/* ============================================================
   HOUSE PRICE INSIGHTS — STYLESHEET
   ------------------------------------------------------------
   A left-anchored technical report. One sans family (Archivo)
   carries all text; JetBrains Mono is reserved for the report's
   actual numeric output (stat figures), not for labels.

   Two accent colours run through the page with real meaning:
     --color-a  → Model A (area-only regression)
     --color-b  → Model B (12-predictor regression)

   The one deliberate flourish is in the hero: a CSS-drawn
   scatter plot with a regression line that draws itself in,
   echoing the project's own Figure 3.2. Everything else is
   quiet — spacing and hairline rules do the organising, not
   boxes or shadows.
   ============================================================ */

/* ---------- Fonts ---------- */
@import url('https://fonts.googleapis.com/css2?family=Archivo:wght@500;600;700&family=JetBrains+Mono:wght@500;600;700&display=swap');

/* ---------- Design tokens ---------- */
:root {
  --font-sans: 'Archivo', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --color-paper: #eff2f5;
  --color-paper-raised: #e3e8ed;
  --color-ink: #14181f;
  --color-ink-soft: #3d4857;
  --color-ink-faint: #5a6672;
  --color-line: #d7dce2;
  --color-line-strong: #b8c2cc;

  --color-a: #2a4fd6;        /* Model A — area only */
  --color-a-deep: #1f3ba8;
  --color-a-light: #9db4f5;  /* for use on dark backgrounds */
  --color-a-soft: #dce3f9;

  --color-b: #cc6b12;        /* Model B — all 12 predictors */
  --color-b-text: #a85a10;   /* AA-safe for body text/links */
  --color-b-light: #f0ac5c;  /* for use on dark backgrounds */
  --color-b-soft: #f5e3ce;

  --content-width: 1100px;
  --radius: 4px;
  --ease: cubic-bezier(.4, 0, .2, 1);
}

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
[id] { scroll-margin-top: 88px; }
img, svg { display: block; max-width: 100%; height: auto; }
a { color: inherit; text-decoration: none; }
ul, ol { list-style-position: outside; padding-left: 1.2rem; }
table { border-collapse: collapse; }

/* ---------- Base typography ---------- */
body {
  font-family: var(--font-sans);
  background: var(--color-paper);
  color: var(--color-ink);
  font-size: 17px;
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}
main { flex: 1 0 auto; }
footer { flex-shrink: 0; }

h1, h2, h3, h4 {
  font-family: var(--font-sans);
  font-weight: 700;
  color: var(--color-ink);
  line-height: 1.2;
}
p { margin-bottom: 1.1rem; }
p:last-child { margin-bottom: 0; }
ul, ol { margin-bottom: 1.25rem; }
li { margin-bottom: .5rem; line-height: 1.6; }
li:last-child { margin-bottom: 0; }
li::marker { color: var(--color-a); }
strong { font-weight: 600; }

code {
  font-family: var(--font-mono);
  font-size: .88em;
  background: var(--color-a-soft);
  color: var(--color-a-deep);
  padding: .15em .4em;
  border-radius: 3px;
}
var { font-family: var(--font-mono); font-style: italic; color: var(--color-ink-soft); }

/* ---------- Accessibility ---------- */
:focus-visible { outline: 2px solid var(--color-a); outline-offset: 3px; }
::selection { background: var(--color-a-soft); color: var(--color-ink); }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .01ms !important;
    transition-duration: .01ms !important;
  }
}

/* ---------- Shared layout: left-anchored containers ---------- */
.navdiv, .hero-content, .dataset-preview, .dataset-insights,
.project-overview-div, .key-finding-div, .feature-analysis-div,
.model-evaluation-div, .explore-findings-div, .limitations-div,
.conclusion-div, .footer-div {
  max-width: var(--content-width);
  margin-left: clamp(1.25rem, 6vw, 6rem);
  margin-right: 1.5rem;
}
.hero-content,
.project-overview-div,
.conclusion-div { max-width: 640px; }
.key-finding-div,
.limitations-div { max-width: 760px; }

/* Section heading + intro paragraph, shared across the page */
section h2 {
  font-size: clamp(1.55rem, 1.35rem + 1vw, 2.2rem);
  margin-bottom: .75rem;
}
h2 + p {
  color: var(--color-ink-soft);
  font-size: 1.03rem;
  max-width: 62ch;
  margin-bottom: 2.25rem;
}

