/* Rank Increase Simulator. Visual language matches dylan-costa.github.io:
   dark editorial look, Fraunces display type, Inter for structure, teal accent. */

@import url('https://fonts.googleapis.com/css2?family=Fraunces:opsz,wght@9..144,400;9..144,600;9..144,700&family=Inter:wght@400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap');

:root {
  --bg: #0b0f14;
  --bg-alt: #121822;
  --bg-raised: #161d29;
  --bg-input: #0e131a;
  --border: #232b38;
  --border-strong: #33404f;
  --text: #e9e7e1;
  --text-dim: #99a3b0;
  --accent: #5eead4;
  --accent-soft: rgba(94, 234, 212, 0.12);
  --accent-ink: #0b0f14;
  --warn: #fbbf24;
  --warn-soft: rgba(251, 191, 36, 0.12);
  --danger: #f87171;
  --rank0: #5eead4;
  --rank1: #60a5fa;
  --rank2: #c084fc;
  --rank3: #f472b6;
  --rank4: #fb923c;
  --rank-unknown: #64748b;
  --mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, monospace;
}

* { box-sizing: border-box; }

html {
  background-color: var(--bg);
  background-image: url('../assets/bg-math.svg');
  background-repeat: no-repeat;
  background-position: top center;
  background-size: cover;
  background-attachment: fixed;
  min-height: 100%;
  scroll-behavior: smooth;
}

body {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem 4rem;
  background: transparent;
  color: var(--text);
  font-family: 'Inter', sans-serif;
  line-height: 1.65;
}

h1 {
  font-family: 'Fraunces', serif;
  font-weight: 600;
  font-size: 2.8rem;
  letter-spacing: -0.01em;
  margin: 0.6rem 0 1rem;
}

h2 {
  font-weight: 600;
  font-size: 1.25rem;
  margin: 0;
}

h3 {
  font-weight: 600;
  font-size: 1.05rem;
  color: var(--accent);
  margin: 1.5rem 0 0.5rem;
}

a { color: var(--accent); text-decoration: none; border-bottom: 1px solid transparent; }
a:hover { border-bottom-color: currentColor; }

code {
  font-family: var(--mono);
  font-size: 0.88em;
  background: var(--bg-raised);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0.05em 0.35em;
}

.eyebrow {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
}

/* ---- Top navigation (same as the main site) ---------------------------- */

.topnav {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 0.25rem;
  padding: 1.75rem 0;
  border-bottom: 1px solid var(--border);
  margin-bottom: 1rem;
  flex-wrap: wrap;
}
.topnav::before {
  content: "Dylan Costa";
  font-family: 'Fraunces', serif;
  font-weight: 600;
  font-size: 1.15rem;
  color: var(--text);
  margin-right: auto;
}
.topnav a, .dropbtn {
  color: var(--text-dim);
  padding: 0.5rem 0.9rem;
  font-family: 'Inter', sans-serif;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  background: none;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
}
.topnav a:hover, .dropdown:hover .dropbtn, .topnav a.active { color: var(--accent); border-bottom-color: transparent; }
.dropdown { position: relative; }
.dropdown-content {
  display: none;
  position: absolute;
  top: 100%;
  right: 0;
  background: var(--bg-raised);
  border: 1px solid var(--border);
  border-radius: 8px;
  min-width: 190px;
  padding: 0.4rem;
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.45);
  z-index: 10;
}
.dropdown-content a {
  display: block;
  padding: 0.6rem 0.7rem;
  border-radius: 5px;
  text-transform: none;
  letter-spacing: normal;
  font-weight: 500;
}
.dropdown-content a:hover { background: var(--accent-soft); }
.dropdown:hover .dropdown-content, .dropdown:focus-within .dropdown-content { display: block; }

/* ---- Intro --------------------------------------------------------------- */

.intro { padding: 2rem 0 0.5rem; }
.lead { color: var(--text-dim); font-size: 1.1rem; max-width: 70ch; line-height: 1.75; }
.lead .katex { color: var(--text); }

.explainer {
  max-width: 75ch;
  margin: 1rem 0 0;
  color: var(--text-dim);
}
.explainer summary {
  cursor: pointer;
  color: var(--accent);
  font-weight: 600;
  font-size: 0.95rem;
}
.explainer p { margin: 0.8rem 0; }
.explainer strong { color: var(--text); }

/* ---- Cards --------------------------------------------------------------- */

.card {
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 1.75rem 2rem;
  margin: 1.75rem 0;
  background: rgba(18, 24, 34, 0.92);
  backdrop-filter: blur(2px);
}

