/* =========================
SECTIONS (EXPERIENCE / CONTENT)
========================= */

.start-section,
.move-section {
background: linear-gradient(180deg, #162f45 0%, #1d3a52 100%);
color: #fff;
}

.section {
padding: 80px 0;
background: var(--bg);
}

/* =========================
CONTENT SYSTEM
========================= */

.content-section {
  position: relative;

  overflow: hidden;
}

.content-section .container {
  position: relative;
  z-index: 2;
}

/* =========================
CONTENT RHYTHM
========================= */

.content-section {
  position: relative;
  overflow: hidden;
  padding: 80px 0;

}

.content-section:first-of-type {
  padding-top: 80px;
}

.content-section:last-of-type {
  padding-bottom: 140px;
}

/* =========================
   LESSON SCREEN RHYTHM — DESKTOP / TABLET
   one lesson section = one viewport scene
========================= */

@media (min-width: 901px) {
  .lesson-hero.content-section,
  .section.content-section,
  .section.next-section {
    min-height: 100svh;

    display: flex;
    align-items: center;
  }

  .lesson-hero.content-section > .container,
  .section.content-section > .container,
  .section.next-section > .container {
    width: min(1200px, calc(100% - 40px));
  }
}

/* =========================
CONTENT LIGHT RHYTHM
========================= */

.content-section::before {
  content: "";

  position: absolute;

  inset: 0;

  pointer-events: none;

  background:
    radial-gradient(
      circle at top,
      rgba(255,255,255,0.55),
      transparent 65%
    );

  opacity: 0.7;
}

.content-section:nth-of-type(even)::before {
  opacity: 0.38;
}

/* =========================
CONTENT BACKDROP ATMOSPHERE
========================= */

.content-section::after {
  content: "";

  position: absolute;

  inset: 0;

  pointer-events: none;

  background:
    linear-gradient(
      180deg,
      rgba(255,255,255,0.00) 0%,
      rgba(255,255,255,0.32) 100%
    );

  opacity: 0.7;

  z-index: 1;
}

/* =========================
   LESSON EFFECT
========================= */

.lesson-effect-section {
  background: var(--bg);
}

.lesson-effect-box {
  max-width: 760px;
  margin: 0 auto;
  padding: clamp(34px, 5vw, 58px);
  text-align: center;
}

.lesson-effect-box h2 {
  margin: 22px 0 16px;

  font-size: clamp(28px, 3.2vw, 42px);
  line-height: 0.95;
  letter-spacing: -0.05em;

  color: rgba(15,23,42,0.94);
}

.lesson-effect-box p {
  max-width: 580px;
  margin: 0 auto;

  font-size: 18px;
  line-height: 1.75;

  color: rgba(15,23,42,0.68);
}

/* =========================
INTEGRATION / PAUSE
========================= */

.integration-section {
  background:
    radial-gradient(
      circle at 20% 20%,
      rgba(255,225,68,0.12),
      transparent 34%
    ),
    linear-gradient(
      180deg,
      rgba(246,242,231,0.96),
      rgba(232,226,210,0.94)
    );
}

.integration-box {
  max-width: 920px;
  margin: 0 auto;

  display: grid;
  grid-template-columns: minmax(220px, 0.85fr) minmax(0, 1.15fr);

  padding: 0;

  overflow: hidden;

  background:
    linear-gradient(
      180deg,
      rgba(18,35,55,0.96),
      rgba(10,22,36,0.98)
    );

  border:
    1px solid rgba(255,255,255,0.10);

  color:
    #f4f7fb;

  box-shadow:
    0 34px 90px rgba(15,23,42,0.22),
    inset 0 1px 0 rgba(255,255,255,0.08);
}

.integration-visual {
  position: relative;

  min-height: 100%;

  overflow: hidden;

  background:
    rgba(255,225,68,0.08);
}

.integration-visual::after {
  content: "";

  position: absolute;
  inset: 0;

  background:
    linear-gradient(
      90deg,
      rgba(10,22,36,0.04),
      rgba(10,22,36,0.78)
    ),
    radial-gradient(
      circle at 30% 28%,
      rgba(255,225,68,0.18),
      transparent 42%
    );

  pointer-events: none;
}

.integration-visual img {
  width: 100%;
  height: 100%;

  min-height: 340px;

  object-fit: cover;
  object-position: center;

  display: block;

  filter:
    saturate(0.95)
    contrast(1.04);
}

.integration-content {
  padding: clamp(34px, 5vw, 58px);

  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: flex-start;

  text-align: left;
}

.integration-content .section-label {
  margin-bottom: 34px;
}

.integration-content .integration-label {
  margin-bottom: 2.2rem;
  align-self: flex-start;
  transform: translateY(-0.75rem);
}