/* ---------- Shared component: report sub-sections ---------- */
.dataset-block, .analysis-block, .evaluation-block,
.explore-block, .limitations-block {
  margin-top: 3rem;
  padding-top: 3rem;
  border-top: 1px solid var(--color-line);
}
.dataset-block:first-of-type, .analysis-block:first-of-type,
.evaluation-block:first-of-type, .explore-block:first-of-type,
.limitations-block:first-of-type {
  border-top: none;
  padding-top: 0;
  margin-top: 2.5rem;
}
.dataset-block h3, .analysis-block h3, .evaluation-block h3,
.explore-block h3, .limitations-block h3 {
  font-size: clamp(1.1rem, 1.02rem + .4vw, 1.35rem);
  margin-bottom: .9rem;
}
.conclusion-div article {
  margin-top: 2.5rem;
  padding-top: 2.5rem;
  border-top: 1px solid var(--color-line);
}
.conclusion-div article:first-of-type { border-top: none; padding-top: 0; margin-top: 2rem; }

/* ---------- Shared component: tables ---------- */
table {
  width: 100%;
  margin: 1.75rem 0 2.25rem;
  font-size: .93rem;
  font-variant-numeric: tabular-nums;
}
caption {
  caption-side: top;
  text-align: left;
  font-size: .82rem;
  font-weight: 500;
  color: var(--color-ink-faint);
  margin-bottom: .75rem;
}
thead th {
  text-align: left;
  font-size: .82rem;
  font-weight: 600;
  color: var(--color-ink-soft);
  padding: .6rem .9rem;
  border-bottom: 2px solid var(--color-ink);
}
tbody th[scope="row"] { text-align: left; font-weight: 600; }
tbody td, tbody th { padding: .6rem .9rem; border-bottom: 1px solid var(--color-line); }
tbody tr:hover { background: var(--color-paper-raised); }

/* ---------- Shared component: figures ---------- */
figure { margin: 2rem 0; }
figure img { width: 100%; border: 1px solid var(--color-line); background: var(--color-paper-raised); }
figcaption { margin-top: .75rem; font-size: .85rem; color: var(--color-ink-faint); line-height: 1.5; }

/* ============================================================
   HEADER & NAVIGATION
   ============================================================ */
header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(239, 242, 245, .9);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-line);
}
.navdiv {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
  padding-block: 1.1rem;
}
.logo { font-weight: 700; font-size: .98rem; letter-spacing: .01em; color: var(--color-ink); }
.logo:hover { color: var(--color-a); }
.navdiv ul {
  display: flex;
  list-style: none;
  flex-wrap: wrap;
  gap: .5rem 1.6rem;
  padding: 0;
}
.navdiv ul a {
  display: inline-block;
  font-size: .92rem;
  font-weight: 500;
  color: var(--color-ink-soft);
  padding-bottom: .2rem;
  border-bottom: 2px solid transparent;
  transition: color .2s var(--ease), border-color .2s var(--ease);
}
.navdiv ul a:hover, .navdiv ul a:focus-visible { color: var(--color-ink); border-color: var(--color-a); }

/* ============================================================
   HOME — HERO
   ============================================================ */
.hero {
  position: relative;
  background: var(--color-paper);
  border-bottom: 1px solid var(--color-line);
  padding: clamp(3.5rem, 8vw, 6rem) 0 clamp(3rem, 6vw, 4.5rem);
}
.hero-content > p:first-of-type {
  font-size: 1rem;
  color: var(--color-ink-soft);
  margin-bottom: .6rem;
}
.hero-content h1 {
  font-size: clamp(2.1rem, 1.5rem + 3vw, 3.4rem);
  line-height: 1.1;
  letter-spacing: -.01em;
  margin-bottom: 1.2rem;
}
.hero-content > p:nth-of-type(2) {
  font-size: 1.1rem;
  color: var(--color-ink-soft);
  max-width: 50ch;
  margin-bottom: 2.1rem;
}
.hero-content a {
  display: inline-flex;
  align-items: center;
  padding: .85rem 1.6rem;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: .95rem;
  margin: .3rem .7rem .3rem 0;
  transition: transform .2s var(--ease), box-shadow .2s var(--ease), background .2s var(--ease), border-color .2s var(--ease);
}
.explore-insight { background: var(--color-a); color: var(--color-paper); border: 1.5px solid var(--color-a); }
.explore-insight:hover { background: var(--color-a-deep); border-color: var(--color-a-deep); transform: translateY(-2px); box-shadow: 0 10px 22px -8px rgba(42, 79, 214, .4); }
.model-results { background: transparent; color: var(--color-ink); border: 1.5px solid var(--color-line-strong); }
.model-results:hover { border-color: var(--color-ink); background: var(--color-paper-raised); transform: translateY(-2px); }

