:root {
  --bg-color: #121826;
  --card-color: #1a2233;
  --text-color: #e5e7eb;
  --muted-color: #94a3b8;
  --primary-color: #22d3ee;
  --border-color: #334155;
  --input-bg: #2a3447;
  --color-dont-care: #777;
  --color-one: #4ade80;
  --color-zero: #718096;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen,
    Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  margin: 0;
  padding: 20px;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.container {
  width: 100%;
  max-width: 900px;
}

header {
  text-align: center;
  margin-bottom: 2rem;
}

header h1 {
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
  color: var(--primary-color);
}

footer {
  text-align: center;
  margin-top: 40px;
  padding: 20px 0;
  border-top: 1px solid var(--border-color);
  color: var(--muted-color);
}
footer a {
  color: var(--primary-color);
  text-decoration: none;
}
footer a:hover {
  text-decoration: underline;
}

.controls {
  background-color: var(--card-color);
  padding: 1.5rem;
  border-radius: 12px;
  border: 1px solid var(--border-color);
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
  align-items: end;
  margin-bottom: 2rem;
}

.input-group {
  display: flex;
  flex-direction: column;
}

.input-group label {
  font-size: 0.9rem;
  margin-bottom: 0.25rem;
  color: var(--muted-color);
}

.input-group input[type="text"],
.input-group select {
  background-color: var(--input-bg);
  border: 1px solid var(--border-color);
  color: var(--text-color);
  padding: 0.75rem;
  border-radius: 8px;
  font-size: 1rem;
  width: 100%;
  box-sizing: border-box; /* Ensures padding doesn't affect width */
}

.input-group.checkbox-group {
  flex-direction: row;
  align-items: center;
  gap: 0.5rem;
  align-self: center;
}

#solve-btn {
  background-color: var(--primary-color);
  color: var(--bg-color);
  border: none;
  padding: 0.75rem 1.5rem;
  font-size: 1rem;
  font-weight: bold;
  border-radius: 8px;
  cursor: pointer;
  transition: background-color 0.2s;
  width: 100%;
}

#solve-btn:hover {
  background-color: #67e8f9;
}

#solution {
  margin-top: 2rem;
}

.solution-step {
  background-color: var(--card-color);
  padding: 1.5rem;
  border-radius: 12px;
  border: 1px solid var(--border-color);
  margin-bottom: 1.5rem;
  overflow-x: auto; /* Allow horizontal scroll for tables */
}
.solution-step.group-step {
  background-color: #161d2d; /* Slightly different bg for group details */
}

.solution-step h2 {
  margin-top: 0;
  font-size: 1.5rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 0.5rem;
  margin-bottom: 1rem;
}

.final-expression {
  font-family: "Courier New", Courier, monospace;
  font-size: 1.2rem;
  font-weight: bold;
  color: var(--primary-color);
  background-color: var(--input-bg);
  padding: 1rem;
  border-radius: 8px;
  border: 2px solid var(--primary-color);
  white-space: pre-wrap;
  word-wrap: break-word;
}

.kmap-container {
  display: flex;
  gap: 2rem;
  justify-content: center;
  align-items: flex-start;
  overflow-x: auto;
  padding-bottom: 10px;
}

.kmap-table {
  border-collapse: collapse;
  font-family: "Courier New", Courier, monospace;
}

.kmap-table th,
.kmap-table td {
  border: 1px solid var(--border-color);
  width: 50px;
  height: 50px;
  text-align: center;
  position: relative;
  vertical-align: middle;
}

.kmap-table th {
  background-color: var(--input-bg);
  font-weight: normal;
}

.kmap-table td {
  font-size: 1.2rem;
  font-weight: bold;
}
.kmap-table td span.dont-care {
  color: var(--color-dont-care);
  font-weight: normal;
}
.kmap-table td span:not(.minterm-index) {
  font-size: 1.25rem;
  font-weight: bold;
}

.kmap-table .minterm-index {
  position: absolute;
  top: 2px;
  left: 2px;
  font-size: 0.6rem;
  color: var(--muted-color);
  font-weight: normal;
}

#error-message {
  color: #f87171;
  text-align: center;
  margin: -1rem 0 1rem 0;
  font-weight: bold;
  min-height: 1.2em;
}

/* --- New Styles for Added Steps --- */

/* Truth Table */
.truth-table {
  border-collapse: collapse;
  width: 100%;
  min-width: 400px;
  font-family: "Courier New", Courier, monospace;
}
.truth-table th,
.truth-table td {
  border: 1px solid var(--border-color);
  padding: 8px 12px;
  text-align: center;
}
.truth-table th {
  background-color: var(--input-bg);
}
.truth-table tr:nth-child(even) {
  background-color: rgba(255, 255, 255, 0.02);
}
.truth-table td.out-one {
  color: var(--color-one);
  font-weight: bold;
}
.truth-table td.out-zero {
  color: var(--color-zero);
}
.truth-table td.dont-care {
  color: var(--color-dont-care);
}
.truth-table td.minterm-index {
  color: var(--muted-color);
  font-size: 0.8em;
  border-right: 2px solid var(--border-color);
}

/* Standard Forms */
.std-form {
  font-family: "Courier New", Courier, monospace;
  font-size: 1.1rem;
  padding: 8px;
  background: var(--input-bg);
  border-radius: 6px;
  margin-bottom: 10px;
  color: var(--text-color);
}
.std-form strong {
  color: var(--primary-color);
}

/* Circuit Logic */
.circuit-logic {
  line-height: 1.6;
}
.circuit-logic h4 {
  color: var(--primary-color);
  margin-top: 1rem;
  margin-bottom: 0.5rem;
  border-bottom: 1px dashed var(--border-color);
  padding-bottom: 4px;
}
.circuit-logic ol {
  margin: 0;
  padding-left: 20px;
}
.circuit-logic li {
  margin-bottom: 8px;
}