/* =========================================================
   QSAR Lab Sp. z o.o. — stylesheet
   1. Tokens
   2. Reset and base
   3. Layout helpers
   4. Buttons
   5. Header and navigation
   6. Hero
   7. About
   8. Services
   9. Benefits and stats
   10. Contact
   11. Footer
   12. Motion and responsive
   ========================================================= */

/* ---------- 1. Tokens ---------- */
:root {
  --petrol:        #0b2230;
  --petrol-soft:   #12303f;
  --slate:         #4a5e6d;
  --slate-light:   #7d8f9b;
  --paper:         #f4f6f5;
  --paper-warm:    #eceff0;
  --white:         #ffffff;
  --verdigris:     #1f7a6b;
  --verdigris-dk:  #17604f;
  --amber:         #d98e2b;
  --line:          #d9e0e0;
  --line-dark:     rgba(255, 255, 255, 0.16);
  --danger:        #b3402c;

  --font-sans: "IBM Plex Sans", "Segoe UI", system-ui, -apple-system, Arial, sans-serif;
  --font-serif: "IBM Plex Serif", Georgia, "Times New Roman", serif;

  --step--1: 0.875rem;
  --step-0:  1rem;
  --step-1:  1.1875rem;
  --step-2:  1.4375rem;
  --step-3:  1.875rem;
  --step-4:  2.375rem;
  --step-5:  clamp(2.25rem, 1.4rem + 3.4vw, 3.5rem);

  --gap:     1.5rem;
  --gutter:  1.5rem;
  --radius:  4px;
  --radius-lg: 8px;
  --max:     1160px;
  --header-h: 74px;
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

/* ---------- 2. Reset and base ---------- */
*, *::before, *::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 12px);
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--petrol);
  font-family: var(--font-serif);
  font-size: var(--step-0);
  line-height: 1.68;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, .btn, .nav-list, label, input, select, textarea,
.stat-value, .plot-stat, .brand, .footer-heading, .contact-key {
  font-family: var(--font-sans);
}

h1, h2, h3, h4 {
  margin: 0 0 0.6em;
  line-height: 1.18;
  font-weight: 600;
  letter-spacing: -0.018em;
}

p { margin: 0 0 1.1em; max-width: 68ch; }
p:last-child { margin-bottom: 0; }

a { color: var(--verdigris-dk); text-decoration: none; }
a:hover { text-decoration: underline; }

img, svg { max-width: 100%; }
ul, ol { margin: 0; padding: 0; list-style: none; }

:focus-visible {
  outline: 2px solid var(--verdigris);
  outline-offset: 3px;
  border-radius: 2px;
}

.skip-link {
  position: absolute;
  left: 1rem;
  top: -100px;
  z-index: 200;
  padding: 0.7rem 1.1rem;
  background: var(--petrol);
  color: var(--white);
  font-family: var(--font-sans);
  border-radius: var(--radius);
  transition: top 0.2s var(--ease);
}
.skip-link:focus { top: 1rem; }

/* ---------- 3. Layout helpers ---------- */
.container {
  width: 100%;
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

.section { padding: clamp(3.5rem, 7vw, 6rem) 0; }
.section-alt { background: var(--paper-warm); border-block: 1px solid var(--line); }
.section-dark { background: var(--petrol); color: rgba(255, 255, 255, 0.82); }
.section-dark .section-title { color: var(--white); }
.section-dark a { color: #8fd3c3; }

.section-title {
  font-size: var(--step-4);
  max-width: 20ch;
}

.section-head { margin-bottom: clamp(2rem, 4vw, 3rem); }
.section-head .section-title { max-width: 24ch; }

.section-intro {
  color: var(--slate);
  font-size: var(--step-1);
  max-width: 60ch;
}

/* ---------- 4. Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.8rem 1.5rem;
  border: 1px solid transparent;
  border-radius: var(--radius);
  font-size: var(--step-0);
  font-weight: 500;
  letter-spacing: 0.005em;
  cursor: pointer;
  transition: background-color 0.18s var(--ease),
              border-color 0.18s var(--ease),
              color 0.18s var(--ease),
              transform 0.18s var(--ease);
}
.btn:hover { text-decoration: none; }
.btn:active { transform: translateY(1px); }

.btn-primary {
  background: var(--verdigris);
  color: var(--white);
}
.btn-primary:hover { background: var(--verdigris-dk); }

