:root {
  --bg-main: #0b0715;
  --bg-soft: #141024;
  --text-main: #f4efff;
  --text-soft: #d2c5f3;
  --purple: #8b5cf6;
  --purple-2: #a855f7;
  --cyan: #22d3ee;
  --pink: #ec4899;
  --line: rgba(255, 255, 255, 0.12);
  --glass: rgba(255, 255, 255, 0.08);
  --shadow: 0 20px 60px rgba(0, 0, 0, 0.35);
  --radius-xl: 28px;
  --radius-lg: 22px;
  --radius-md: 16px;
  --container: 1200px;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: "Montserrat", sans-serif;
  color: var(--text-main);
  background:
    radial-gradient(circle at top left, rgba(139, 92, 246, 0.20), transparent 25%),
    radial-gradient(circle at top right, rgba(34, 211, 238, 0.10), transparent 20%),
    linear-gradient(180deg, #0b0715 0%, #120d20 50%, #0b0715 100%);
  min-height: 100vh;
  overflow-x: hidden;
}

a {
  text-decoration: none;
  color: inherit;
}

button,
input {
  font: inherit;
}

.container {
  width: min(var(--container), calc(100% - 32px));
  margin: 0 auto;
}

.bg-shape {
  position: fixed;
  border-radius: 50%;
  filter: blur(60px);
  z-index: -1;
  pointer-events: none;
  opacity: 0.6;
}

.bg-shape-1 {
  top: 60px;
  left: -70px;
  width: 260px;
  height: 260px;
  background: rgba(168, 85, 247, 0.25);
}
.teacher-name{
margin-top:10px;
font-size:20px;
color:#c4b5fd;
font-weight:600;
letter-spacing:1px;
}

.bg-shape-2 {
  top: 35%;
  right: -100px;
  width: 360px;
  height: 360px;
  background: rgba(34, 211, 238, 0.16);
}

.bg-shape-3 {
  bottom: 0;
  left: 12%;
  width: 280px;
  height: 280px;
  background: rgba(236, 72, 153, 0.14);
}

.glass-card {
  background: linear-gradient(180deg, rgba(255,255,255,0.10), rgba(255,255,255,0.05));
  border: 1px solid var(--line);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  box-shadow: var(--shadow);
}

.hero {
  min-height: 100vh;
  position: relative;
  display: flex;
  align-items: center;
  overflow: hidden;
  background:
    linear-gradient(135deg, rgba(22, 8, 39, 0.45), rgba(8, 8, 18, 0.72)),
    radial-gradient(circle at center, rgba(139, 92, 246, 0.14), transparent 35%);
  background-attachment: fixed;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(180deg, rgba(11, 7, 21, 0.15), rgba(11, 7, 21, 0.55)),
    url("https://images.unsplash.com/photo-1532187863486-abf9dbad1b69?auto=format&fit=crop&w=1600&q=80") center/cover no-repeat;
  opacity: 0.35;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(100, 35, 181, 0.35), rgba(19, 24, 44, 0.55));
}

.hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  padding: 120px 0 70px;
}

.top-badge,
.section-badge,
.small-badge {
  display: inline-block;
  padding: 10px 16px;
  border-radius: 999px;
  border: 1px solid rgba(255,255,255,0.14);
  background: rgba(255,255,255,0.08);
  font-size: 0.85rem;
  font-weight: 700;
}

.hero h1 {
  font-size: clamp(2.8rem, 7vw, 5.4rem);
  margin: 22px 0 16px;
  line-height: 0.95;
}

.hero-text {
  max-width: 800px;
  margin: 0 auto;
  color: var(--text-soft);
  line-height: 1.8;
  font-size: 1.05rem;
}

.hero-buttons {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 28px;
}

.btn {
  display: inline-flex;
  justify-content: center;
  align-items: center;
  padding: 14px 22px;
  border-radius: 16px;
  font-weight: 700;
  border: none;
  cursor: pointer;
  transition: 0.25s ease;
}

.btn:hover {
  transform: translateY(-2px);
}

.btn-primary {
  color: #fff;
  background: linear-gradient(135deg, var(--purple), var(--purple-2));
  box-shadow: 0 12px 32px rgba(139, 92, 246, 0.35);
}

.btn-secondary {
  color: #fff;
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.14);
}

.hero-cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
  margin-top: 42px;
}

.mini-card {
  padding: 22px;
  border-radius: 22px;
}

.mini-card h3 {
  font-size: 2rem;
  margin-bottom: 8px;
}

.mini-card p {
  color: var(--text-soft);
}

.section {
  padding: 90px 0;
}

.section-dark {
  background: linear-gradient(180deg, rgba(255,255,255,0.02), rgba(255,255,255,0.01));
}

