/* ============================================================
 * FutureLearn — Home (Header + Hero)
 * Version: v1.4.9
 * Mobile-first, dùng min-width để mở rộng
 * ============================================================ */

/* ============================================================
 * HEADER / NAV
 * ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1030;
  background-color: var(--white);
  border-bottom: 1px solid rgba(113, 206, 255, 0.35);
  transition:
    box-shadow 0.25s var(--ease-out),
    border-color 0.25s var(--ease-out);
}

.site-header.is-scrolled {
  box-shadow: var(--shadow-soft);
  border-bottom-color: var(--secondary-cyan);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  min-height: var(--header-height);
  padding-block: 0.5rem;
}

/* Logo (image) */
.site-header__logo {
  display: inline-flex;
  align-items: center;
  text-decoration: none;
  flex-shrink: 0;
  line-height: 0;
}

.site-header__logo-img {
  display: block;
  height: 40px;
  width: auto;
  max-width: 180px;
  object-fit: contain;
  transition: opacity 0.2s var(--ease-out);
}

.site-header__logo:hover {
  color: transparent;
}

.site-header__logo:hover .site-header__logo-img {
  opacity: 0.85;
}

/* Nav (desktop hidden until ≥ 992px) */
.site-header__nav {
  display: none;
}

.site-header__menu {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.site-header__item {
  position: relative;
}

.site-header__link {
  display: inline-block;
  padding: 0.5rem 0.85rem;
  color: var(--natural-black-3);
  font-family: var(--font-body);
  font-size: 0.875rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  border-radius: 6px;
  transition: color 0.2s var(--ease-out);
  position: relative;
}

/* Underline animation — không dùng gradient overlay mặc định */
.site-header__link::after {
  content: "";
  position: absolute;
  left: 0.85rem;
  right: 0.85rem;
  bottom: 0.25rem;
  height: 2px;
  background-color: var(--secondary-cyan);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.25s var(--ease-out);
}

.site-header__link:hover {
  color: var(--primary-blue-1);
}

.site-header__link:hover::after,
.site-header__item.is-active .site-header__link::after {
  transform: scaleX(1);
}

.site-header__item.is-active .site-header__link {
  color: var(--primary-blue-1);
}

/* CTA group (desktop hidden until ≥ 768px) */
.site-header__cta {
  display: none;
  align-items: center;
  gap: 0.5rem;
  flex-shrink: 0;
}

/* Hamburger (mobile) */
.site-header__hamburger {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 0;
  background: transparent;
  border: 1px solid var(--secondary-cyan);
  border-radius: 10px;
  cursor: pointer;
  transition: background-color 0.2s var(--ease-out);
}

.site-header__hamburger:hover {
  background-color: var(--secondary-cyan-light);
}

.site-header__hamburger-bar {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--primary-blue-1);
  border-radius: 2px;
  transition:
    transform 0.25s var(--ease-out),
    opacity 0.2s var(--ease-out);
}

/* Hamburger open state → X */
.site-header__hamburger[aria-expanded="true"]
  .site-header__hamburger-bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.site-header__hamburger[aria-expanded="true"]
  .site-header__hamburger-bar:nth-child(2) {
  opacity: 0;
}

.site-header__hamburger[aria-expanded="true"]
  .site-header__hamburger-bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* Mobile drawer */
.site-header__drawer {
  max-height: calc(100dvh - var(--header-height));
  overflow-y: auto;
  overscroll-behavior: contain;
  border-top: 1px solid rgba(113, 206, 255, 0.35);
  padding: var(--space-3) var(--space-3) var(--space-4);
  background: var(--white);
}

.site-header__drawer-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.site-header__drawer-list a {
  display: block;
  padding: 0.875rem 1rem;
  color: var(--natural-black-3);
  font-weight: 500;
  font-size: 1rem;
  text-transform: uppercase;
  border-radius: 10px;
  transition:
    background-color 0.2s var(--ease-out),
    color 0.2s var(--ease-out);
}

.site-header__drawer-list a:hover {
  background: linear-gradient(
    180deg,
    rgba(95, 196, 255, 0) 0%,
    rgba(95, 196, 255, 0.12) 100%
  );
  color: var(--primary-blue-1);
}

.site-header__drawer-cta {
  display: flex;
  gap: 0.75rem;
  margin-top: var(--space-3);
}

