:root {
  --green: #96e150;
  --purple: #7864fa;
  --blue: #1e96ff;
  --white: #ffffff;
  --black: #000000;

  /* Enhanced dark background & glow */
  --bg-linear-start: #0a0a0a; /* near-black */
  --bg-linear-end: #141827; /* deep navy */
  --glow-1: rgba(120, 100, 250, 0.35); /* increased */
  --glow-2: rgba(30, 150, 255, 0.3); /* increased */
  --glow-3: rgba(150, 225, 80, 0.22); /* green glow */
  --text-color: var(--white);
  --card-bg: rgba(255, 255, 255, 0.08);
  --card-border: rgba(255, 255, 255, 0.15);
  --button-primary-start: var(--purple);
  --button-primary-end: var(--blue);
  --button-primary-shadow: rgba(120, 100, 250, 0.4);
  --button-secondary-start: var(--green);
  --button-secondary-end: #7ac640;
  --button-secondary-shadow: rgba(150, 225, 80, 0.4);
  --info-text-color: var(--green);
  --highlight-text-color: var(--purple);
}

[data-theme="light"] {
  --bg-linear-start: #f4f6ff; /* soft white-blue */
  --bg-linear-end: #e9fdea; /* soft green tint */
  --glow-1: rgba(120, 100, 250, 0.18);
  --glow-2: rgba(30, 150, 255, 0.18);
  --glow-3: rgba(150, 225, 80, 0.15);
  --card-bg: rgba(255, 255, 255, 0.7);
  --card-border: rgba(0, 0, 0, 0.08);
  --text-color: var(--black);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: "Barlow", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    sans-serif;
  background: radial-gradient(
      circle at 20% 30%,
      var(--glow-1) 0%,
      transparent 45%
    ),
    radial-gradient(circle at 80% 70%, var(--glow-2) 0%, transparent 55%),
    radial-gradient(circle at 50% 50%, var(--glow-3) 0%, transparent 70%),
    linear-gradient(
      135deg,
      var(--bg-linear-start) 0%,
      var(--bg-linear-end) 100%
    );
  color: var(--text-color);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

#app {
  width: 100%;
  max-width: 1200px;
  margin: 20px;
  display: grid;
  grid-template-areas:
    "header header"
    "controls cube"
    "status cube"
    "footer footer";
  grid-template-columns: 350px 1fr;
  grid-template-rows: auto auto 1fr auto;
  gap: 20px;
  height: calc(100vh - 40px);
}

header {
  grid-area: header;
  text-align: center;
  padding: 20px;
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  border-radius: 15px;
  border: 1px solid rgba(255, 255, 255, 0.2);
}

h1 {
  font-size: 2.5rem;
  font-weight: 800;
  background: linear-gradient(45deg, var(--green), var(--purple), var(--blue));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 10px;
}

.subtitle {
  font-size: 1.1rem;
  opacity: 0.8;
  font-weight: 300;
}

#controls {
  grid-area: controls;
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  border-radius: 15px;
  border: 1px solid rgba(255, 255, 255, 0.2);
  padding: 25px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.control-group:first-child {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 15px;
}

.btn {
  padding: 12px 20px;
  border: none;
  border-radius: 8px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  font-size: 14px;
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.2);
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
}

.btn:active {
  transform: translateY(0);
}

.btn.primary {
  background: linear-gradient(
    45deg,
    var(--button-primary-start),
    var(--button-primary-end)
  );
  color: var(--white);
  box-shadow: 0 4px 15px var(--button-primary-shadow);
}

.btn.primary:hover {
  box-shadow: 0 8px 25px var(--button-primary-shadow);
}

.btn.secondary {
  background: linear-gradient(
    45deg,
    var(--button-secondary-start),
    var(--button-secondary-end)
  );
  color: var(--white);
  box-shadow: 0 4px 15px var(--button-secondary-shadow);
}

.btn.secondary:hover {
  box-shadow: 0 8px 25px var(--button-secondary-shadow);
}

.btn.tertiary {
  background: rgba(255, 255, 255, 0.2);
  color: white;
  box-shadow: 0 4px 15px rgba(255, 255, 255, 0.1);
}

.btn.tertiary:hover {
  background: rgba(255, 255, 255, 0.3);
  box-shadow: 0 8px 25px rgba(255, 255, 255, 0.2);
}

.info {
  background: rgba(255, 255, 255, 0.1);
  padding: 15px;
  border-radius: 10px;
  border: 1px solid rgba(255, 255, 255, 0.2);
}

.info p {
  margin-bottom: 10px;
  color: var(--info-text-color);
}

.info ul {
  list-style: none;
  padding-left: 0;
}

.info li {
  padding: 5px 0;
  font-size: 14px;
  opacity: 0.9;
}

#cube-container {
  grid-area: cube;
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  border-radius: 15px;
  border: 1px solid rgba(255, 255, 255, 0.2);
  padding: 20px;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 500px;
}

twisty-player {
  width: 100%;
  height: 100%;
  min-height: 500px;
}

#status {
  grid-area: status;
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  border-radius: 15px;
  border: 1px solid rgba(255, 255, 255, 0.2);
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

#status p {
  font-size: 14px;
  padding: 8px 12px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 8px;
  border: 1px solid rgba(255, 255, 255, 0.2);
}

#moveCounter {
  color: var(--info-text-color);
  font-weight: 600;
}

#currentAlg {
  color: var(--highlight-text-color);
  font-weight: 600;
  word-break: break-all;
}

/* Responsive Design */
@media (max-width: 1024px) {
  #app {
    grid-template-areas:
      "header"
      "cube"
      "controls"
      "status"
      "footer";
    grid-template-columns: 1fr;
    grid-template-rows: auto 400px auto auto auto;
  }

  .control-group:first-child {
    grid-template-columns: 1fr;
  }

  h1 {
    font-size: 2rem;
  }
}

@media (max-width: 768px) {
  body {
    padding: 10px;
  }

  #app {
    margin: 10px;
    gap: 15px;
    height: auto;
  }

  header {
    padding: 15px;
  }

  h1 {
    font-size: 1.8rem;
  }

  .subtitle {
    font-size: 1rem;
  }

  #controls {
    padding: 20px;
  }

  #cube-container {
    min-height: 350px;
    padding: 15px;
  }

  twisty-player {
    min-height: 350px;
  }
}

/* Loading animation */
.loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100%;
  color: var(--info-text-color);
}

.spinner {
  width: 40px;
  height: 40px;
  border: 3px solid rgba(30, 150, 255, 0.3);
  border-top: 3px solid var(--blue);
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin-bottom: 15px;
}

@keyframes spin {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

/* Themed card backgrounds */
header,
footer,
#controls,
.info,
#cube-container,
#status,
#status p {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
}

.btn.tertiary {
  background: var(--card-bg);
  color: var(--text-color);
  box-shadow: 0 4px 15px var(--card-border);
}

.btn.tertiary:hover {
  background: rgba(255, 255, 255, 0.3);
  box-shadow: 0 8px 25px var(--card-border);
}

/* Footer */
footer {
  grid-area: footer;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 15px;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 15px;
  backdrop-filter: blur(10px);
}

/* Theme toggle button */
.theme-toggle {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  font-size: 1.4rem;
  display: flex;
  justify-content: center;
  align-items: center;
  background: transparent;
  border: none;
  cursor: pointer;
  transition: transform 0.3s ease;
}
.theme-toggle:hover {
  transform: scale(1.1);
}