.parallax-section {
  background-attachment: fixed;
}

.section-header {
  margin-bottom: 38px;
}

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

.section-header h1,
.section-header h2 {
  font-size: clamp(2rem, 4vw, 3.2rem);
  margin: 16px 0 14px;
  line-height: 1.1;
}

.section-header p {
  color: var(--text-soft);
  line-height: 1.8;
  max-width: 850px;
  margin-inline: auto;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}

.feature-card {
  padding: 28px;
  border-radius: var(--radius-xl);
  transition: 0.3s ease;
}

.feature-card:hover {
  transform: translateY(-6px);
}

.feature-icon {
  font-size: 2rem;
  margin-bottom: 14px;
}

.feature-card h3 {
  margin-bottom: 10px;
}

.feature-card p {
  color: var(--text-soft);
  line-height: 1.8;
}

.grid-2 {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 24px;
  align-items: start;
}

.calculator-box,
.formula-box,
.selected-element-panel,
.periodic-wrapper,
.lab-card,
.photo-card {
  border-radius: var(--radius-xl);
}

.calculator-box {
  padding: 24px;
}

.calc-display {
  width: 100%;
  height: 78px;
  border-radius: 18px;
  border: 1px solid rgba(255,255,255,0.1);
  background: rgba(0,0,0,0.25);
  color: #fff;
  font-size: 2rem;
  font-weight: 700;
  text-align: right;
  padding: 16px 18px;
  margin-bottom: 16px;
}

.calc-buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
}

.calc-btn {
  min-height: 58px;
  border: 1px solid rgba(255,255,255,0.10);
  border-radius: 16px;
  background: rgba(255,255,255,0.08);
  color: #fff;
  cursor: pointer;
  font-weight: 700;
  font-size: 1.05rem;
  transition: 0.2s ease;
}

.calc-btn:hover {
  transform: scale(1.03);
}

.calc-btn.operator {
  background: rgba(139, 92, 246, 0.18);
}

.calc-btn.action {
  background: rgba(34, 211, 238, 0.14);
}

.calc-btn.equal {
  background: linear-gradient(135deg, var(--pink), var(--purple));
}

.calc-btn.wide {
  grid-column: span 2;
}

.calc-btn.full-width {
  grid-column: 1 / -1;
}

.formula-box {
  padding: 28px;
}

.formula-box h3 {
  margin: 18px 0 14px;
  font-size: 1.5rem;
}

.formula-box ul {
  padding-left: 20px;
  margin-bottom: 16px;
}

.formula-box li {
  color: var(--text-soft);
  margin-bottom: 12px;
  line-height: 1.75;
}

.formula-box p {
  color: var(--text-soft);
  line-height: 1.8;
}

.selected-element-panel {
  padding: 22px;
  margin-bottom: 22px;
  display: flex;
  justify-content: space-between;
  gap: 20px;
  align-items: center;
}

.selected-element-panel p {
  color: var(--text-soft);
  line-height: 1.7;
}

.selected-element-card {
  min-width: 140px;
  aspect-ratio: 1;
  border-radius: 22px;
  background: linear-gradient(135deg, rgba(168,85,247,0.28), rgba(34,211,238,0.12));
  border: 1px solid rgba(255,255,255,0.12);
  display: grid;
  place-items: center;
  text-align: center;
  padding: 12px;
}

.selected-element-card span {
  font-size: 0.9rem;
}

.selected-element-card strong {
  font-size: 2.1rem;
  line-height: 1;
}

.selected-element-card small {
  color: var(--text-soft);
}

.periodic-wrapper {
  padding: 16px;
  overflow-x: auto;
}

.periodic-table {
  min-width: 1120px;
  display: grid;
  grid-template-columns: repeat(18, 1fr);
  grid-template-rows: repeat(9, 82px);
  gap: 8px;
}

.element {
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: 14px;
  background: rgba(255,255,255,0.07);
  color: #fff;
  padding: 8px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  cursor: pointer;
  transition: 0.2s ease;
}

.element:hover {
  background: rgba(139, 92, 246, 0.18);
  transform: translateY(-3px);
}

.element .num {
  font-size: 0.72rem;
  color: var(--text-soft);
}

.element .sym {
  font-size: 1.08rem;
  font-weight: 800;
}

.element .name {
  font-size: 0.62rem;
  color: var(--text-soft);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.labs-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 22px;
}