.site-header__drawer-cta .capsule-btn {
  flex: 1;
}

/* Breakpoint ≥ 768px — show CTA group */
@media (min-width: 768px) {
  .site-header__inner {
    padding-block: 0.65rem;
  }

  .site-header__cta {
    display: inline-flex;
  }

  .site-header__logo-img {
    height: 44px;
    max-width: 190px;
  }
}

/* Breakpoint ≥ 1200px — show full nav, hide hamburger + drawer */
@media (min-width: 1200px) {
  .site-header__nav {
    display: block;
  }

  .site-header__hamburger {
    display: none;
  }

  .site-header__drawer {
    display: none;
  }

  .site-header__logo-img {
    height: 48px;
    max-width: 200px;
  }

  .site-header__nav {
    flex: 1;
  }

  .site-header__menu {
    justify-content: center;
  }
}

/* ============================================================
 * HERO
 * ============================================================ */
.hero {
  position: relative;
  height: clamp(36rem, 155vw, 42rem);
  overflow: hidden;
  color: var(--white);
  background-color: #ff9d08;
}

.hero__slide {
  position: absolute;
  inset: 0;
  visibility: hidden;
  opacity: 0;
  background-position: center;
  background-repeat: no-repeat;
  background-size: cover;
  transition:
    opacity 0.8s ease-in-out,
    visibility 0.8s ease-in-out;
}

.hero__slide.is-active {
  z-index: 1;
  visibility: visible;
  opacity: 1;
}

.hero__slide--learning {
  background-color: #ff9d08;
  background-image: url("../images/heros/backg.png");
}

.hero__slide--brand {
  background-color: #058bea;
  background-image: url("../images/heros/backg2.jpg");
}

.hero__inner {
  position: relative;
  width: 100%;
  height: 100%;
  margin-inline: auto;
}

.hero__content {
  position: relative;
  z-index: 3;
  width: 100%;
  padding: clamp(1.75rem, 7vw, 2.5rem) 1rem 0;
  text-align: center;
}

.hero__title,
.hero__highlight {
  margin: 0;
  font-family: var(--font-heading);
  font-weight: 700;
  text-transform: uppercase;
}

.hero__title {
  font-size: clamp(1.85rem, 8.6vw, 2.75rem);
  line-height: 1.02;
  letter-spacing: -0.035em;
  text-shadow: 0 3px 12px rgba(166, 72, 0, 0.2);
}

.hero__highlight {
  display: inline-block;
  max-width: 100%;
  margin-top: 0.75rem;
  padding: 0.5rem 0.8rem 0.62rem;
  color: var(--white);
  font-size: clamp(1.15rem, 6.1vw, 2rem);
  line-height: 1.05;
  letter-spacing: -0.035em;
  white-space: nowrap;
  background: linear-gradient(180deg, #168cff 0%, #0068eb 100%);
  border: 1px solid rgba(255, 255, 255, 0.45);
  border-radius: 0.8rem;
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.35),
    0 8px 20px rgba(0, 92, 220, 0.2);
}

.hero__benefits {
  display: flex;
  flex-wrap: nowrap;
  align-items: center;
  justify-content: center;
  gap: 0.3rem 0.8rem;
  width: min(100%, 22rem);
  margin: 0.8rem auto 0;
  padding: 0;
  list-style: none;
  font-size: clamp(0.5rem, 2.35vw, 0.88rem);
  font-weight: 600;
  line-height: 1.45;
  white-space: nowrap;
  text-shadow: 0 2px 7px rgba(130, 60, 0, 0.3);
}

.hero__benefits li {
  position: relative;
}

.hero__benefits li:not(:last-child)::after {
  content: "";
  position: absolute;
  top: 50%;
  right: -0.52rem;
  width: 0.36rem;
  height: 0.36rem;
  background-color: #ffdc18;
  border-radius: 50%;
  transform: translateY(-50%);
  box-shadow: 0 0 8px rgba(255, 230, 39, 0.75);
}

.hero__cta {
  display: inline-flex;
  align-items: center;
  gap: 0.85rem;
  margin-top: 1rem;
  padding: 0.45rem 0.5rem 0.45rem 1.15rem;
  color: #0865db;
  font-size: clamp(0.95rem, 4vw, 1.15rem);
  font-weight: 700;
  line-height: 1;
  background-color: var(--white);
  border-radius: 999px;
  box-shadow: 0 8px 22px rgba(174, 72, 0, 0.22);
  transition:
    color 0.2s var(--ease-out),
    transform 0.2s var(--ease-out),
    box-shadow 0.2s var(--ease-out);
}