.btn-ghost {
  background: transparent;
  border-color: var(--slate-light);
  color: var(--petrol);
}
.btn-ghost:hover { border-color: var(--petrol); background: rgba(11, 34, 48, 0.05); }

.btn-sm { padding: 0.55rem 1.1rem; font-size: var(--step--1); }
.btn-block { width: 100%; }

/* ---------- 5. Header and navigation ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(244, 246, 245, 0.92);
  backdrop-filter: saturate(140%) blur(8px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.25s var(--ease), background-color 0.25s var(--ease);
}
.site-header.is-scrolled {
  border-bottom-color: var(--line);
  background: rgba(244, 246, 245, 0.97);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: var(--header-h);
}

.brand { display: flex; align-items: center; gap: 0.7rem; color: var(--petrol); }
.brand:hover { text-decoration: none; }

.brand-mark { width: 30px; height: 30px; flex: none; }
.brand-mark circle { fill: var(--petrol); }
.brand-mark .brand-mark-accent { fill: var(--verdigris); }
.brand-mark path { stroke: var(--petrol); stroke-width: 1.6; fill: none; }

.brand-text { display: flex; flex-direction: column; line-height: 1.15; }
.brand-name { font-weight: 600; font-size: var(--step-1); letter-spacing: -0.02em; }
.brand-legal { font-size: 0.72rem; color: var(--slate); font-family: var(--font-sans); }

.nav-toggle {
  display: none;
  align-items: center;
  gap: 0.55rem;
  padding: 0.5rem 0.75rem;
  background: transparent;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-family: var(--font-sans);
  font-size: var(--step--1);
  color: var(--petrol);
  cursor: pointer;
}
.nav-toggle-bars { display: grid; gap: 4px; width: 18px; }
.nav-toggle-bars span {
  display: block;
  height: 2px;
  background: var(--petrol);
  transition: transform 0.22s var(--ease), opacity 0.16s var(--ease);
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-bars span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bars span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

.primary-nav { display: flex; align-items: center; gap: 2rem; }
.nav-list { display: flex; align-items: center; gap: 1.75rem; }

.nav-list a {
  position: relative;
  padding: 0.35rem 0;
  color: var(--petrol);
  font-size: var(--step--1);
  font-weight: 500;
}
.nav-list a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 2px;
  background: var(--verdigris);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.22s var(--ease);
}
.nav-list a:hover { text-decoration: none; }
.nav-list a:hover::after,
.nav-list a.is-active::after { transform: scaleX(1); }

/* ---------- 6. Hero ---------- */
.hero {
  padding: clamp(3rem, 6vw, 5.5rem) 0 clamp(3.5rem, 7vw, 6rem);
  background:
    radial-gradient(60% 90% at 88% 8%, rgba(31, 122, 107, 0.09), transparent 70%),
    var(--paper);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: clamp(2rem, 5vw, 4rem);
  align-items: center;
}

.hero-title {
  font-size: var(--step-5);
  letter-spacing: -0.03em;
  max-width: 16ch;
  text-wrap: balance;
}

.hero-lead {
  font-size: var(--step-1);
  color: var(--slate);
  max-width: 52ch;
}

.hero-actions { display: flex; flex-wrap: wrap; gap: 0.75rem; margin: 1.8rem 0 2.2rem; }

.hero-facts {
  display: grid;
  gap: 0.55rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--line);
  font-size: var(--step--1);
  color: var(--slate);
}
.hero-facts li { padding-left: 1.4rem; position: relative; }
.hero-facts li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.62em;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--verdigris);
}

.hero-figure { margin: 0; }

.plot-frame {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 1.25rem 1.25rem 1rem;
}

.plot { display: block; width: 100%; height: auto; }
.plot-grid line { stroke: #eef1f1; stroke-width: 1; }
.plot-axis line { stroke: #c4cfcf; stroke-width: 1; }
.plot-fit {
  stroke: var(--petrol);
  stroke-width: 1.5;
  stroke-dasharray: 5 4;
  opacity: 0.55;
}
.plot-points circle { fill: var(--verdigris); opacity: 0.85; }
.plot-points circle.is-outlier { fill: var(--amber); }
.plot-tick text { font-family: var(--font-sans); font-size: 9px; fill: var(--slate-light); text-anchor: middle; }
.plot-label { font-family: var(--font-sans); font-size: 10px; fill: var(--slate); text-anchor: middle; }