.lab-card {
  padding: 28px;
}

.lab-number {
  font-size: 3rem;
  font-weight: 800;
  opacity: 0.16;
  margin-bottom: 10px;
}

.lab-card h3 {
  margin-bottom: 12px;
}

.lab-card p {
  color: var(--text-soft);
  line-height: 1.8;
  margin-bottom: 18px;
}

.footer {
  border-top: 1px solid rgba(255,255,255,0.08);
  padding: 28px 0 36px;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  color: var(--text-soft);
}

.modal {
  position: fixed;
  inset: 0;
  display: none;
  z-index: 999;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.modal.active {
  display: flex;
}

.modal-overlay {
  position: absolute;
  inset: 0;
  background: rgba(7, 6, 14, 0.72);
  backdrop-filter: blur(8px);
}

.modal-box {
  position: relative;
  z-index: 2;
  width: min(900px, 100%);
  max-height: 90vh;
  overflow-y: auto;
  padding: 32px;
  border-radius: 28px;
}

.modal-close {
  position: absolute;
  top: 16px;
  right: 16px;
  width: 46px;
  height: 46px;
  border: none;
  border-radius: 50%;
  background: rgba(255,255,255,0.08);
  color: #fff;
  font-size: 1.6rem;
  cursor: pointer;
}

.modal-box h2 {
  margin: 16px 0 22px;
  line-height: 1.25;
}

.modal-block {
  margin-bottom: 22px;
}

.modal-block h3 {
  margin-bottom: 12px;
}

.modal-block p,
.modal-block li {
  color: var(--text-soft);
  line-height: 1.85;
}

.modal-block ol {
  padding-left: 22px;
}

.equation-box {
  padding: 16px 18px;
  border-radius: 18px;
  background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.08);
}

.page-glow {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 220px;
  background: radial-gradient(circle at center, rgba(139,92,246,0.24), transparent 60%);
  filter: blur(20px);
  z-index: -1;
  pointer-events: none;
}

.photo-page {
  padding: 80px 0;
}

.back-row {
  margin-bottom: 22px;
}

.photo-grid {
  display: grid;
  gap: 22px;
}

.photo-grid.single {
  grid-template-columns: 1fr;
}

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

.photo-card {
  overflow: hidden;
}

.photo-demo {
  min-height: 360px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 18px;
  padding: 20px;
}

.photo-demo-red {
  background: radial-gradient(circle at center, rgba(255, 70, 70, 0.22), rgba(76, 10, 20, 0.95));
}

.photo-demo-yellow {
  background: radial-gradient(circle at center, rgba(255, 214, 77, 0.24), rgba(84, 58, 0, 0.95));
}

.photo-demo-gold {
  background: radial-gradient(circle at center, rgba(255, 221, 87, 0.22), rgba(53, 37, 7, 0.95));
}

.tube {
  width: 105px;
  height: 230px;
  border: 4px solid rgba(255,255,255,0.55);
  border-radius: 0 0 38px 38px;
  position: relative;
  background: rgba(255,255,255,0.08);
  overflow: hidden;
  box-shadow: inset 0 0 18px rgba(255,255,255,0.08), 0 18px 36px rgba(0,0,0,0.28);
}

.tube::before {
  content: "";
  position: absolute;
  right: 12px;
  top: 0;
  width: 10px;
  height: 100%;
  background: rgba(255,255,255,0.18);
}

.tube-red::after,
.tube-yellow::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 60%;
}

.tube-red::after {
  background: linear-gradient(180deg, rgba(180, 25, 45, 0.92), rgba(108, 7, 18, 0.98));
}

.tube-yellow::after {
  background: linear-gradient(180deg, rgba(255, 221, 87, 0.96), rgba(220, 168, 16, 0.98));
}

.gold-rain {
  width: 180px;
  height: 220px;
  position: relative;
}

.gold-rain::before,
.gold-rain::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(circle, rgba(255,230,120,0.95) 0 3px, transparent 4px),
    radial-gradient(circle, rgba(255,210,40,0.9) 0 4px, transparent 5px),
    radial-gradient(circle, rgba(255,245,180,0.95) 0 2px, transparent 3px);
  background-size: 36px 36px, 50px 50px, 26px 26px;
  background-position: 0 0, 10px 12px, 20px 20px;
}
.page-glow-blue {
  background: radial-gradient(circle at center, rgba(34, 211, 238, 0.24), transparent 60%);
}

.photo-demo-cyan {
  background: radial-gradient(circle at center, rgba(34, 211, 238, 0.22), rgba(7, 38, 58, 0.96));
}