.step-head { display: flex; align-items: center; gap: 0.85rem; margin-bottom: 1.25rem; }
.step-num {
  display: inline-grid;
  place-items: center;
  width: 2rem;
  height: 2rem;
  border-radius: 50%;
  border: 1px solid var(--accent);
  color: var(--accent);
  font-weight: 700;
  font-size: 0.95rem;
  flex: none;
}

.hint { color: var(--text-dim); font-size: 0.88rem; margin: 0.5rem 0; }

/* ---- Equation input ------------------------------------------------------ */

.segmented {
  display: inline-flex;
  border: 1px solid var(--border-strong);
  border-radius: 999px;
  padding: 3px;
  margin-bottom: 1.25rem;
  background: var(--bg-input);
}
.segmented button {
  border: none;
  background: none;
  color: var(--text-dim);
  font: 600 0.85rem 'Inter', sans-serif;
  padding: 0.45rem 1.05rem;
  border-radius: 999px;
  cursor: pointer;
}
.segmented button[aria-selected="true"] { background: var(--accent); color: var(--accent-ink); }

.fill-eq {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.45rem 0.5rem;
  font-family: 'Fraunces', serif;
  font-size: 1.55rem;
  font-style: italic;
  padding: 1rem 1.25rem;
  border: 1px dashed var(--border-strong);
  border-radius: 12px;
  background: var(--bg-input);
}
.fill-eq[hidden] { display: none; }
.fill-eq .eqt { white-space: nowrap; }
.fill-eq sup { font-size: 0.6em; }

input.coef {
  font: 500 1.05rem var(--mono);
  font-style: normal;
  width: 4.2ch;
  min-width: 4.2ch;
  max-width: 100%;
  padding: 0.3rem 0.35rem;
  text-align: center;
  color: var(--text);
  background: var(--bg-raised);
  border: 1px solid var(--border-strong);
  border-radius: 7px;
}
input.coef::placeholder { color: #4b5563; }
input:focus-visible, button:focus-visible, summary:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}
input.invalid { border-color: var(--danger); box-shadow: 0 0 0 1px var(--danger); }

.text-entry { display: block; margin-top: 1.25rem; }
.text-entry > span { display: block; font-size: 0.9rem; color: var(--text-dim); margin-bottom: 0.4rem; }
#coeff-text {
  width: 100%;
  font: 500 1rem var(--mono);
  padding: 0.65rem 0.85rem;
  color: var(--text);
  background: var(--bg-input);
  border: 1px solid var(--border-strong);
  border-radius: 9px;
}

.examples { display: flex; flex-wrap: wrap; align-items: center; gap: 0.5rem; margin: 1.1rem 0 0.25rem; }
.examples-label { font-size: 0.85rem; color: var(--text-dim); margin-right: 0.25rem; }
.chip {
  font: 500 0.82rem 'Inter', sans-serif;
  color: var(--text);
  background: var(--bg-raised);
  border: 1px solid var(--border-strong);
  border-radius: 999px;
  padding: 0.3rem 0.8rem;
  cursor: pointer;
}
.chip:hover { border-color: var(--accent); color: var(--accent); }

/* ---- Buttons --------------------------------------------------------------- */

.actions { display: flex; flex-wrap: wrap; align-items: center; gap: 1rem; margin-top: 1.5rem; }

.btn-primary, .btn-ghost, .btn-pill {
  font: 600 0.92rem 'Inter', sans-serif;
  border-radius: 999px;
  padding: 0.7rem 1.5rem;
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease, opacity 0.15s;
}
.btn-primary { background: var(--accent); color: var(--accent-ink); border: 1px solid var(--accent); }
.btn-primary:hover:not(:disabled) { background: #99f6e4; }
.btn-primary:disabled { opacity: 0.45; cursor: not-allowed; }
.btn-primary .katex { color: inherit; }
.btn-ghost, .btn-pill { background: transparent; color: var(--accent); border: 1px solid var(--accent); }
.btn-ghost:hover, .btn-pill:hover { background: var(--accent-soft); }
a.btn-pill { display: inline-block; border-bottom: 1px solid var(--accent); }

.engine-status { font-size: 0.85rem; color: var(--text-dim); display: inline-flex; align-items: center; gap: 0.5rem; }
.engine-status::before {
  content: "";
  width: 0.55rem;
  height: 0.55rem;
  border-radius: 50%;
  background: var(--warn);
  animation: pulse 1.2s ease-in-out infinite;
}
.engine-status.ready::before { background: var(--accent); animation: none; }
.engine-status.failed::before { background: var(--danger); animation: none; }
@keyframes pulse { 50% { opacity: 0.3; } }