.integration-content h2 {
  margin: 0 0 20px;

  max-width: 620px;

  font-size: clamp(32px, 4vw, 54px);
  line-height: 0.94;
  letter-spacing: -0.055em;

  color:
    #f4f7fb;
}

.integration-content p {
  max-width: 600px;

  margin: 0 0 14px;

  font-size: 17px;
  line-height: 1.78;

  color:
    rgba(255,255,255,0.68);
}

.integration-content p:last-child {
  margin-bottom: 0;
}

@media (max-width: 768px) {
  .integration-box {
    grid-template-columns: 1fr;
  }

  .integration-visual img {
    min-height: 190px;
    max-height: 240px;
  }

  .integration-visual::after {
    background:
      linear-gradient(
        180deg,
        rgba(10,22,36,0.02),
        rgba(10,22,36,0.68)
      );
  }

  .integration-content {
    padding: 34px 26px 38px;
  }

  .integration-content h2 {
    font-size: clamp(34px, 10vw, 48px);
  }

  .integration-content p {
    font-size: 16px;
  }
}

/* =========================
   SECTION BACKGROUND VISUAL
========================= */

.section-bg-visual {
  position: absolute;
  inset: 0;

  width: 100%;
  height: 100%;

  opacity: 0.12;

  pointer-events: none;
  z-index: 1;
}

.section-bg-visual img {
  width: 100%;
  height: 100%;

  object-fit: cover;
  object-position: center;

  display: block;
}

/* =========================
   INTEGRATION PAUSE — SOFT BORDER LIGHT
   calm animated border glow for pause section
========================= */

.integration-box {
  position: relative;
  isolation: isolate;
}

.integration-box::before {
  content: "";

  position: absolute;
  inset: -1px;

  border-radius: inherit;

  pointer-events: none;
  z-index: 2;

  background:
    linear-gradient(
      120deg,
      transparent 0%,
      rgba(255, 225, 68, 0.00) 28%,
      rgba(255, 225, 68, 0.44) 48%,
      rgba(255, 255, 255, 0.32) 52%,
      rgba(255, 225, 68, 0.00) 72%,
      transparent 100%
    );

  background-size: 260% 260%;

  opacity: 0.58;

  mask:
    linear-gradient(#000 0 0) content-box,
    linear-gradient(#000 0 0);
  mask-composite: exclude;

  -webkit-mask:
    linear-gradient(#000 0 0) content-box,
    linear-gradient(#000 0 0);
  -webkit-mask-composite: xor;

  padding: 1px;

  animation:
    integrationBorderLight 8s linear infinite;
}

.integration-visual::before {
  content: "";

  position: absolute;

  width: 16px;
  height: 16px;

  top: 72%;
  left: 72%;

  border-radius: 999px;

  pointer-events: none;
  z-index: 3;

  background:
    radial-gradient(
      circle,
      rgba(255, 247, 196, 0.95) 0%,
      rgba(255, 225, 68, 0.58) 34%,
      rgba(255, 225, 68, 0.00) 74%
    );

  box-shadow:
    0 0 18px rgba(255, 225, 68, 0.42),
    0 0 42px rgba(255, 225, 68, 0.20);

  opacity: 0.62;

  animation:
    integrationImageLightFloat 18s ease-in-out infinite;
}

@keyframes integrationBorderLight {
  0% {
    background-position: 0% 50%;
    opacity: 0.34;
  }

  45% {
    opacity: 0.64;
  }

  100% {
    background-position: 260% 50%;
    opacity: 0.34;
  }
}

@keyframes integrationImageLightFloat {
  0% {
    top: 74%;
    left: 72%;
    transform: translate(0, 0) scale(0.90);
    opacity: 0.34;
  }

  14% {
    top: 48%;
    left: 62%;
    transform: translate(10px, -8px) scale(1.02);
    opacity: 0.54;
  }

  28% {
    top: 24%;
    left: 46%;
    transform: translate(-6px, -10px) scale(1.08);
    opacity: 0.68;
  }

  44% {
    top: 18%;
    left: 24%;
    transform: translate(8px, 6px) scale(0.96);
    opacity: 0.48;
  }

  60% {
    top: 42%;
    left: 18%;
    transform: translate(-4px, 8px) scale(1.04);
    opacity: 0.62;
  }

  78% {
    top: 82%;
    left: 30%;
    transform: translate(6px, -4px) scale(0.94);
    opacity: 0.42;
  }

  100% {
    top: 74%;
    left: 72%;
    transform: translate(0, 0) scale(0.90);
    opacity: 0.34;
  }
}

@media (prefers-reduced-motion: reduce) {
  .integration-box::before,
  .integration-visual::before {
    animation: none;
  }
}