@import url('https://fonts.googleapis.com/css2?family=Vazirmatn:wght@300;400;500;600;700;800;900&display=swap');

:root {
  --bg: #070914;
  --panel: rgba(17, 22, 43, .76);
  --line: rgba(157, 148, 255, .17);
  --purple: #aa94ff;
  --cyan: #65efff;
  --text: #f3f2ff;
  --muted: #969bb8;
  --pink: #ff78b2;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--text);
  background:
    radial-gradient(ellipse at 15% 15%, rgba(92,62,185,.17), transparent 38%),
    radial-gradient(ellipse at 85% 75%, rgba(18,143,166,.10), transparent 35%),
    var(--bg);
  font-family: 'Vazirmatn', Tahoma, sans-serif;
  direction: rtl;
}

button {
  font: inherit;
  cursor: pointer;
}

.app-shell {
  position: relative;
  overflow: hidden;
  min-height: 100vh;
}

.ambient {
  position: fixed;
  width: 320px;
  height: 320px;
  border-radius: 50%;
  filter: blur(100px);
  opacity: .12;
  pointer-events: none;
  z-index: 0;
}

.ambient-one {
  background: #7d5cff;
  top: 15%;
  right: -180px;
}

.ambient-two {
  background: #16d9e8;
  bottom: 0;
  left: -190px;
}

.topbar, main {
  position: relative;
  z-index: 1;
}

.topbar {
  max-width: 1240px;
  margin: auto;
  padding: 24px 28px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid rgba(255,255,255,.06);
}

.brand {
  display: flex;
  align-items: center;
  gap: 11px;
  color: var(--text);
  text-decoration: none;
  font-size: 13px;
  font-weight: 700;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border-radius: 11px;
  color: white;
  font-size: 17px;
  background: linear-gradient(135deg,#8d74ff,#38d8e9);
  box-shadow: 0 0 24px #816bff55;
}

.top-status {
  color: var(--muted);
  font-size: 11px;
}

.top-status i,
.live-dot {
  display: inline-block;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: #50edb0;
  box-shadow: 0 0 12px #50edb0;
  margin-left: 7px;
}

main {
  max-width: 1240px;
  margin: auto;
  padding: 35px 28px 60px;
}

.screen {
  display: none;
  animation: appear .55s ease both;
}

.screen.active {
  display: block;
}

@keyframes appear {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: none; }
}

/* HERO */

.hero-grid {
  display: grid;
  grid-template-columns: 1.05fr .95fr;
  gap: 35px;
  align-items: center;
  min-height: 475px;
}

.hero-copy {
  padding: 35px 0;
}

.eyebrow {
  color: var(--cyan);
  font-size: 11px;
  letter-spacing: .5px;
  margin-bottom: 19px;
}

.eyebrow span {
  display: inline-block;
  width: 22px;
  height: 1px;
  background: var(--cyan);
  vertical-align: middle;
  margin-left: 8px;
}

h1 {
  direction: ltr;
  text-align: right;
  font-family: Arial, sans-serif;
  font-size: clamp(46px, 7vw, 86px);
  line-height: .91;
  letter-spacing: -4px;
  margin: 0 0 22px;
  font-weight: 900;
  text-shadow: 0 0 35px #9b8cff26;
}

h1 em {
  font-style: normal;
  color: transparent;
  -webkit-text-stroke: 1.4px #9e91ff;
  text-shadow: 0 0 35px #9b8cff44;
}

.hero-subtitle {
  font-size: 17px;
  font-weight: 700;
  margin: 0 0 12px;
}

.hero-description {
  color: var(--muted);
  font-size: 13px;
  line-height: 2.2;
  max-width: 500px;
}

.hero-actions {
  display: flex;
  align-items: center;
  gap: 22px;
  margin-top: 28px;
}

.primary-btn,
.secondary-btn {
  border: 0;
  border-radius: 12px;
  padding: 14px 22px;
  font-weight: 700;
  color: white;
  background: linear-gradient(105deg,#7864ec,#5c9bf6);
  box-shadow: 0 9px 28px #735eff35;
  transition: .25s;
}

.primary-btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 12px 34px #735eff65;
}

.primary-btn span {
  margin-right: 13px;
  font-size: 18px;
}

.text-btn,
.back-link {
  background: none;
  border: 0;
  color: var(--muted);
  font-size: 12px;
}

.text-btn:hover,
.back-link:hover {
  color: var(--cyan);
}

.hero-stats {
  display: flex;
  gap: 32px;
  margin-top: 45px;
}

.hero-stats div {
  display: flex;
  flex-direction: column;
  gap: 5px;
}

.hero-stats strong {
  color: var(--cyan);
  font-size: 18px;
  font-family: Arial;
}

.hero-stats span {
  color: var(--muted);
  font-size: 10px;
}

/* BRAIN VISUAL */

.visual-stage {
  height: 410px;
  position: relative;
  display: grid;
  place-items: center;
  isolation: isolate;
}