.error {
  color: var(--danger);
  background: rgba(248, 113, 113, 0.08);
  border: 1px solid rgba(248, 113, 113, 0.35);
  border-radius: 9px;
  padding: 0.6rem 0.9rem;
  margin: 1rem 0 0;
  font-size: 0.92rem;
}

/* ---- Curve display ------------------------------------------------------- */

.curve-head { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: baseline; gap: 0.5rem 1rem; }
.curve-eq {
  font-size: 1.3rem;
  margin: 0.9rem 0 0.4rem;
  padding: 0.85rem 1.1rem;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: 10px;
  overflow-x: auto;
  overflow-y: hidden;
}
.curve-eq .katex-display { margin: 0; }
.curve-note { font-size: 0.85rem; color: var(--text-dim); margin: 0.2rem 0 0; }

.facts {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 0.75rem 1.5rem;
  margin: 1.25rem 0 0.5rem;
}
.fact { min-width: 0; }
.fact dt {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-dim);
}
.fact dd { margin: 0.15rem 0 0; overflow-x: auto; overflow-y: hidden; white-space: nowrap; padding-bottom: 2px; }
.fact-sub { font-size: 0.88em; color: var(--text-dim); }
.fact-sub .katex { color: var(--text-dim); }

.mw {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 1.25rem 2rem;
  align-items: start;
  margin-top: 1.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
}
.rank-big { text-align: center; min-width: 7rem; }
.rank-big .num { font-family: 'Fraunces', serif; font-size: 3.6rem; font-weight: 600; line-height: 1; }
.rank-big .lbl { font-size: 0.72rem; font-weight: 600; letter-spacing: 0.12em; text-transform: uppercase; color: var(--text-dim); margin-top: 0.3rem; }
.mw-body { min-width: 0; }
.mw-group { font-size: 1.2rem; overflow-x: auto; overflow-y: hidden; }

.badge {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  padding: 0.15rem 0.6rem;
  border-radius: 999px;
  margin-top: 0.5rem;
  border: 1px solid currentColor;
  cursor: help;
}
.badge.proven { color: var(--accent); background: var(--accent-soft); }
.badge.bsd { color: var(--warn); background: var(--warn-soft); }
.badge.undetermined { color: var(--danger); }
.status-line { font-size: 0.85rem; color: var(--text-dim); margin: 0.35rem 0 0; }

.gens { list-style: none; padding: 0; margin: 0.75rem 0 0; }
.gens li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.25rem 1rem;
  padding: 0.45rem 0;
  border-bottom: 1px solid var(--border);
  overflow-x: auto;
}
.gens li:last-child { border-bottom: none; }
.gens .h { font-size: 0.82rem; color: var(--text-dim); white-space: nowrap; }
.gens-title { font-size: 0.78rem; font-weight: 600; letter-spacing: 0.1em; text-transform: uppercase; color: var(--text-dim); margin-top: 1rem; }

.links { display: flex; flex-wrap: wrap; gap: 0.75rem; margin-top: 1.25rem; }

/* ---- Step 2 -------------------------------------------------------------- */

.rank-picker { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 0.75rem; }
.rank-picker button {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.1rem;
  padding: 1rem 0.5rem;
  background: var(--bg-input);
  color: var(--text);
  border: 1px solid var(--border-strong);
  border-radius: 12px;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
}
.rank-picker button:hover { border-color: var(--accent); }
.rank-picker button[aria-checked="true"] { border-color: var(--accent); background: var(--accent-soft); box-shadow: 0 0 0 1px var(--accent); }
.rank-picker .rk { font-family: 'Fraunces', serif; font-size: 2rem; font-weight: 600; line-height: 1.1; }
.rank-picker .rk-sub { font-size: 0.75rem; color: var(--text-dim); }

.range-row { display: flex; flex-wrap: wrap; align-items: center; gap: 0.6rem 0.8rem; margin-top: 1.5rem; }
#range-x {
  width: 8rem;
  font: 500 1rem var(--mono);
  padding: 0.5rem 0.7rem;
  color: var(--text);
  background: var(--bg-input);
  border: 1px solid var(--border-strong);
  border-radius: 8px;
}

/* ---- Search panel -------------------------------------------------------- */

.search-top { display: flex; justify-content: space-between; align-items: flex-start; gap: 1rem; }
.progress-text { font-size: 0.95rem; margin-top: 0.2rem; font-variant-numeric: tabular-nums; }
.progress { height: 6px; background: var(--bg-input); border-radius: 999px; margin: 1rem 0 1.25rem; overflow: hidden; }
.progress-fill { height: 100%; width: 0; background: var(--accent); border-radius: 999px; transition: width 0.2s ease; }