/* Hero scatter + regression-line motif — desktop only */
@media (min-width: 1180px) {
  .hero { min-height: 480px; overflow: hidden; }
  .hero::before, .hero::after {
    content: "";
    position: absolute;
    top: 15%;
    right: 7%;
    width: 300px;
    height: 300px;
  }
  .hero::before {
    background-image:
      radial-gradient(circle 4px at 8% 90%, var(--color-a) 97%, transparent),
      radial-gradient(circle 5px at 15% 79%, var(--color-a) 97%, transparent),
      radial-gradient(circle 4px at 21% 68%, var(--color-a) 97%, transparent),
      radial-gradient(circle 5px at 29% 73%, var(--color-a) 97%, transparent),
      radial-gradient(circle 4px at 37% 57%, var(--color-a) 97%, transparent),
      radial-gradient(circle 5px at 45% 61%, var(--color-a) 97%, transparent),
      radial-gradient(circle 4px at 52% 45%, var(--color-a) 97%, transparent),
      radial-gradient(circle 5px at 60% 49%, var(--color-a) 97%, transparent),
      radial-gradient(circle 4px at 68% 33%, var(--color-a) 97%, transparent),
      radial-gradient(circle 5px at 76% 37%, var(--color-a) 97%, transparent),
      radial-gradient(circle 4px at 84% 20%, var(--color-a) 97%, transparent),
      radial-gradient(circle 5px at 92% 13%, var(--color-a) 97%, transparent);
    opacity: .3;
  }
  .hero::after {
    height: 2px;
    top: calc(15% + 150px);
    background: var(--color-a);
    opacity: .55;
    transform-origin: center;
    animation: draw-trendline 1.3s var(--ease) .3s both;
  }
}
@keyframes draw-trendline {
  from { transform: rotate(-30deg) scaleX(0); }
  to   { transform: rotate(-30deg) scaleX(1); }
}
@media (prefers-reduced-motion: reduce) {
  .hero::after { animation: none; transform: rotate(-30deg) scaleX(1); }
}

/* ============================================================
   DATASET PREVIEW
   ============================================================ */
.dataset-preview { padding: clamp(2.25rem, 5vw, 3.25rem) 0; background: var(--color-paper-raised); }
.dataset-Preview-div { margin-top: 1rem; }
.dataset-Preview-div dl { display: flex; flex-wrap: wrap; }
.dataset-Preview-div dl > div { flex: 1 1 150px; padding: 0 1.75rem; border-left: 1px solid var(--color-line-strong); }
.dataset-Preview-div dl > div:first-child { padding-left: 0; border-left: none; }
.dataset-Preview-div dt { font-family: var(--font-mono); font-weight: 700; font-size: clamp(1.9rem, 1.5rem + 1.2vw, 2.6rem); color: var(--color-a); line-height: 1; margin-bottom: .4rem; }
.dataset-Preview-div dd { font-size: .88rem; color: var(--color-ink-soft); }

/* ============================================================
   PROJECT OVERVIEW
   ============================================================ */
.project-overview { padding: clamp(3rem, 6vw, 4.5rem) 0; }
.project-overview-div p { font-size: 1.02rem; color: var(--color-ink-soft); max-width: 62ch; }

/* ============================================================
   KEY FINDING (dark band)
   ============================================================ */
.key-finding { background: var(--color-ink); color: var(--color-paper); padding: clamp(3rem, 6vw, 4.5rem) 0; }
.key-finding-div h2 { color: var(--color-paper); }
.key-finding-div h2 + p { color: rgba(239, 242, 245, .78); }
.key-finding-div dl { display: flex; flex-wrap: wrap; margin: 2rem 0; }
.key-finding-div dl > div { flex: 1 1 180px; padding: 0 2rem; border-left: 1px solid rgba(239, 242, 245, .25); }
.key-finding-div dl > div:first-child { padding-left: 0; border-left: none; }
.key-finding-div dt { font-family: var(--font-mono); font-weight: 700; font-size: clamp(2rem, 1.6rem + 1.4vw, 2.85rem); line-height: 1; margin-bottom: .5rem; color: var(--color-a-light); }
.key-finding-div dl > div:nth-child(2) dt, .key-finding-div dl > div:nth-child(3) dt { color: var(--color-b-light); }
.key-finding-div dd { font-size: .86rem; color: rgba(239, 242, 245, .72); }
.key-finding-div > p:last-child { margin-top: 1.5rem; font-size: .92rem; color: rgba(239, 242, 245, .62); max-width: 58ch; }

/* ============================================================
   DATASET & PRICE INSIGHTS
   ============================================================ */
.dataset-insights { padding: clamp(3rem, 6vw, 5rem) 0; }

/* ============================================================
   FEATURE ANALYSIS
   ============================================================ */
.feature-analysis { padding: clamp(3rem, 6vw, 5rem) 0; background: var(--color-paper-raised); }

/* ============================================================
   MODEL EVALUATION
   ============================================================ */
.model-evaluation { padding: clamp(3rem, 6vw, 5rem) 0; }
.evaluation-block ul { margin-top: 1rem; }

/* ============================================================
   EXPLORE FINDINGS
   ============================================================ */
.explore-findings { padding: clamp(3rem, 6vw, 5rem) 0; background: var(--color-paper-raised); }