.brain-core {
  width: 280px;
  height: 260px;
  position: relative;
  z-index: 2;
  display: grid;
  place-items: center;
  transform-style: preserve-3d;
  filter:
    drop-shadow(0 0 15px #a18aff88)
    drop-shadow(0 0 35px #55e7f244);
  animation: brainFloat 5s ease-in-out infinite;
}

.brain-core svg {
  width: 100%;
  height: 100%;
  overflow: visible;
}

.brain-core canvas {
  display: block;
  width: 100% !important;
  height: 100% !important;
  outline: none;
  border: 0;
  touch-action: none;
}

@keyframes brainFloat {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-12px); }
}

.orbit {
  position: absolute;
  border-radius: 50%;
  box-shadow: 0 0 15px #8b7bff22;
}

.orbit-a {
  width: 300px;
  height: 160px;
  border: 2px solid transparent;
  border-top-color: #55e7f2;
  border-right-color: #9b8cff;
  animation: orbitSpin 12s linear infinite;
}

.orbit-b {
  width: 365px;
  height: 225px;
  border: 1px solid #55e7f277;
  animation: orbitReverse 18s linear infinite;
}

.orbit-c {
  width: 405px;
  height: 290px;
  border: 1px dashed #9b8cff88;
  opacity: .6;
  animation: orbitSpin 28s linear infinite;
}

@keyframes orbitSpin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

@keyframes orbitReverse {
  from { transform: rotate(0deg); }
  to { transform: rotate(-360deg); }
}

.floating-chip {
  position: absolute;
  z-index: 3;
  border: 1px solid rgba(170,148,255,.3);
  background: rgba(19,23,48,.94);
  backdrop-filter: blur(12px);
  padding: 10px 14px;
  border-radius: 10px;
  font-size: 10px;
  color: #d9d7ff;
  box-shadow: 0 8px 30px #0005;
}

.chip-top {
  top: 65px;
  right: 2px;
}

.chip-bottom {
  bottom: 62px;
  left: 0;
}

.chip-bottom b {
  color: #52edb0;
  margin-right: 8px;
}

.chip-dot {
  display: inline-block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--cyan);
  margin-left: 7px;
  box-shadow: 0 0 9px var(--cyan);
}

.visual-caption {
  position: absolute;
  bottom: 12px;
  direction: ltr;
  font: 9px Arial;
  letter-spacing: 4px;
  color: #77739e;
}

/* CARDS */

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3,1fr);
  gap: 14px;
  margin-top: 15px;
}

.feature-card,
.glass-card,
.result-card {
  background: linear-gradient(145deg,rgba(25,30,57,.84),rgba(11,15,31,.82));
  border: 1px solid var(--line);
  border-radius: 17px;
  box-shadow: inset 0 1px rgba(255,255,255,.035), 0 15px 40px #0002;
  transition: border-color .25s ease, box-shadow .25s ease;
}

.feature-card:hover,
.glass-card:hover,
.result-card:hover {
  border-color: rgba(170,148,255,.4);
  box-shadow: 0 15px 40px rgba(0,0,0,.25), 0 0 20px rgba(155,140,255,.08);
}

.feature-card {
  padding: 20px;
  display: flex;
  align-items: center;
  gap: 13px;
  position: relative;
  overflow: hidden;
}

.feature-icon {
  color: var(--cyan);
  font-size: 26px;
}

.feature-card h3 {
  font-size: 12px;
  margin: 0 0 5px;
}

.feature-card p {
  color: var(--muted);
  font-size: 10px;
  margin: 0;
}

.feature-card > b {
  position: absolute;
  left: 16px;
  top: 14px;
  color: #6d6993;
  font: 11px Arial;
}

.site-footer {
  display: flex;
  justify-content: space-between;
  color: #686d8b;
  font-size: 10px;
  padding-top: 30px;
}

/* SECTION HEADINGS */

.section-heading {
  text-align: center;
  margin: 35px 0 30px;
}

.section-heading h2 {
  font-size: clamp(26px,4vw,38px);
  margin: 0 0 8px;
}

.section-heading h2 em {
  font-style: normal;
  color: var(--purple);
}

.section-heading p {
  color: var(--muted);
  font-size: 12px;
}

/* GUIDE */

.guide-layout {
  display: grid;
  grid-template-columns: 1.5fr .8fr;
  gap: 18px;
}

.glass-card {
  padding: 27px;
}

.guide-number {
  color: var(--cyan);
  font: 12px Arial;
  margin-bottom: 8px;
}

.guide-main h3,
.guide-side h3,
.chart-card h3 {
  font-size: 15px;
  margin: 0 0 9px;
}

.guide-main p {
  color: var(--muted);
  font-size: 12px;
  line-height: 2.1;
  margin: 0 0 24px;
}

