/* RESET và nền video */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
html, body {
  height: 100%;
  overflow: hidden;
  font-family: Arial, sans-serif;
}

#background-video {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  object-fit: cover;
  z-index: -1;
  filter: brightness(0.5);
}

/* Overlay mở đầu */
#start-overlay {
  position: fixed;
  z-index: 20;
  inset: 0;
  background: rgba(0,0,0,0.8);
  display: flex;
  justify-content: center;
  align-items: center;
}

#start-button {
  font-size: 1.3rem;
  padding: 15px 25px;
  background-color: #8e44ad;
  color: white;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  transition: 0.3s;
}

#start-button:hover {
  background-color: #9b59b6;
}

/* Nút toggle nhạc */
#music-toggle {
  position: fixed;
  top: 10px;
  right: 10px;
  padding: 10px;
  background: #fff;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  font-size: 18px;
  z-index: 10;
}

/* Container chính */
.profile-container {
  text-align: center;
  color: white;
  padding: 60px 20px;
  font-family: 'Segoe UI', sans-serif;
  text-shadow: 0 0 5px #b67ee6;
  position: relative;
}

/* Nút xem thêm */
.button {
  background-color: #b67ee6;
  border: none;
  padding: 10px 20px;
  margin: 10px;
  color: white;
  border-radius: 10px;
  cursor: pointer;
  position: relative;
  overflow: hidden;
  transition: background 0.3s;
}

.button:hover {
  background-color: #a34bdc;
}

/* Ripple effect */
.button::after {
  content: '';
  position: absolute;
  background: rgba(255,255,255,0.6);
  border-radius: 50%;
  width: 100px;
  height: 100px;
  transform: scale(0);
  opacity: 0;
  transition: 0.6s;
  pointer-events: none;
}

.button:active::after {
  transform: scale(2);
  opacity: 1;
  transition: 0s;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%) scale(1);
}

/* Menu hình tròn cảm ứng trong suốt giữa màn */
.menu-circle {
  position: absolute;
  top: calc(100% + 20px);
  left: 50%;
  transform: translateX(-50%);
  z-index: 5;
}

.menu-toggle {
  background-color: rgba(255,255,255,0.1);
  border: 2px solid rgba(255,255,255,0.3);
  color: white;
  width: 70px;
  height: 70px;
  border-radius: 50%;
  font-size: 26px;
  cursor: pointer;
  backdrop-filter: blur(10px);
  transition: 0.3s;
}

.menu-toggle:hover {
  background-color: rgba(255,255,255,0.2);
}

.circle-options {
  position: absolute;
  top: 0;
  left: 50%;
  transform: translate(-50%, -120%);
  display: none;
  flex-direction: row;
  gap: 20px;
  align-items: center;
}

.circle-options a {
  background-color: rgba(255,255,255,0.1);
  color: #fff;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  display: flex;
  justify-content: center;
  align-items: center;
  text-decoration: none;
  font-size: 18px;
  backdrop-filter: blur(5px);
  transition: background 0.3s, transform 0.3s;
}

.circle-options a:hover {
  background-color: rgba(255,255,255,0.3);
  transform: scale(1.1);
}

.menu-circle:hover .circle-options {
  display: flex;
}

/* Hiệu ứng chớp tắt */
.flicker {
  animation: flickerAnimation 2s infinite;
}

@keyframes flickerAnimation {
  0%, 19%, 21%, 23%, 25%, 54%, 56%, 100% {
    opacity: 1;
    text-shadow: 0 0 8px #fff, 0 0 12px #b64fd4;
  }
  20%, 24%, 55% {
    opacity: 0.4;
    text-shadow: none;
  }
}

/* Avatar nhỏ tròn */
.avatar {
  width: 100px;
  height: 100px;
  object-fit: cover;
  border-radius: 50%;
  border: 3px solid white;
  margin-bottom: 10px;
}