.plot-readout {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.5rem;
  margin-top: 0.9rem;
  padding-top: 0.9rem;
  border-top: 1px solid var(--line);
}
.plot-readout div { display: flex; flex-direction: column; }
.plot-stat { font-size: var(--step-2); font-weight: 600; letter-spacing: -0.02em; }
.plot-stat-name { font-family: var(--font-sans); font-size: 0.72rem; color: var(--slate); }

.hero-figure figcaption {
  margin-top: 0.9rem;
  font-size: var(--step--1);
  color: var(--slate);
  max-width: 46ch;
}

/* One deliberate page-load moment: the data points arrive on the plot */
.plot-points circle {
  opacity: 0;
  transform: translateY(6px);
  transform-box: fill-box;
  transform-origin: center;
  animation: point-in 0.5s var(--ease) forwards;
}
@keyframes point-in {
  to { opacity: 0.85; transform: translateY(0); }
}

/* ---------- 7. About ---------- */
.about-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: clamp(2rem, 5vw, 4rem);
  align-items: start;
}
.about-intro p { color: var(--slate); }
.about-intro p:first-of-type { color: var(--petrol); font-size: var(--step-1); }

.about-panel {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: clamp(1.5rem, 3vw, 2rem);
}
.panel-title { font-size: var(--step-1); margin-bottom: 1.4rem; }

.process { display: grid; gap: 1.35rem; }
.process li { display: grid; grid-template-columns: 34px 1fr; gap: 0.9rem; align-items: start; }
.process-step {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  background: var(--paper-warm);
  border: 1px solid var(--line);
  font-family: var(--font-sans);
  font-size: var(--step--1);
  font-weight: 600;
  color: var(--verdigris-dk);
}
.process h4 { font-size: var(--step-0); margin-bottom: 0.2em; }
.process p { font-size: var(--step--1); color: var(--slate); margin: 0; }

/* ---------- 8. Services ---------- */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.card {
  background: var(--white);
  padding: clamp(1.5rem, 3vw, 2rem);
  transition: background-color 0.2s var(--ease);
}
.card:hover { background: #fbfcfc; }
.card:hover .card-icon { border-color: var(--verdigris); color: var(--verdigris); }

.card-icon {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  margin-bottom: 1.1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  color: var(--petrol);
  transition: border-color 0.2s var(--ease), color 0.2s var(--ease);
}
.card-icon svg {
  width: 22px;
  height: 22px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.card h3 { font-size: var(--step-1); }
.card p { font-size: var(--step--1); color: var(--slate); margin: 0; }

/* ---------- 9. Benefits and stats ---------- */
.benefits-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: clamp(2rem, 5vw, 4rem);
  align-items: start;
}

.benefit-list { display: grid; gap: 1.6rem; margin: 0; }
.benefit { padding-left: 1.25rem; border-left: 2px solid var(--verdigris); }
.benefit dt { font-family: var(--font-sans); font-weight: 600; font-size: var(--step-1); margin-bottom: 0.25em; }
.benefit dd { margin: 0; color: var(--slate); }

.stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  overflow: hidden;
}
.stat { background: var(--white); padding: 1.5rem 1.25rem; }
.stat-value {
  display: block;
  font-size: var(--step-3);
  font-weight: 600;
  letter-spacing: -0.03em;
  color: var(--petrol);
}
.stat-label { display: block; margin-top: 0.3rem; font-size: 0.8rem; color: var(--slate); line-height: 1.45; }

/* ---------- 10. Contact ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(2rem, 5vw, 4rem);
  align-items: start;
}
.contact-intro p { color: rgba(255, 255, 255, 0.72); }

.contact-details {
  display: grid;
  gap: 1rem;
  margin-top: 2rem;
  padding-top: 1.75rem;
  border-top: 1px solid var(--line-dark);
}
.contact-details li { display: grid; grid-template-columns: 90px 1fr; gap: 1rem; align-items: start; }
.contact-key { font-size: 0.78rem; color: var(--slate-light); padding-top: 0.2em; }
.contact-value { color: rgba(255, 255, 255, 0.9); }

.contact-form {
  background: var(--white);
  border-radius: var(--radius-lg);
  padding: clamp(1.5rem, 3vw, 2.25rem);
  color: var(--petrol);
}

.form-row { margin-bottom: 1.1rem; }
.form-row label {
  display: block;
  margin-bottom: 0.4rem;
  font-size: var(--step--1);
  font-weight: 500;
}
.optional { color: var(--slate-light); font-weight: 400; }