.arrow-demo {
  display: flex;
  gap: 18px;
  margin: 15px 0 28px;
}

.arrow-demo span {
  display: grid;
  place-items: center;
  width: 72px;
  height: 65px;
  border-radius: 10px;
  color: #bcaaff;
  border: 1px solid rgba(170,148,255,.35);
  background: linear-gradient(145deg,rgba(155,140,255,.2),rgba(85,231,242,.08));
  font-size: 42px;
  font-weight: 900;
  box-shadow: 0 0 18px rgba(155,140,255,.12);
}

.stop-demo {
  display: inline-block;
  border: 1px solid #ff5c9a;
  color: #ff8db8;
  padding: 8px 20px;
  border-radius: 8px;
  font-size: 12px;
  box-shadow: 0 0 18px #ff5c9a22;
}

.guide-side ul {
  padding-right: 18px;
  color: var(--muted);
  font-size: 11px;
  line-height: 2.8;
  margin: 18px 0 28px;
}

.full-btn {
  width: 100%;
}

.back-link {
  display: block;
  margin: 22px auto 0;
}

/* SETUP */

.setup-card {
  max-width: 650px;
  margin: auto;
}

.setup-card label {
  display: block;
  font-size: 13px;
  margin-bottom: 16px;
}

.trial-options {
  display: grid;
  grid-template-columns: repeat(3,1fr);
  gap: 12px;
}

.trial-option {
  padding: 17px;
  border: 1px solid var(--line);
  border-radius: 13px;
  color: var(--muted);
  background: #0b1021;
  display: flex;
  flex-direction: column;
  gap: 5px;
}

.trial-option strong {
  font: 26px Arial;
  color: white;
}

.trial-option span {
  font-size: 10px;
}

.trial-option.selected {
  border-color: var(--purple);
  background: #8b79ff19;
  box-shadow: 0 0 20px #8b79ff19;
}

.setup-info {
  margin: 25px 0;
  border-top: 1px solid var(--line);
}

.setup-info div {
  display: flex;
  justify-content: space-between;
  padding: 13px 0;
  border-bottom: 1px solid #ffffff0a;
  font-size: 11px;
}

.setup-info span {
  color: var(--muted);
}

.setup-info strong {
  font-weight: 600;
}

/* EXPERIMENT */

.experiment-top {
  display: flex;
  justify-content: space-between;
  color: var(--muted);
  font-size: 11px;
  margin: 18px 0 12px;
}

.progress-track {
  height: 5px;
  background: #252943;
  border-radius: 10px;
  overflow: hidden;
}

.progress-track div {
  height: 100%;
  width: 0;
  border-radius: inherit;
  background: linear-gradient(90deg,var(--purple),var(--cyan));
  transition: width .2s;
  box-shadow: 0 0 12px #65dff0;
}

.live-metrics {
  display: grid;
  grid-template-columns: repeat(3,1fr);
  gap: 10px;
  margin: 18px 0;
}

.live-metrics div {
  background: #11162b;
  border: 1px solid var(--line);
  padding: 12px;
  border-radius: 11px;
  display: flex;
  flex-direction: column;
  gap: 5px;
}

.live-metrics span {
  color: var(--muted);
  font-size: 9px;
}

.live-metrics strong {
  font: 18px Arial;
  color: var(--cyan);
}

.experiment-card {
  max-width: 800px;
  margin: 18px auto;
  min-height: 365px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.stimulus-label {
  color: var(--muted);
  font-size: 12px;
}

.stimulus-zone {
  width: 220px;
  height: 175px;
  display: grid;
  place-items: center;
  font: 900 clamp(105px,20vw,155px) Arial;
  color: #c6b8ff;
  text-shadow: 0 0 12px rgba(170,148,255,.9), 0 0 30px rgba(155,140,255,.55), 0 0 55px rgba(85,231,242,.2);
  transition: .15s;
}

.stimulus-zone.stop {
  color: var(--pink);
  text-shadow: 0 0 15px rgba(255,92,154,.9), 0 0 40px rgba(255,92,154,.5);
}

.response-buttons {
  display: flex;
  gap: 16px;
  direction: ltr;
}

.response-btn {
  width: 112px;
  height: 82px;
  border-radius: 16px;
  border: 1px solid rgba(170,148,255,.55);
  background: linear-gradient(145deg,rgba(126,108,255,.2),rgba(85,231,242,.09));
  color: white;
  font: 43px Arial;
  box-shadow: 0 8px 25px rgba(0,0,0,.2), 0 0 18px rgba(155,140,255,.1);
  transition: .15s;
}

.response-btn:active {
  transform: scale(.93);
  background: rgba(85,231,242,.2);
  box-shadow: 0 0 25px rgba(85,231,242,.3);
}

.response-btn small {
  display: block;
  font: 10px 'Vazirmatn';
  color: var(--muted);
  margin-top: 3px;
}

.experiment-hint {
  color: var(--muted);
  font-size: 10px;
  margin-top: 20px;
  min-height: 17px;
}

.test-bottom {
  display: flex;
  justify-content: space-between;
  color: #777c9a;
  font-size: 10px;
}

