: grid; gap: 14px; margin: 1.4em 0; }
@media (min-width: 640px) { .scorebar { grid-template-columns: repeat(4, 1fr); } }
.score {
  border: 1px solid var(--rule); border-radius: 10px; background: var(--card); padding: 14px;
}
.score .n { font-family: var(--mono); font-size: 1.7rem; font-weight: 700; letter-spacing: -0.02em; }
.score .l { font-size: .78rem; color: var(--muted); line-height: 1.3; }

.check { background: var(--card); border: 1px solid var(--rule); border-radius: 10px; overflow: hidden; margin: 1.4em 0; }
.check-head {
  padding: 10px 16px; border-bottom: 1px solid var(--rule); background: var(--paper-2);
  font-family: var(--mono); font-size: .72rem; letter-spacing: .07em; text-transform: uppercase; color: var(--muted);
}
.check-body { padding: 6px 16px; }
.check-row { display: grid; grid-template-columns: 1fr auto; gap: 6px 14px; padding: 12px 0; border-bottom: 1px dashed var(--rule); }
.check-row:last-child { border-bottom: 0; }
.check-said { font-family: var(--mono); font-size: .9rem; overflow-x: auto; }
.check-note { grid-column: 1 / -1; font-size: .85rem; color: var(--muted); }
.check-note b { color: var(--bad); }
.check-note em { color: var(--ok); font-style: normal; font-weight: 650; }
.pill { font-family: var(--mono); font-size: .72rem; font-weight: 600; padding: 3px 9px; border-radius: 20px; white-space: nowrap; height: fit-content; }
.pill.ok { background: var(--ok-bg); color: var(--ok); }
.pill.bad { background: var(--bad-bg); color: var(--bad); }

table { border-collapse: collapse; width: 100%; font-size: .92rem; margin: 1.2em 0; }
th, td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--rule); vertical-align: top; }
th { font-size: .75rem; text-transform: uppercase; letter-spacing: .05em; color: var(--muted); font-weight: 650; }
.tbl-scroll { overflow-x: auto; }

.reveal { border-left: 3px solid var(--rule-2); padding: 2px 0 2px 18px; margin: 1.4em 0; color: var(--ink-2); }

.hist-row {
  display: flex; align-items: center; justify-content: space-between; gap: 14px; flex-wrap: wrap;
  padding: 14px 0; border-bottom: 1px solid var(--rule);
}
.hist-row .meta { font-size: .85rem; color: var(--muted); }

/* ---------- toast ---------- */
.toast {
  position: fixed; left: 50%; bottom: 24px; transform: translateX(-50%);
  background: var(--ink); color: var(--paper); padding: 12px 18px; border-radius: 8px;
  font-size: .9rem; z-index: 60; max-width: min(90vw, 34em); box-shadow: 0 8px 30px -10px rgba(0,0,0,.5);
}
.toast.bad { background: var(--bad); }

:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 3px; }
@media (prefers-reduced-motion: reduce) { * { transition: none !important; } }