.hero__cta:hover {
  color: #004fbd;
  transform: translateY(-2px);
  box-shadow: 0 12px 26px rgba(174, 72, 0, 0.28);
}

.hero__cta:focus-visible {
  outline: 3px solid var(--white);
  outline-offset: 4px;
}

.hero__cta-icon {
  display: inline-grid;
  flex: 0 0 auto;
  width: 2.45rem;
  height: 2.45rem;
  place-items: center;
  color: var(--white);
  background: linear-gradient(180deg, #268fff 0%, #0068eb 100%);
  border-radius: 50%;
}

.hero__artwork {
  position: absolute;
  inset: 0;
  z-index: 2;
  pointer-events: none;
}

.hero__character {
  position: absolute;
  display: block;
  max-width: none;
  height: auto;
  object-fit: contain;
  user-select: none;
}

.hero__character--student {
  z-index: 2;
  right: 0;
  bottom: 0.5rem;
  width: min(56vw, 15.5rem);
}

/* Robot chỉ xuất hiện từ tablet/desktop; mobile giữ một mình bé tốt nghiệp. */
.hero__character--robot {
  display: none;
}

.hero__brand-artwork {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.hero__brand-logo,
.hero__brand-people {
  position: absolute;
  display: block;
  max-width: none;
  height: auto;
  object-fit: contain;
  user-select: none;
}

.hero__brand-logo {
  z-index: 1;
  top: 0;
  left: 50%;
  width: min(72vw, 30rem);
  transform: translateX(-50%);
}

.hero__brand-people {
  z-index: 2;
  right: 50%;
  bottom: -8%;
  width: min(80vw, 27rem);
  transform: translateX(50%);
}

.hero__brand-content {
  position: absolute;
  top: 25%;
  right: 1rem;
  left: 1rem;
  z-index: 3;
  color: var(--white);
  text-align: center;
  text-shadow: 0 3px 12px rgba(0, 66, 173, 0.3);
}

.hero__brand-title,
.hero__brand-description {
  margin: 0;
}

.hero__brand-title {
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 6.8vw, 2rem);
  font-weight: 700;
  line-height: 1.08;
  letter-spacing: -0.025em;
}

.hero__brand-description {
  margin-top: 0.45rem;
  font-size: clamp(0.78rem, 3.4vw, 1rem);
  font-weight: 500;
  line-height: 1.35;
}

.hero__brand-cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  min-width: min(76vw, 17rem);
  margin-top: 0.85rem;
  padding: 0.8rem 1.25rem;
  color: var(--white);
  font-size: clamp(0.95rem, 4.2vw, 1.15rem);
  font-weight: 700;
  line-height: 1;
  text-shadow: none;
  background: linear-gradient(180deg, #ffb31a 0%, #ff6900 100%);
  border: 2px solid rgba(255, 225, 91, 0.85);
  border-radius: 999px;
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.35),
    0 8px 22px rgba(0, 73, 190, 0.28);
  transition:
    transform 0.2s var(--ease-out),
    box-shadow 0.2s var(--ease-out);
}

.hero__brand-cta:hover {
  color: var(--white);
  transform: translateY(-2px);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.35),
    0 12px 28px rgba(0, 73, 190, 0.36);
}

.hero__brand-cta:focus-visible {
  outline: 3px solid var(--white);
  outline-offset: 4px;
}

@media (max-width: 767.98px) {
  .hero__benefits {
    gap: 0.3rem 0.45rem;
    width: calc(100% + 1.5rem);
    margin-right: -0.75rem;
    margin-left: -0.75rem;
    font-size: clamp(0.66rem, 3.15vw, 0.84rem);
    font-weight: 700;
    letter-spacing: -0.045em;
  }

  .hero__benefits li:not(:last-child)::after {
    right: -0.31rem;
    width: 0.28rem;
    height: 0.28rem;
  }

  .hero__character--student {
    top: 24%;
    right: 50%;
    bottom: auto;
    width: min(78vw, 19.5rem);
    transform: translateX(50%);
  }

  .hero__brand-logo {
    top: 8%;
    width: min(78vw, 32rem);
  }

  .hero__brand-people {
    bottom: -5%;
    width: min(86vw, 29rem);
  }
}

@media (min-width: 768px) {
  .hero {
    height: clamp(30rem, 46vw, 34.5rem);
  }