/* RESULTS */

.result-highlight {
  display: flex;
  justify-content: space-around;
  align-items: center;
  max-width: 800px;
  margin: auto;
}

.result-highlight > div:first-child {
  display: flex;
  flex-direction: column;
  gap: 5px;
}

.result-highlight span {
  color: var(--muted);
  font-size: 11px;
}

.result-highlight strong {
  font: 42px Arial;
  color: var(--cyan);
}

.result-highlight small {
  color: var(--muted);
  font-size: 10px;
}

.result-ring {
  width: 125px;
  height: 125px;
  border-radius: 50%;
  border: 7px solid #7565dc;
  box-shadow: 0 0 28px #8d7cff35, inset 0 0 22px #8d7cff18;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.result-ring span {
  color: white;
  font: 26px Arial;
}

.result-grid {
  display: grid;
  grid-template-columns: repeat(4,1fr);
  gap: 12px;
  margin: 17px 0;
}

.result-card {
  padding: 17px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.result-card span {
  color: var(--muted);
  font-size: 10px;
}

.result-card strong {
  font: 23px Arial;
  color: var(--purple);
}

.chart-card {
  max-width: 800px;
  margin: auto;
}

.chart-row {
  display: grid;
  grid-template-columns: 100px 1fr 40px;
  gap: 12px;
  align-items: center;
  margin-top: 19px;
  font-size: 10px;
}

.chart-row span {
  color: var(--muted);
}

.chart-row b {
  font: 11px Arial;
}

.chart-track {
  height: 8px;
  background: #292d49;
  border-radius: 8px;
  overflow: hidden;
}

.chart-track i {
  display: block;
  height: 100%;
  width: 0;
  border-radius: 8px;
  background: linear-gradient(90deg,var(--purple),var(--cyan));
}

.chart-note,
.disclaimer {
  color: #777c98;
  font-size: 9px;
  line-height: 2;
}

.result-actions {
  display: flex;
  justify-content: center;
  gap: 12px;
  margin-top: 22px;
}

.secondary-btn {
  background: #1a203a;
  border: 1px solid var(--line);
  box-shadow: none;
}

.disclaimer {
  text-align: center;
  max-width: 650px;
  margin: 18px auto;
}

/* MOBILE */

@media (max-width: 760px) {
  .topbar {
    padding: 17px 18px;
  }

  main {
    padding: 20px 17px 40px;
  }

  .hero-grid {
    grid-template-columns: 1fr;
    gap: 0;
  }

  .hero-copy {
    padding: 38px 0 5px;
  }

  h1 {
    font-size: clamp(48px,13vw,72px);
    letter-spacing: -3px;
  }

  .visual-stage {
    height: 310px;
    margin-top: -5px;
    overflow: hidden;
  }

  .brain-core {
    width: 220px;
    height: 215px;
  }

  .orbit-a {
    width: 245px;
    height: 130px;
  }

  .orbit-b {
    width: 300px;
    height: 180px;
  }

  .orbit-c {
    width: 330px;
    height: 230px;
  }

  .chip-top {
    right: 0;
    top: 35px;
  }

  .chip-bottom {
    bottom: 30px;
    left: 0;
  }

  .feature-grid,
  .guide-layout {
    grid-template-columns: 1fr;
  }

  .feature-card {
    padding: 16px;
  }

  .result-grid {
    grid-template-columns: repeat(2,1fr);
  }

  .live-metrics {
    gap: 6px;
  }

  .live-metrics div {
    padding: 9px;
  }

  .live-metrics strong {
    font-size: 15px;
  }

  .experiment-card {
    min-height: 340px;
    padding: 20px 12px;
  }

  .stimulus-zone {
    width: 200px;
    height: 165px;
    font-size: 115px;
  }

  .response-btn {
    width: 105px;
    height: 78px;
    font-size: 40px;
  }

  .arrow-demo span {
    width: 65px;
    height: 60px;
    font-size: 38px;
  }

  .result-highlight {
    padding: 20px;
  }

  .result-ring {
    width: 105px;
    height: 105px;
  }

  .site-footer {
    gap: 12px;
  }
}

@media (max-width: 390px) {
  .hero-actions {
    gap: 12px;
  }

  .primary-btn {
    padding: 13px 16px;
    font-size: 11px;
  }

  .text-btn {
    font-size: 10px;
  }

  .hero-stats {
    gap: 20px;
  }

  .result-highlight strong {
    font-size: 32px;
  }

  .chart-row {
    grid-template-columns: 82px 1fr 34px;
    gap: 7px;
  }
}

/* =====================================
   PREMIUM NEON STOP SIGNAL ARROWS
===================================== */

#testStimulus,
#practiceStimulus {
  width: 150px;
  height: 150px;
  margin: 24px auto;

  display: flex;
  align-items: center;
  justify-content: center;

  font-family: Arial, sans-serif;
  font-size: 86px;
  font-weight: 900;
  line-height: 1;

  color: #65efff;

