/* ==========================================================
   HollowLight — Hero Curtain
   Full-viewport curtain with typewriter + Ken Burns bg
   ========================================================== */

/* ---- Curtain Container ---- */
.hl-curtain {
  position: relative;
  height: 100vh;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--hl-black);  /* 图片加载前 / 失败时的降级背景 */
}

.hl-curtain.curtain--hidden {
  display: none;
}

/* ---- Background Layer ---- */
.curtain-bg-wrap {
  position: absolute;
  inset: 0;
}

.curtain-bg--img {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  animation: curtain-zoom 20s ease-in-out infinite alternate;
}

.curtain-bg--video {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* ---- Overlay: gradient fades to #000 at bottom ---- */
.curtain-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(
    to bottom,
    rgba(0, 0, 0, 0.3) 0%,
    rgba(0, 0, 0, 0.15) 40%,
    rgba(0, 0, 0, 0.6) 80%,
    #000 100%
  );
}

/* ---- Content Body ---- */
.curtain-body {
  position: relative;
  z-index: 1;
  text-align: center;
  padding: 0 24px;
}

/* ---- Title ---- */
.curtain-title {
  font-size: clamp(2.4rem, 6vw, 4.8rem);
  font-weight: 900;
  color: #fff;
  letter-spacing: 0.1em;
  margin: 0 0 20px;
  text-shadow: 0 2px 30px rgba(0, 0, 0, 0.5);
  animation: curtain-fade-up 0.9s ease 0.2s both;
}

/* ---- Typewriter ---- */
.curtain-tw {
  font-size: clamp(1rem, 2.5vw, 1.4rem);
  color: var(--hl-accent);
  height: 2.2em;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 3px;
  animation: curtain-fade-up 0.9s ease 0.5s both;
}

.curtain-tw-cursor {
  display: inline-block;
  width: 2px;
  height: 1.2em;
  background: var(--hl-accent);
  vertical-align: middle;
  border-radius: 1px;
  animation: curtain-cursor-blink 0.8s steps(1) infinite;
}

/* ---- Scroll Button ---- */
.curtain-scroll-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  margin-top: 52px;
  background: none;
  border: none;
  color: rgba(255, 255, 255, 0.65);
  cursor: pointer;
  font-size: 0.78rem;
  letter-spacing: 0.2em;
  font-family: var(--hl-font);
  transition: color 0.2s;
  animation: curtain-fade-up 0.9s ease 0.8s both;
}

.curtain-scroll-btn:hover {
  color: #fff;
}

.curtain-scroll-arrow {
  animation: curtain-arrow-bounce 1.8s ease-in-out infinite;
}


/* ---- Keyframes ---- */
@keyframes curtain-zoom {
  from {
    transform: scale(1);
  }
  to {
    transform: scale(1.06);
  }
}

@keyframes curtain-fade-up {
  from {
    opacity: 0;
    transform: translateY(24px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes curtain-cursor-blink {
  0%, 100% {
    opacity: 1;
  }
  50% {
    opacity: 0;
  }
}

@keyframes curtain-arrow-bounce {
  0%, 100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(10px);
  }
}

/* --- Hide header while curtain fills viewport --- */
header.header--curtain-hidden {
  opacity: 0;
  pointer-events: none;
  transform: translateY(-6px);
}

/* --- Account for fixed header when articles follow curtain --- */
.hl-curtain ~ main {
  padding-top: var(--hl-header-height);
}