.insights-metrics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 2.25rem 2rem;
  margin-top: 1.5rem;
}
.insights-metrics-grid > div { border-top: 3px solid var(--color-a); padding-top: 1rem; }
.insights-metrics-grid > div:nth-child(even) { border-top-color: var(--color-b); }
.insights-metrics-grid dt { font-family: var(--font-mono); font-weight: 700; font-size: clamp(1.75rem, 1.5rem + .8vw, 2.25rem); color: var(--color-a); margin-bottom: .5rem; }
.insights-metrics-grid > div:nth-child(even) dt { color: var(--color-b); }
.insights-metrics-grid dd:first-of-type { color: var(--color-ink); font-weight: 600; margin-bottom: .35rem; }
.insights-metrics-grid dd:last-of-type { color: var(--color-ink-soft); font-size: .92rem; line-height: 1.55; }

.interactive-widget-box {
  margin-top: 1.5rem;
  padding: 2.25rem 1.5rem;
  border: 1.5px dashed var(--color-line-strong);
  text-align: center;
}
.interactive-widget-box p { color: var(--color-ink-faint); max-width: 44ch; margin-inline: auto; }

/* ============================================================
   LIMITATIONS
   ============================================================ */
.limitations { padding: clamp(3rem, 6vw, 5rem) 0; }
.important-note-box {
  margin-top: 3rem;
  padding: 1.5rem 1.75rem;
  background: var(--color-a-soft);
  border-left: 3px solid var(--color-a);
}
.important-note-box h3 { font-size: 1rem; margin-bottom: .5rem; }
.important-note-box p { color: var(--color-ink-soft); }

/* ============================================================
   CONCLUSION AND FUTURE SCOPE
   ============================================================ */
.conclusion { padding: clamp(3rem, 6vw, 5rem) 0; background: var(--color-paper-raised); }
.conclusion-div p { color: var(--color-ink-soft); max-width: 66ch; }

/* ============================================================
   FOOTER
   ============================================================ */
footer { background: var(--color-ink); color: var(--color-paper); text-align: center; }
.footer-div { padding: 3.25rem 0 2.25rem; }
.footer-div h2 { color: var(--color-paper); font-size: 1.3rem; margin-bottom: .75rem; }
.footer-div p { max-width: none; color: rgba(239, 242, 245, .72); font-size: .92rem; margin-bottom: .4rem; }
.footer-div p:last-child { margin-top: 1.25rem; margin-bottom: 0; }
.footer-div a { color: var(--color-a-light); font-weight: 600; border-bottom: 1px solid transparent; transition: border-color .2s var(--ease); }
.footer-div a:hover { border-color: var(--color-a-light); }
.footer-div p:last-child a::before { content: "\2191  "; }

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 700px) {
  table { display: block; overflow-x: auto; -webkit-overflow-scrolling: touch; white-space: nowrap; }
}

@media (max-width: 640px) {
  .navdiv { flex-direction: column; align-items: flex-start; gap: .75rem; padding-block: 1rem; }
  .navdiv ul { gap: .5rem 1.25rem; }

  .dataset-Preview-div dl, .key-finding-div dl { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem; }
  .dataset-Preview-div dl > div, .key-finding-div dl > div { border-left: none; padding: 0; }
}

@media (max-width: 480px) {
  .hero-content a { display: flex; width: 100%; justify-content: center; margin-right: 0; }
}


/* INTERACTIVE JAVASCRIPT TOOLS */

.interactive-widget-box {
    text-align: left;
}

.interactive-tools {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 2rem;
    text-align: left;
}

.interactive-tool {
    border-top: none;
    padding-top: 1.5rem;
}

.interactive-tool h4 {
    font-size: 1.1rem;
    margin-bottom: 0.8rem;
}

.interactive-tool label {
    display: block;
    margin: 1rem 0 0.4rem;
    font-weight: 600;
}

.interactive-tool select,
.interactive-tool input {
    display: block;
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--color-line-strong);
    border-radius: var(--radius);
    background: var(--color-paper);
    color: var(--color-ink);
    font: inherit;
}

.interactive-tool button {
    margin-top: 1rem;
    padding: 0.75rem 1.2rem;
    border: none;
    border-radius: var(--radius);
    background: var(--color-a);
    color: white;
    font: inherit;
    font-weight: 600;
    cursor: pointer;
}

.interactive-tool button:hover {
    background: var(--color-a-deep);
}

.interactive-result {
    margin-top: 1.25rem;
    padding: 1rem;
    border: 1px solid var(--color-line);
    background: var(--color-paper);
}

.interactive-result p {
    text-align: left;
    margin-bottom: 0.7rem;
    color: var(--color-ink-soft);
}

.interactive-result p:last-child {
    margin-bottom: 0;
}