  background:
    radial-gradient(
      circle at 50% 45%,
      rgba(68, 220, 255, 0.20),
      rgba(24, 35, 67, 0.96) 70%
    );

  border: 2px solid rgba(91, 226, 255, 0.8);

  clip-path: polygon(
    25% 4%,
    75% 4%,
    100% 50%,
    75% 96%,
    25% 96%,
    0% 50%
  );

  filter:
    drop-shadow(0 0 8px rgba(60, 225, 255, 0.65))
    drop-shadow(0 0 22px rgba(60, 225, 255, 0.3));

  text-shadow:
    0 0 8px #55eaff,
    0 0 20px rgba(65, 220, 255, 0.8);

  animation: neonArrowIn 0.3s ease-out;
}

/* فلش چپ و راست */

#testStimulus:not(.stop),
#practiceStimulus:not(.stop) {
  color: #65efff;
}

/* حالت توقف */

#testStimulus.stop,
#practiceStimulus.stop {
  color: #ff80b5;

  background:
    radial-gradient(
      circle,
      rgba(255, 75, 145, 0.24),
      rgba(37, 23, 53, 0.98) 72%
    );

  border-color: #ff75ad;

  filter:
    drop-shadow(0 0 10px rgba(255, 85, 155, 0.8))
    drop-shadow(0 0 24px rgba(255, 85, 155, 0.35));

  text-shadow:
    0 0 10px #ff70b0,
    0 0 24px rgba(255, 85, 155, 0.8);
}

/* انیمیشن ورود */

@keyframes neonArrowIn {
  0% {
    opacity: 0.3;
    transform: scale(0.78);
  }

  70% {
    transform: scale(1.07);
  }

  100% {
    opacity: 1;
    transform: scale(1);
  }
}

/* نمایش در گوشی */

@media (max-width: 600px) {
  #testStimulus,
  #practiceStimulus {
    width: 132px;
    height: 132px;
    font-size: 76px;
  }
}

/* =====================================
   PREMIUM NEON STOP SIGNAL ARROWS
===================================== */

#testStimulus,
#practiceStimulus {
  width: 150px;
  height: 150px;
  margin: 24px auto;

  display: flex;
  align-items: center;
  justify-content: center;

  font-family: Arial, sans-serif;
  font-size: 86px;
  font-weight: 900;
  line-height: 1;

  color: #65efff;

  background:
    radial-gradient(
      circle at 50% 45%,
      rgba(68, 220, 255, 0.20),
      rgba(24, 35, 67, 0.96) 70%
    );

  border: 2px solid rgba(91, 226, 255, 0.8);

  clip-path: polygon(
    25% 4%,
    75% 4%,
    100% 50%,
    75% 96%,
    25% 96%,
    0% 50%
  );

  filter:
    drop-shadow(0 0 8px rgba(60, 225, 255, 0.65))
    drop-shadow(0 0 22px rgba(60, 225, 255, 0.3));

  text-shadow:
    0 0 8px #55eaff,
    0 0 20px rgba(65, 220, 255, 0.8);

  animation: neonArrowIn 0.3s ease-out;
}

/* فلش چپ و راست */

#testStimulus:not(.stop),
#practiceStimulus:not(.stop) {
  color: #65efff;
}

/* حالت توقف */

#testStimulus.stop,
#practiceStimulus.stop {
  color: #ff80b5;

  background:
    radial-gradient(
      circle,
      rgba(255, 75, 145, 0.24),
      rgba(37, 23, 53, 0.98) 72%
    );

  border-color: #ff75ad;

  filter:
    drop-shadow(0 0 10px rgba(255, 85, 155, 0.8))
    drop-shadow(0 0 24px rgba(255, 85, 155, 0.35));

  text-shadow:
    0 0 10px #ff70b0,
    0 0 24px rgba(255, 85, 155, 0.8);
}

/* انیمیشن ورود */

@keyframes neonArrowIn {
  0% {
    opacity: 0.3;
    transform: scale(0.78);
  }

  70% {
    transform: scale(1.07);
  }

  100% {
    opacity: 1;
    transform: scale(1);
  }
}

/* نمایش در گوشی */

@media (max-width: 600px) {
  #testStimulus,
  #practiceStimulus {
    width: 132px;
    height: 132px;
    font-size: 76px;
  }
}

/* =====================================
   ABOUT SCREEN — NEURAL GLASS DESIGN
===================================== */

#aboutScreen {
  position: relative;
  overflow: hidden;
  isolation: isolate;
}

#aboutScreen::before,
#aboutScreen::after {
  content: "";
  position: absolute;
  width: 280px;
  height: 280px;
  border-radius: 50%;
  filter: blur(90px);
  opacity: .16;
  pointer-events: none;
  z-index: -1;
}