.photo-demo-ice {
  background: radial-gradient(circle at center, rgba(125, 211, 252, 0.20), rgba(8, 29, 50, 0.96));
}

.reaction-flow {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 14px;
  flex-wrap: wrap;
  padding: 20px;
}

.molecule-card {
  min-width: 120px;
  padding: 18px 16px;
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.10);
  border: 1px solid rgba(255, 255, 255, 0.16);
  text-align: center;
  font-weight: 700;
  color: #e8fbff;
  box-shadow: 0 10px 24px rgba(0, 0, 0, 0.20);
}

.reaction-arrow {
  font-size: 2rem;
  font-weight: 800;
  color: #7dd3fc;
}

.tube-lab {
  width: 110px;
  height: 240px;
  border: 4px solid rgba(255,255,255,0.55);
  border-radius: 0 0 38px 38px;
  position: relative;
  background: rgba(255,255,255,0.08);
  overflow: hidden;
  box-shadow: inset 0 0 18px rgba(255,255,255,0.08), 0 18px 36px rgba(0,0,0,0.28);
}

.tube-lab::before {
  content: "";
  position: absolute;
  right: 12px;
  top: 0;
  width: 10px;
  height: 100%;
  background: rgba(255,255,255,0.18);
}

.tube-liquid {
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 58%;
}

.tube-liquid-blue {
  background: linear-gradient(180deg, rgba(56, 189, 248, 0.90), rgba(8, 145, 178, 0.96));
}

.bubble {
  position: absolute;
  border-radius: 50%;
  background: rgba(255,255,255,0.40);
}

.bubble-1 {
  width: 10px;
  height: 10px;
  left: 28px;
  bottom: 70px;
}

.bubble-2 {
  width: 7px;
  height: 7px;
  left: 52px;
  bottom: 110px;
}

.bubble-3 {
  width: 12px;
  height: 12px;
  left: 62px;
  bottom: 88px;
}

.ice-cubes {
  display: flex;
  gap: 10px;
  margin-top: 10px;
}

.ice-cubes span {
  width: 28px;
  height: 28px;
  border-radius: 8px;
  background: rgba(186, 230, 253, 0.35);
  border: 1px solid rgba(255,255,255,0.22);
  box-shadow: inset 0 0 12px rgba(255,255,255,0.18);
}

@media (max-width: 560px) {
  .reaction-flow {
    gap: 10px;
  }

  .molecule-card {
    min-width: 100px;
    padding: 14px 12px;
    font-size: 0.9rem;
  }

  .reaction-arrow {
    font-size: 1.5rem;
  }

  .tube-lab {
    width: 86px;
    height: 190px;
  }
}
.photo-title {
  padding: 10px 16px;
  border-radius: 999px;
  background: rgba(255,255,255,0.10);
  border: 1px solid rgba(255,255,255,0.16);
  font-weight: 700;
}

.photo-content {
  padding: 22px;
}

.photo-content h3 {
  margin-bottom: 10px;
}

.photo-content p {
  color: var(--text-soft);
  line-height: 1.8;
}

@media (max-width: 1100px) {
  .grid-2 {
    grid-template-columns: 1fr;
  }

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

@media (max-width: 860px) {
  .hero {
    background-attachment: scroll;
  }

  .hero-cards,
  .features-grid,
  .labs-grid,
  .photo-grid.double {
    grid-template-columns: 1fr;
  }

  .selected-element-panel {
    flex-direction: column;
    align-items: flex-start;
  }

  .selected-element-card {
    max-width: 180px;
    width: 100%;
  }

  .footer-inner {
    flex-direction: column;
  }
}
.modal-block ol li {
  margin-bottom: 10px;
}

.modal-box .btn {
  margin-top: 10px;
}
@media (max-width: 560px) {
  .container {
    width: min(100% - 20px, var(--container));
  }

  .section {
    padding: 70px 0;
  }

  .hero-content {
    padding-top: 110px;
  }

  .hero-buttons {
    flex-direction: column;
  }

  .btn {
    width: 100%;
  }

  .calculator-box,
  .formula-box,
  .feature-card,
  .lab-card {
    padding: 20px;
  }

  .calc-display {
    font-size: 1.6rem;
    height: 70px;
  }

  .calc-btn {
    min-height: 54px;
  }

  .photo-demo {
    min-height: 280px;
  }

  .tube {
    width: 86px;
    height: 185px;
  }

  .modal-box {
    padding: 24px 18px;
  }
}