/* Reset & Base */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    sans-serif;
  background: linear-gradient(145deg, var(--bg-primary), var(--bg-secondary));
  color: var(--text);
  min-height: 100vh;
  transition: background 0.5s ease, color 0.5s ease;
  line-height: 1.6;
}

/* Google Inter Font */
@import url("https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&display=swap");

.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 2.5rem 1.5rem;
}

/* Themes */
:root {
  --accent: #7c3aed; /* Vibrant purple */
  --accent-light: #a78bfa; /* Softer purple */
  --bg-primary: #f4f7fe;
  --bg-secondary: #e0e7ff;
  --card-bg: rgba(255, 255, 255, 0.95);
  --text: #1f2937;
  --border: rgba(209, 213, 219, 0.5);
  --shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
  --legend-bg: rgba(243, 244, 246, 0.9);
  --error: #ef4444;
  --grid: rgba(139, 92, 246, 0.15);
}

.dark-theme {
  --accent: #a78bfa;
  --accent-light: #60a5fa; /* Bright blue for contrast */
  --bg-primary: #1e1e3f;
  --bg-secondary: #2d2d5a;
  --card-bg: rgba(30, 30, 58, 0.95);
  --text: #e5e7eb;
  --border: rgba(107, 114, 128, 0.4);
  --shadow: 0 10px 40px rgba(0, 0, 0, 0.4);
  --legend-bg: rgba(55, 65, 81, 0.9);
  --error: #f87171;
  --grid: rgba(139, 92, 246, 0.2);
}

/* Header */
.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2.5rem;
  flex-wrap: wrap;
  gap: 1.5rem;
}

.header h1 {
  font-size: 2.5rem;
  font-weight: 800;
  background: linear-gradient(90deg, var(--accent), var(--accent-light));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  letter-spacing: -0.8px;
  text-transform: uppercase;
}

.btn-toggle {
  padding: 0.7rem 1.5rem;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 50px;
  cursor: pointer;
  font-weight: 600;
  font-size: 1rem;
  box-shadow: var(--shadow);
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  gap: 0.6rem;
  position: relative;
  overflow: hidden;
}

.btn-toggle::after {
  content: "";
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    90deg,
    transparent,
    rgba(255, 255, 255, 0.2),
    transparent
  );
  transition: 0.5s;
}

.btn-toggle:hover::after {
  left: 100%;
}

.btn-toggle:hover {
  transform: translateY(-3px);
  box-shadow: 0 12px 30px rgba(108, 92, 231, 0.4);
  background: var(--accent-light);
}

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

/* Card */
.card {
  background: var(--card-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-radius: 20px;
  box-shadow: var(--shadow);
  padding: 2rem;
  margin-bottom: 2rem;
  border: 1px solid var(--border);
  transition: transform 0.4s ease, box-shadow 0.4s ease;
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: 0 12px 50px rgba(0, 0, 0, 0.15);
}

.card h2,
.card h3 {
  color: var(--accent);
  margin-bottom: 1.5rem;
  font-weight: 700;
  font-size: 1.5rem;
}

/* Input Section */
.input-section label {
  display: block;
  margin-bottom: 1rem;
  font-weight: 600;
  font-size: 1.1rem;
  color: var(--text);
}

#binary-input {
  width: 100%;
  padding: 1rem 1.3rem;
  font-size: 1.15rem;
  border: 2px solid var(--border);
  border-radius: 14px;
  background: var(--card-bg);
  color: var(--text);
  outline: none;
  transition: all 0.3s ease;
}

#binary-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 4px rgba(108, 92, 231, 0.25);
  background: rgba(255, 255, 255, 0.98);
}

.dark-theme #binary-input:focus {
  background: rgba(30, 30, 58, 0.98);
}

.error {
  color: var(--error);
  font-size: 0.95rem;
  margin-top: 0.8rem;
  font-weight: 500;
  opacity: 0;
  height: 1.2em;
  transition: opacity 0.4s ease;
}

.error.show {
  opacity: 1;
}

/* Encoding Buttons */
.encoding-buttons {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 1rem;
  justify-content: center;
  padding: 1rem 0;
}

.encoding-buttons button {
  padding: 0.8rem 1.6rem;
  font-size: 1.05rem;
  background: var(--card-bg);
  color: var(--text);
  border: 2px solid var(--border);
  border-radius: 14px;
  cursor: pointer;
  font-weight: 600;
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
  text-transform: capitalize;
}

.encoding-buttons button::before {
  content: "";
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--accent-light));
  opacity: 0;
  z-index: -1;
  transition: all 0.4s ease;
  border-radius: 14px;
}

.encoding-buttons button:hover {
  color: #fff;
  border-color: var(--accent);
  transform: translateY(-3px);
  box-shadow: 0 8px 25px rgba(108, 92, 231, 0.3);
}

.encoding-buttons button:hover::before {
  opacity: 1;
  left: 0;
}

.encoding-buttons button.active {
  color: #fff;
  border-color: var(--accent);
  background: linear-gradient(90deg, var(--accent), var(--accent-light));
  box-shadow: 0 10px 30px rgba(108, 92, 231, 0.4);
  font-weight: 700;
  transform: translateY(-2px);
}

/* Legend */
.legend-section {
  background: var(--legend-bg);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-radius: 16px;
  padding: 1.6rem;
  font-size: 1.05rem;
  line-height: 1.8;
  border: 1px solid var(--border);
  transition: all 0.3s ease;
}

.legend-section h3 {
  font-size: 1.3rem;
  font-weight: 600;
}

/* Chart */
.chart-section {
  position: relative;
  padding: 2rem;
  background: var(--card-bg);
  border-radius: 20px;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  transition: all 0.3s ease;
}

#signal-canvas {
  width: 100% !important;
  height: 350px !important;
  border-radius: 14px;
  background: rgba(0, 0, 0, 0.03);
  display: block;
  margin-top: 1rem;
}

.dark-theme #signal-canvas {
  background: rgba(255, 255, 255, 0.05);
}

/* Pulse Animation */
@keyframes pulse {
  0% {
    opacity: 0.5;
    transform: scale(0.98);
  }
  50% {
    opacity: 1;
    transform: scale(1);
  }
  100% {
    opacity: 0.5;
    transform: scale(0.98);
  }
}

.pulse {
  animation: pulse 0.8s ease-in-out;
}

/* Responsive */
@media (max-width: 768px) {
  .header {
    flex-direction: column;
    text-align: center;
    gap: 1.2rem;
  }

  .header h1 {
    font-size: 2rem;
  }

  .btn-toggle {
    align-self: center;
    padding: 0.6rem 1.2rem;
  }

  .card {
    padding: 1.5rem;
  }

  .encoding-buttons {
    grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
  }
}

@media (max-width: 480px) {
  .container {
    padding: 1.2rem;
  }

  .header h1 {
    font-size: 1.7rem;
  }

  .encoding-buttons button {
    font-size: 0.95rem;
    padding: 0.7rem 1.2rem;
  }

  .card {
    padding: 1.2rem;
  }

  .chart-section {
    padding: 1.5rem;
  }

  #signal-canvas {
    height: 250px !important;
  }
}