/* =========================================
   2. 자연과 빛의 파동 컨셉
   ========================================= */
body { 
  background: linear-gradient(135deg, #0f2027, #203a43, #2c5364); 
  background-size: 400% 400%;
  animation: gradientBG 15s ease infinite;
  color: white; font-family: 'Cinzel', serif; 
}
@keyframes gradientBG { 0% {background-position: 0% 50%;} 50% {background-position: 100% 50%;} 100% {background-position: 0% 50%;} }

.nature-time-wrapper { 
  text-align: center; 
  transform: translateY(-40px);
  display: flex;
  flex-direction: column;
  align-items: center;
  transition: 0.3s;
}
.nature-time { 
  font-size: 11rem; font-weight: 400; letter-spacing: 15px; 
  text-shadow: 0 0 40px rgba(255,255,255,0.4); 
  transition: filter 0.8s ease, transform 0.8s ease, opacity 0.8s ease, font-size 0.3s; 
}
.nature-time.wave-effect { filter: blur(15px); transform: scale(1.05); opacity: 0.6; }

.nature-sub { margin-top: 10px; transition: 0.3s; }

.nature-select {
  background: rgba(0, 0, 0, 0.2);
  border: 1px solid rgba(255, 255, 255, 0.2);
  color: white;
  font-family: 'Cinzel', serif;
  font-size: 14px;
  letter-spacing: 4px;
  padding: 8px 15px;
  border-radius: 8px;
  outline: none;
  cursor: pointer;
  text-align: center;
  transition: 0.3s;
}
.nature-select:hover { border: 1px solid rgba(255, 255, 255, 0.6); }
.nature-select option { background: #11222c; color: white; }

/* 리얼 모래시계 디자인 */
.hourglass-container {
  margin-top: 50px; 
  transition: transform 0.3s;
}
.hourglass {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
}
.hourglass.flip {
  animation: flipAnim 1s cubic-bezier(0.65, 0, 0.35, 1) forwards;
}
@keyframes flipAnim {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(180deg); }
}

.glass-top, .glass-bottom {
  width: 110px; 
  height: 120px;
  background: rgba(255, 255, 255, 0.03);
  position: relative;
  overflow: hidden;
  box-shadow: inset 0 0 20px rgba(255,255,255,0.08);
  backdrop-filter: blur(2px);
}
.glass-top {
  border-radius: 10px 10px 45px 45px / 10px 10px 100px 100px;
  border: 2px solid rgba(255, 255, 255, 0.2);
  border-bottom: none;
}
.glass-bottom {
  border-radius: 45px 45px 10px 10px / 100px 100px 10px 10px;
  border: 2px solid rgba(255, 255, 255, 0.2);
  border-top: none;
}

.neck-band {
  width: 26px;
  height: 6px;
  background: rgba(255, 255, 255, 0.4);
  border-radius: 3px;
  z-index: 10;
  margin-top: -3px;
  margin-bottom: -3px;
  box-shadow: 0 0 10px rgba(0, 255, 204, 0.4);
}

.liquid-top, .liquid-bottom {
  position: absolute;
  left: 0;
  width: 100%;
  background: rgba(0, 255, 204, 0.6);
  box-shadow: 0 0 20px rgba(0, 255, 204, 0.4);
  border-top: 2px solid rgba(0, 255, 204, 0.9); 
}
.liquid-top { bottom: 0; height: 100%; }
.liquid-bottom { bottom: 0; height: 0%; }

.drop-particle {
  position: absolute;
  top: 120px; 
  left: 50%;
  transform: translateX(-50%);
  width: 4px;
  height: 12px;
  background: rgba(0, 255, 204, 0.9);
  border-radius: 50%;
  box-shadow: 0 0 10px rgba(0, 255, 204, 0.8);
  animation: dropAnim 0.7s cubic-bezier(0.4, 0, 1, 1) infinite;
  z-index: 5;
}
@keyframes dropAnim {
  0% { top: 120px; opacity: 1; transform: translateX(-50%) scale(0.8); }
  80% { top: 220px; opacity: 1; transform: translateX(-50%) scale(1.1); }
  100% { top: 230px; opacity: 0; transform: translateX(-50%) scale(0); }
}

@media (max-width: 768px) {
  .nature-time-wrapper {
    transform: translateY(-20px) scale(0.7);
  }
  .nature-time {
    font-size: 8rem;
    letter-spacing: 5px;
  }
}