.contact-form input[type="text"],
.contact-form input[type="email"],
.contact-form select,
.contact-form textarea {
  width: 100%;
  padding: 0.7rem 0.85rem;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-size: var(--step-0);
  color: var(--petrol);
  transition: border-color 0.18s var(--ease), box-shadow 0.18s var(--ease);
}
.contact-form textarea { resize: vertical; min-height: 120px; }

.contact-form input:focus,
.contact-form select:focus,
.contact-form textarea:focus {
  outline: none;
  border-color: var(--verdigris);
  box-shadow: 0 0 0 3px rgba(31, 122, 107, 0.14);
}

.contact-form .is-invalid { border-color: var(--danger); }

.field-error {
  margin: 0.35rem 0 0;
  min-height: 0;
  font-family: var(--font-sans);
  font-size: 0.8rem;
  color: var(--danger);
}

.form-check {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.6rem;
  align-items: start;
}
.form-check input { margin-top: 0.35rem; width: 16px; height: 16px; accent-color: var(--verdigris); }
.form-check label { margin: 0; font-weight: 400; color: var(--slate); }
.form-check .field-error { grid-column: 1 / -1; }

.form-status {
  margin: 0.9rem 0 0;
  font-family: var(--font-sans);
  font-size: var(--step--1);
  color: var(--verdigris-dk);
}
.form-status.is-error { color: var(--danger); }

/* ---------- 11. Footer ---------- */
.site-footer {
  background: var(--petrol-soft);
  color: rgba(255, 255, 255, 0.72);
  padding-top: clamp(2.5rem, 5vw, 4rem);
  font-size: var(--step--1);
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr;
  gap: 2.5rem;
  padding-bottom: 2.5rem;
}
.footer-name { font-family: var(--font-sans); font-weight: 600; font-size: var(--step-1); color: var(--white); margin-bottom: 0.6em; }
.footer-blurb { max-width: 40ch; }
.footer-address { margin-top: 1rem; line-height: 1.7; }

.footer-heading {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--white);
  margin-bottom: 1rem;
}
.footer-col ul { display: grid; gap: 0.55rem; }
.footer-col a,
.site-footer a { color: rgba(255, 255, 255, 0.72); }
.footer-col a:hover,
.site-footer a:hover { color: var(--white); }

.footer-bar {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.5rem;
  padding-top: 1.5rem;
  padding-bottom: 1.75rem;
  border-top: 1px solid var(--line-dark);
  font-size: 0.8rem;
}
.footer-bar p { margin: 0; }
.footer-legal { color: var(--slate-light); }

/* ---------- 12. Motion and responsive ---------- */
.reveal {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.5s var(--ease), transform 0.5s var(--ease);
}
.reveal.is-visible { opacity: 1; transform: none; }

@media (max-width: 960px) {
  .hero-grid,
  .about-grid,
  .benefits-grid,
  .contact-grid { grid-template-columns: 1fr; }

  .hero-title { max-width: 20ch; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 760px) {
  .nav-toggle { display: inline-flex; }

  .primary-nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 0 var(--gutter);
    background: var(--paper);
    border-bottom: 1px solid var(--line);
    max-height: 0;
    overflow: hidden;
    visibility: hidden;
    transition: max-height 0.28s var(--ease), padding 0.28s var(--ease), visibility 0.28s;
  }
  .primary-nav.is-open {
    visibility: visible;
    max-height: 420px;
    padding: 0.5rem var(--gutter) 1.25rem;
  }

  .nav-list { flex-direction: column; align-items: stretch; gap: 0; }
  .nav-list a { display: block; padding: 0.85rem 0; border-bottom: 1px solid var(--line); font-size: var(--step-0); }
  .nav-list a::after { display: none; }

  .nav-cta { margin-top: 1rem; justify-content: center; }
}

@media (max-width: 520px) {
  :root { --gutter: 1.15rem; }
  .brand-legal { display: none; }
  .stats { grid-template-columns: 1fr; }
  .contact-details li { grid-template-columns: 1fr; gap: 0.15rem; }
  .hero-actions .btn { flex: 1 1 100%; }
  .footer-grid { grid-template-columns: 1fr; gap: 2rem; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
  .plot-points circle { opacity: 0.85; transform: none; }
  .reveal { opacity: 1; transform: none; }
}

@media print {
  .site-header, .nav-toggle, .hero-actions, .contact-form { display: none; }
  body { background: #fff; }
}