:root {
  --bg: #f3f2ee;
  --paper: #ffffff;
  --text: #2b2b2b;
  --muted: #63625c;
  --accent: #2f5d8a;
  --accent-light: #4372a3;
  --accent-dark: #1f3f5c;
  --border: #dedad0;
  --steel: #b9c2c9;
  --steel-dark: #7c8790;
  --font-head: "Poppins", "Segoe UI", Verdana, Arial, sans-serif;
  --font-body: "Inter", "Segoe UI", Verdana, Arial, sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
}

/* --- Header --- */

.site-header {
  background: linear-gradient(155deg, var(--accent-dark) 0%, #294f74 60%, var(--accent) 100%);
  color: #fff;
  padding: 3rem 1rem 0 1rem;
  position: relative;
  overflow: hidden;
}

.header-inner {
  max-width: 900px;
  margin: 0 auto;
  padding-bottom: 2.4rem;
  position: relative;
  z-index: 1;
}

.eyebrow {
  margin: 0 0 0.6rem 0;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 0.78rem;
  color: #b9d0e4;
  font-weight: 600;
}

.site-header h1 {
  margin: 0 0 0.7rem 0;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 2.1rem;
  max-width: 22ch;
}

.subtitle {
  margin: 0;
  color: #d7e2ec;
  font-size: 1.02rem;
  max-width: 52ch;
}

.road {
  position: relative;
  z-index: 1;
  line-height: 0;
}

.road svg {
  width: 100%;
  height: 26px;
  display: block;
}

.road rect {
  fill: #1a2f43;
}

.road line {
  stroke: #e8b93c;
  stroke-width: 3;
  stroke-dasharray: 14 12;
}

/* --- Nav --- */

.site-nav {
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(6px);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
}

.site-nav ul {
  max-width: 900px;
  margin: 0 auto;
  padding: 0.5rem 1rem;
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.2rem 0.3rem;
}

.site-nav a {
  color: var(--accent-dark);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  padding: 0.4rem 0.7rem;
  border-radius: 999px;
  display: inline-block;
  transition: background 0.15s ease, color 0.15s ease;
}

.site-nav a:hover {
  background: #eaf0f6;
}

.site-nav a.active {
  background: var(--accent);
  color: #fff;
}

/* --- Layout --- */

main {
  max-width: 900px;
  margin: 0 auto;
  padding: 2rem 1rem 3rem 1rem;
}

.section {
  background: var(--paper);
  border: 1px solid var(--border);
  border-left: 4px solid var(--accent);
  border-radius: 10px;
  padding: 1.75rem 2rem;
  margin-bottom: 1.75rem;
  box-shadow: 0 1px 3px rgba(31, 63, 92, 0.06);
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.section.reveal {
  opacity: 1;
  transform: translateY(0);
}

#intro.section {
  border-left-color: var(--steel-dark);
  background: #fafaf7;
}

.section-head {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  border-bottom: 2px solid var(--border);
  padding-bottom: 0.7rem;
  margin-bottom: 0.3rem;
}

.section-head .icon {
  flex: none;
  width: 40px;
  height: 40px;
  border-radius: 10px;
  background: #eaf0f6;
  color: var(--accent);
  display: flex;
  align-items: center;
  justify-content: center;
}

.section-head .icon svg {
  width: 22px;
  height: 22px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.7;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.section h2 {
  margin: 0;
  color: var(--accent-dark);
  font-family: var(--font-head);
  font-size: 1.25rem;
  font-weight: 600;
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
}

.step {
  font-family: var(--font-head);
  font-size: 0.85rem;
  font-weight: 700;
  color: #fff;
  background: var(--accent);
  border-radius: 999px;
  width: 1.6em;
  height: 1.6em;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: none;
}

.section p {
  margin: 0.95rem 0 0 0;
}

.section a {
  color: var(--accent);
  font-weight: 500;
}

.conclusie-section {
  background: #f4f8fb;
  border-left-color: #2f8a5d;
}

.conclusie-section .icon {
  background: #e1f0e7;
  color: #2f8a5d;
}

/* --- Animation section --- */

.animation-section {
  text-align: center;
}

.animation-section p {
  text-align: left;
}

.car-stage {
  max-width: 480px;
  margin: 1.2rem auto 0.5rem auto;
  background: linear-gradient(180deg, #eef2f5 0%, #e4e9ed 100%);
  border-radius: 10px;
  padding: 0.75rem;
  border: 1px solid var(--border);
}