  .hero__content {
    position: absolute;
    top: 12%;
    left: 6%;
    width: 55%;
    padding: 0;
    text-align: left;
  }

  .hero__title {
    font-size: clamp(2.35rem, 4.55vw, 4.5rem);
    white-space: nowrap;
  }

  .hero__highlight {
    margin-top: 0.6rem;
    padding: 0.45rem 0.95rem 0.62rem;
    font-size: clamp(1.85rem, 3.65vw, 3.5rem);
    border-radius: 1rem;
  }

  .hero__benefits {
    justify-content: flex-start;
    gap: 0.35rem 1.35rem;
    width: 100%;
    margin-top: 0.7rem;
    margin-right: 0;
    margin-left: 0;
    font-size: clamp(0.72rem, 1.28vw, 1.2rem);
  }

  .hero__benefits li:not(:last-child)::after {
    right: -0.82rem;
  }

  .hero__cta {
    margin-top: 1.2rem;
    padding-left: 1.45rem;
    font-size: clamp(1rem, 1.6vw, 1.4rem);
  }

  .hero__cta-icon {
    width: clamp(2.5rem, 3.5vw, 3.25rem);
    height: clamp(2.5rem, 3.5vw, 3.25rem);
  }

  .hero__character--student {
    top: 0;
    right: 2.5%;
    bottom: auto;
    width: 33%;
  }

  .hero__character--robot {
    z-index: 1;
    bottom: -2%;
    left: 43%;
    display: block;
    width: 39%;
    transform: translateX(-50%);
  }

  .hero__brand-logo {
    top: 5%;
    /* Bù khoảng trong suốt bên trái PNG để mép logo thẳng với copy ở 8%. */
    left: 29%;
    width: 48%;
  }

  .hero__brand-content {
    top: 40%;
    right: auto;
    left: 8%;
    width: 50%;
    text-align: left;
    text-shadow: 0 3px 12px rgba(0, 54, 150, 0.55);
  }

  .hero__brand-title {
    font-size: clamp(2.2rem, 3.3vw, 4.1rem);
    white-space: nowrap;
  }

  .hero__brand-description {
    margin-top: 0.45rem;
    font-size: clamp(1.05rem, 1.7vw, 2.05rem);
    white-space: nowrap;
  }

  .hero__brand-cta {
    min-width: min(64%, 32rem);
    margin-top: 1.2rem;
    padding: clamp(0.75rem, 1.15vw, 1.15rem) 2rem;
    font-size: clamp(1.25rem, 2vw, 2.35rem);
  }

  .hero__brand-people {
    right: 2.5%;
    bottom: -5%;
    width: auto;
    height: 105%;
    transform: none;
  }
}

@media (min-width: 1200px) {
  .hero__slide {
    /* Desktop: kéo giãn từng nền theo toàn bộ kích thước hero. */
    background-size: 100% 100%;
  }

  .hero {
    height: min(40.5vw, 800px);
  }

  .hero__inner {
    width: min(100%, 1998px);
  }

  .hero__content {
    top: 16%;
    left: 8%;
    width: 52%;
  }

  .hero__title {
    font-size: clamp(3.25rem, 4.55vw, 5.65rem);
  }

  .hero__highlight {
    font-size: clamp(2.55rem, 3.9vw, 4.7rem);
    border-radius: clamp(1rem, 1.5vw, 1.8rem);
  }

  .hero__benefits {
    margin-top: 0.85rem;
    font-size: clamp(0.92rem, 1.25vw, 1.5rem);
  }

  .hero__cta {
    margin-top: 1.45rem;
    padding-left: clamp(1.5rem, 2vw, 2.35rem);
    font-size: clamp(1.1rem, 1.45vw, 1.75rem);
  }

  .hero__character--student {
    top: -3%;
    right: 4.5%;
    bottom: auto;
    width: 27.5%;
  }

  .hero__character--robot {
    bottom: -4%;
    left: 44.5%;
    width: 39%;
  }

  .hero__brand-people {
    right: 7%;
    bottom: -21%;
    height: 135%;
  }
}

@media (prefers-reduced-motion: reduce) {
  .hero__slide {
    transition: none;
  }

  .hero__cta {
    transition: none;
  }

  .hero__brand-cta {
    transition: none;
  }
}