.tally-title { font-size: 0.78rem; font-weight: 600; letter-spacing: 0.1em; text-transform: uppercase; color: var(--text-dim); margin-bottom: 0.5rem; }
.tally { display: grid; grid-template-columns: auto 1fr auto; gap: 0.35rem 0.75rem; align-items: center; font-variant-numeric: tabular-nums; }
.tally .t-lbl { font-size: 0.85rem; white-space: nowrap; }
.tally .t-bar { height: 12px; background: var(--bg-input); border-radius: 3px; overflow: hidden; }
.tally .t-fill { height: 100%; width: 0; border-radius: 3px; transition: width 0.2s ease; }
.tally .t-num { font-size: 0.85rem; color: var(--text-dim); text-align: right; min-width: 6.5rem; }

.log { margin-top: 1.25rem; }
.log summary { cursor: pointer; color: var(--accent); font-weight: 600; font-size: 0.9rem; }
.log-scroll { max-height: 340px; overflow: auto; margin-top: 0.75rem; border: 1px solid var(--border); border-radius: 10px; }
.log table { width: 100%; border-collapse: collapse; font-size: 0.85rem; font-variant-numeric: tabular-nums; }
.log th, .log td { padding: 0.4rem 0.75rem; text-align: left; border-bottom: 1px solid var(--border); white-space: nowrap; }
.log th { position: sticky; top: 0; background: var(--bg-raised); color: var(--text-dim); font-weight: 600; }
.log td.mono { font-family: var(--mono); }
.log tr.hit td { background: var(--accent-soft); color: var(--accent); font-weight: 600; }
.log tr.bad td { color: var(--danger); }
.rank-dot { display: inline-block; width: 0.55rem; height: 0.55rem; border-radius: 50%; margin-right: 0.4rem; }

/* ---- Results ------------------------------------------------------------- */

.result-card { border-color: var(--accent); box-shadow: 0 0 0 1px rgba(94, 234, 212, 0.25), 0 24px 60px rgba(0, 0, 0, 0.35); }
.result-card.none { border-color: var(--warn); box-shadow: none; }
.result-headline { font-family: 'Fraunces', serif; font-size: 1.7rem; font-weight: 600; margin: 0.3rem 0 0; line-height: 1.3; }
.rank-change { font-size: 0.95rem; color: var(--text-dim); margin-top: 0.5rem; overflow-x: auto; overflow-y: hidden; }
.warn-box {
  font-size: 0.88rem;
  color: var(--warn);
  background: var(--warn-soft);
  border: 1px solid rgba(251, 191, 36, 0.35);
  border-radius: 9px;
  padding: 0.6rem 0.9rem;
  margin-top: 1rem;
}
.history { font-size: 0.88rem; color: var(--text-dim); margin-top: 1rem; }
.another {
  margin-top: 1.75rem;
  padding: 1.1rem 1.25rem;
  border: 1px solid rgba(94, 234, 212, 0.35);
  border-left: 3px solid var(--accent);
  border-radius: 10px;
  background: var(--accent-soft);
}
.another-q { font-weight: 600; font-size: 1.05rem; margin: 0; }
.another .actions { margin-top: 0.9rem; }

.site-footer { margin-top: 3rem; padding-top: 1.5rem; border-top: 1px solid var(--border); font-size: 0.85rem; color: var(--text-dim); }

/* ---- Small screens ------------------------------------------------------- */

@media (max-width: 680px) {
  body { padding: 0 1rem 3rem; }
  h1 { font-size: 2.1rem; }
  .card { padding: 1.25rem 1.1rem; border-radius: 14px; }
  .fill-eq { font-size: 1.25rem; padding: 0.85rem; }
  .curve-eq { font-size: 0.95rem; padding: 0.6rem 0.75rem; }
  .result-headline { font-size: 1.4rem; }
  .rank-picker { gap: 0.4rem; }
  .rank-picker button { padding: 0.75rem 0.25rem; }
  .rank-picker .rk-sub { display: none; }
  .mw { grid-template-columns: 1fr; }
  .rank-big { text-align: left; }
  .topnav { padding: 1rem 0; }
  .topnav::before { width: 100%; margin-bottom: 0.25rem; }
  .topnav a, .dropbtn { padding: 0.4rem 0.6rem; font-size: 0.72rem; }
}