#aboutScreen::before {
  background: #8465ff;
  top: 100px;
  right: -140px;
}

#aboutScreen::after {
  background: #35dce9;
  bottom: 100px;
  left: -150px;
}

#aboutScreen .section-heading {
  text-align: center;
  margin-bottom: 32px;
}

#aboutScreen .section-heading h2 {
  letter-spacing: -1px;
  text-shadow: 0 0 24px rgba(151, 119, 255, .3);
}

#aboutScreen .section-heading h2 em {
  color: #8c80ff;
  font-style: normal;
}

#aboutScreen .section-heading p {
  color: rgba(220, 226, 255, .7);
  line-height: 2;
}

#aboutScreen .glass-card {
  position: relative;
  background:
    linear-gradient(145deg,
      rgba(35, 39, 76, .88),
      rgba(13, 20, 43, .94));
  border: 1px solid rgba(148, 139, 255, .22);
  border-radius: 22px;
  box-shadow:
    0 15px 45px rgba(0, 0, 0, .22),
    inset 0 1px 0 rgba(255, 255, 255, .06);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
}

#aboutScreen .guide-main {
  padding: 28px;
  margin-bottom: 20px;
}

#aboutScreen .guide-number {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  margin: 28px 0 14px;
  border-radius: 12px;
  color: #b8b0ff;
  font-size: 14px;
  font-weight: 800;
  background: linear-gradient(
    135deg,
    rgba(137, 112, 255, .22),
    rgba(49, 216, 232, .12)
  );
  border: 1px solid rgba(151, 137, 255, .4);
  box-shadow: 0 0 18px rgba(133, 111, 255, .12);
}

#aboutScreen .guide-main h3 {
  color: #f0edff;
  font-size: 18px;
  margin: 0 0 12px;
}

#aboutScreen .guide-main h4 {
  color: #7feaf0;
  font-size: 14px;
  margin: 24px 0 8px;
  letter-spacing: .3px;
}

#aboutScreen .guide-main p {
  color: rgba(224, 229, 255, .76);
  font-size: 14px;
  line-height: 2.2;
  text-align: justify;
  margin: 0 0 14px;
}

#aboutScreen .arrow-demo {
  display: flex;
  justify-content: center;
  gap: 24px;
  margin: 20px 0;
}

#aboutScreen .arrow-demo span {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 64px;
  height: 64px;
  border-radius: 18px;
  color: #71efff;
  font-size: 38px;
  background: rgba(56, 205, 238, .09);
  border: 1px solid rgba(88, 225, 255, .45);
  box-shadow: 0 0 22px rgba(57, 215, 255, .12);
}

#aboutScreen .stop-demo {
  width: fit-content;
  margin: 18px auto 24px;
  padding: 13px 30px;
  border-radius: 14px;
  color: #ff9ac4;
  font-weight: 900;
  letter-spacing: 3px;
  background: rgba(255, 76, 145, .1);
  border: 1px solid rgba(255, 100, 165, .5);
  box-shadow: 0 0 24px rgba(255, 76, 145, .14);
}

#aboutScreen .guide-side {
  padding: 24px;
}

#aboutScreen .guide-side h3 {
  color: #a99bff;
  margin-bottom: 18px;
}

#aboutScreen .guide-side ul {
  padding-right: 20px;
  color: rgba(224, 229, 255, .78);
  line-height: 2.5;
  font-size: 14px;
}

#aboutScreen .back-link {
  display: block;
  margin: 24px auto;
  padding: 12px 22px;
  color: #8deaf4;
  border: 1px solid rgba(89, 218, 239, .3);
  border-radius: 12px;
  background: rgba(54, 198, 224, .07);
  transition: .25s ease;
}

#aboutScreen .back-link:active {
  transform: scale(.97);
  box-shadow: 0 0 20px rgba(70, 220, 240, .18);
}

@media(max-width:600px) {
  #aboutScreen .guide-main {
    padding: 20px;
  }

  #aboutScreen .guide-main h3 {
    font-size: 16px;
  }

  #aboutScreen .guide-main p {
    font-size: 13px;
    line-height: 2.1;
  }

  #aboutScreen .section-heading {
    margin-bottom: 22px;
  }
}

/* ==================================
   INTERACTIVE TIMELINE
================================== */

.timing-visual {
  margin-top: 24px;
  padding: 26px 20px;
  overflow: hidden;
  direction: rtl;
}

.timing-heading {
  text-align: center;
  margin-bottom: 24px;
}

.timing-heading .eyebrow {
  color: #a99aff;
  font-size: 11px;
  letter-spacing: 2px;
}

.timing-heading h3 {
  margin: 10px 0;
  color: #f4f0ff;
}

.timing-heading p {
  color: #a8abc4;
  font-size: 13px;
}

.timing-tabs {
  display: flex;
  justify-content: center;
  gap: 12px;
  margin-bottom: 32px;
}

.timing-tab {
  min-width: 82px;
  padding: 12px 18px;
  border: 1px solid rgba(169,154,255,.25);
  border-radius: 12px;
  background: rgba(255,255,255,.035);
  color: #c7c2e8;
  font-weight: 800;
  cursor: pointer;
  transition: .25s ease;
}