#carSvg {
  width: 100%;
  height: auto;
  display: block;
}

#carSvg .lane {
  stroke: #c7cdd2;
  stroke-width: 2;
  stroke-dasharray: 10 8;
}

#carSvg .shadow {
  fill: #000;
  opacity: 0.1;
}

#part-chassis rect {
  fill: var(--steel-dark);
}

#part-engine rect {
  fill: #3a3a3a;
}
#part-engine line {
  stroke: #6b6b6b;
  stroke-width: 2;
}

#part-wheel-left circle,
#part-wheel-right circle {
  fill: #262626;
}
#part-wheel-left .hub,
#part-wheel-right .hub {
  fill: var(--steel);
}
.wheel .spokes line {
  stroke: #4a4a4a;
  stroke-width: 1.4;
}

#part-windows path {
  fill: #dbe7f0;
}

/* start state: pieces hidden / offset, JS adds .in class to animate in */
#part-chassis,
#part-engine,
#part-wheel-left,
#part-wheel-right,
#part-body,
#part-windows {
  opacity: 0;
  transition: opacity 0.6s cubic-bezier(.2, .7, .3, 1), transform 0.6s cubic-bezier(.2, .7, .3, 1);
}

#part-chassis {
  transform: translateY(20px);
}
#part-engine {
  transform: translateY(-16px);
}
#part-wheel-left {
  transform: translate(-40px, -10px) rotate(-90deg);
  transform-origin: 115px 140px;
}
#part-wheel-right {
  transform: translate(40px, -10px) rotate(90deg);
  transform-origin: 285px 140px;
}
#part-body {
  transform: translateY(-24px);
}
#part-windows {
  transform: translateY(-8px);
}

#carSvg.play #part-chassis.in,
#carSvg.play #part-engine.in,
#carSvg.play #part-body.in,
#carSvg.play #part-windows.in {
  opacity: 1;
  transform: translate(0, 0);
}

#carSvg.play #part-wheel-left.in,
#carSvg.play #part-wheel-right.in {
  opacity: 1;
  transform: translate(0, 0) rotate(0deg);
}

#carSvg.done .wheel {
  animation: roll 2.6s linear infinite;
  transform-box: fill-box;
  transform-origin: center;
}

@keyframes roll {
  0%, 70% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

.replay-btn {
  margin-top: 0.7rem;
  padding: 0.6rem 1.3rem;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 999px;
  font-size: 0.95rem;
  font-weight: 500;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  transition: background 0.15s ease, transform 0.1s ease;
}

.replay-btn svg {
  width: 16px;
  height: 16px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.replay-btn:hover {
  background: var(--accent-dark);
}

.replay-btn:active {
  transform: scale(0.97);
}

/* --- Bronnenlijst --- */

.bronlijst {
  padding-left: 1.2rem;
  margin-top: 0.9rem;
}

.bronlijst li {
  margin-bottom: 0.65rem;
  font-size: 0.93rem;
  color: var(--muted);
}

.bronlijst em {
  color: var(--text);
  font-style: normal;
  font-weight: 600;
}

/* --- Footer --- */

.site-footer {
  text-align: center;
  padding: 1.4rem 1rem 2.4rem 1rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.to-top {
  position: fixed;
  right: 1.1rem;
  bottom: 1.1rem;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  border: none;
  background: var(--accent);
  color: #fff;
  font-size: 1.1rem;
  cursor: pointer;
  box-shadow: 0 2px 8px rgba(31, 63, 92, 0.25);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease, background 0.15s ease;
}

.to-top.visible {
  opacity: 1;
  pointer-events: auto;
}

.to-top:hover {
  background: var(--accent-dark);
}

@media (max-width: 600px) {
  .site-header h1 {
    font-size: 1.5rem;
  }
  .section {
    padding: 1.25rem 1.25rem;
  }
  .section-head .icon {
    width: 34px;
    height: 34px;
  }
}