.timing-tab.active {
  color: #fff;
  background: linear-gradient(135deg,#8269e8,#5545a9);
  border-color: #b4a5ff;
  box-shadow: 0 0 22px rgba(143,116,255,.3);
  transform: translateY(-2px);
}

.timing-display {
  padding: 20px 12px;
  border-radius: 18px;
  background: rgba(7,10,28,.55);
  border: 1px solid rgba(169,154,255,.12);
  text-align: center;
}

.timing-track {
  position: relative;
  height: 70px;
  margin: 12px 8px 5px;
  direction: ltr;
}

.timing-line {
  position: absolute;
  top: 34px;
  left: 4%;
  right: 4%;
  height: 3px;
  border-radius: 10px;
  background: linear-gradient(
    90deg,
    #9b8cff,
    #55e7f2,
    #ff5c9a
  );
  opacity: .65;
}

.timing-point {
  position: absolute;
  top: 26px;
  width: 17px;
  height: 17px;
  border-radius: 50%;
  border: 3px solid #fff;
  z-index: 2;
}

.point-go {
  left: 4%;
  background: #9b8cff;
}

.point-stop {
  left: 42%;
  background: #ff5c9a;
}

.point-response {
  left: 88%;
  background: #55e7f2;
}

.timing-marker {
  position: absolute;
  top: 12px;
  left: 4%;
  width: 5px;
  height: 45px;
  border-radius: 10px;
  background: #fff;
  box-shadow: 0 0 15px #b5a4ff;
  transition: left .65s cubic-bezier(.2,.8,.2,1);
  z-index: 3;
}

.timing-labels {
  display: flex;
  justify-content: space-between;
  color: #aeb0c9;
  font-size: 11px;
  margin-top: 8px;
}

.timing-value {
  margin-top: 28px;
  font-size: 30px;
  font-weight: 900;
  color: #b9aaff;
  letter-spacing: 2px;
  text-shadow: 0 0 20px rgba(155,140,255,.4);
}

#timingDescription {
  color: #c0c2d6;
  line-height: 2;
  font-size: 13px;
  max-width: 500px;
  margin: 12px auto 0;
  min-height: 52px;
}

@media(max-width:480px) {
  .timing-visual {
    padding: 20px 12px;
  }

  .timing-tab {
    min-width: 70px;
    padding: 11px;
  }

  .timing-labels {
    font-size: 10px;
  }

  .timing-value {
    font-size: 26px;
  }
}

/* DIGITAL HOLOGRAPHIC STIMULI */

.stimulus,
#stimulus,
.arrow-stimulus {
  font-family: Arial, sans-serif !important;
  font-size: clamp(110px, 28vw, 180px) !important;
  font-weight: 900 !important;
  line-height: 1 !important;
  text-align: center;
  color: #a995ff;
  text-shadow:
    0 0 8px #a995ff,
    0 0 22px rgba(169,149,255,.9),
    0 0 48px rgba(169,149,255,.55);
  -webkit-text-stroke: 2px #e4dcff;
}

/* RIGHT AND LEFT ARROWS */
.stimulus.left,
.stimulus.right,
#stimulus.left,
#stimulus.right {
  color: #65efff;
  text-shadow:
    0 0 8px #65efff,
    0 0 25px rgba(101,239,255,.9),
    0 0 55px rgba(101,239,255,.5);
}

/* STOP SIGNAL */
.stop-stimulus,
#stopStimulus {
  width: 105px;
  height: 105px;
  margin: auto;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 7px solid #ff65b5;
  border-radius: 24px;
  background: rgba(255,65,160,.12);
  color: #ff78bd;
  font-size: 65px;
  font-weight: 900;
  box-shadow:
    0 0 12px #ff65b5,
    0 0 35px rgba(255,101,181,.55),
    inset 0 0 20px rgba(255,101,181,.2);
}

/* MOBILE */
@media(max-width:600px) {
  .stimulus,
  #stimulus,
  .arrow-stimulus {
    font-size: 135px !important;
  }
}

/* =================================
   DIGITAL HOLOGRAPHIC ARROWS
================================= */

#practiceStimulus,
#testStimulus {
  width: 100%;
  min-height: 230px;
  display: flex;
  align-items: center;
  justify-content: center;

  font-family: Arial, sans-serif !important;
  font-size: clamp(125px, 32vw, 185px) !important;
  font-weight: 900 !important;
  line-height: 1 !important;

  color: #9e8aff;
  -webkit-text-stroke: 3px #e6ddff;

  text-shadow:
    0 0 5px #ffffff,
    0 0 12px #a995ff,
    0 0 28px #9275ff,
    0 0 55px rgba(146,117,255,.75);

  filter: drop-shadow(0 0 12px rgba(155,130,255,.6));
  transition: color .15s ease, filter .15s ease;
}

/* LEFT AND RIGHT ARROWS */
#practiceStimulus.is-arrow,
#testStimulus.is-arrow {
  color: #75edff;
  -webkit-text-stroke: 3px #e4fcff;

  text-shadow:
    0 0 6px #ffffff,
    0 0 15px #55e7f2,
    0 0 32px #36d8f2,
    0 0 60px rgba(54,216,242,.8);
}

/* STOP SIGNAL - DISTINCT DESIGN */
#practiceStimulus.is-stop,
#testStimulus.is-stop {
  width: 112px;
  min-height: 112px;
  height: 112px;
  margin: 55px auto;

  border: 6px solid #ff65b5;
  border-radius: 25px;

  background:
    linear-gradient(145deg,
      rgba(255,101,181,.25),
      rgba(80,20,75,.55));

  color: #ff8bc8;
  font-size: 48px !important;
  font-weight: 900 !important;
  letter-spacing: 2px;

  -webkit-text-stroke: 0;

  box-shadow:
    0 0 12px #ff65b5,
    0 0 30px rgba(255,101,181,.6),
    inset 0 0 20px rgba(255,101,181,.25);

  text-shadow: 0 0 12px #ff65b5;
}

/* MOBILE */
@media(max-width:600px) {
  #practiceStimulus,
  #testStimulus {
    min-height: 210px;
    font-size: 140px !important;
  }
}
/* ===== FINAL STOP SIGNAL STIMULUS FIX ===== */

#practiceStimulus,
#testStimulus {
  width: 230px;
  height: 190px;
  margin: 18px auto;
  display: flex;
  align-items: center;
  justify-content: center;

  font-family: Arial, sans-serif;
  font-size: clamp(130px, 28vw, 175px);
  font-weight: 900;
  line-height: 1;

  color: #72efff;
  background: radial-gradient(
    circle,
    rgba(75, 225, 255, 0.18),
    rgba(12, 20, 45, 0.35) 72%
  );

  border: 1px solid rgba(101, 239, 255, 0.35);
  border-radius: 25px;

  text-shadow:
    0 0 5px #fff,
    0 0 14px #65efff,
    0 0 30px #36dfff,
    0 0 55px rgba(54, 223, 255, 0.7);

  -webkit-text-stroke: 2px #d9fcff;

  box-shadow:
    inset 0 0 25px rgba(101, 239, 255, 0.1),
    0 0 28px rgba(54, 223, 255, 0.13);

  transition: all 0.18s ease;
}

/* علامت توقف: مربع نئونی مستقل از فلش */
#practiceStimulus.stop,
#testStimulus.stop {
  width: 112px;
  height: 112px;
  min-height: 112px;

  border: 5px solid #ff75b5;
  border-radius: 22px;

  background: rgba(255, 75, 155, 0.13);

  color: #ff8fc2;
  font-family: Arial, sans-serif;
  font-size: 27px;
  font-weight: 900;
  letter-spacing: 2px;

  -webkit-text-stroke: 0;

  text-shadow:
    0 0 10px #ff75b5,
    0 0 25px rgba(255, 75, 155, 0.8);

  box-shadow:
    inset 0 0 20px rgba(255, 75, 155, 0.15),
    0 0 30px rgba(255, 75, 155, 0.3);
}

@media (max-width: 480px) {
  #practiceStimulus,
  #testStimulus {
    width: 205px;
    height: 175px;
    font-size: 135px;
  }
}/* FAST STOP SIGNAL STIMULUS */

#practiceStimulus,
#testStimulus {
  width: 210px;
  height: 180px;
  margin: 12px auto;
  display: flex;
  align-items: center;
  justify-content: center;

  font: 900 clamp(125px, 27vw, 165px)/1 Arial, sans-serif;
  color: #65efff;

  background: rgba(65, 220, 255, 0.06);
  border: 1px solid rgba(101, 239, 255, 0.3);
  border-radius: 20px;

  text-shadow: 0 0 8px rgba(101, 239, 255, 0.65);
  -webkit-text-stroke: 1px #d9fcff;

  box-shadow: 0 0 12px rgba(54, 223, 255, 0.1);
  transition: none !important;
  animation: none !important;
}

/* STOP */
#practiceStimulus.stop,
#testStimulus.stop {
  width: 105px;
  height: 105px;

  border: 5px solid #ff75b5;
  border-radius: 20px;

  background: rgba(255, 75, 155, 0.1);
  color: #ff8fc2;

  font: 900 26px/1 Arial, sans-serif;
  letter-spacing: 2px;

  text-shadow: 0 0 8px rgba(255, 75, 155, 0.7);
  -webkit-text-stroke: 0;
  box-shadow: 0 0 12px rgba(255, 75, 155, 0.15);
}

@media (max-width: 480px) {
  #practiceStimulus,
  #testStimulus {
    width: 190px;
    height: 160px;
    font-size: 130px;
  }
}/* FAST STIMULUS DISPLAY */
#practiceStimulus,
#testStimulus {
  transition: none !important;
  animation: none !important;
  opacity: 1 !important;
  transform: none !important;
}