:root {
    --bg: #1a1a2e;
    --surface: #16213e;
    --surface2: #0f3460;
    --accent: #e94560;
    --accent2: #4ecca3;
    --text: #eee;
    --text-dim: #999;
    --border: #2a2a4a;
    --success: #4ecca3;
    --error: #e94560;
    --warning: #f6c244;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
}

/* Layout */
.container { max-width: 1200px; margin: 0 auto; padding: 1rem; }

header {
    background: var(--surface);
    border-bottom: 2px solid var(--border);
    padding: 0.75rem 1rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
}
header h1 { font-size: 1.3rem; color: var(--accent2); }
header .user-info { font-size: 0.85rem; color: var(--text-dim); }
header .role-badge {
    display: inline-block; padding: 2px 8px; border-radius: 4px;
    background: var(--surface2); color: var(--accent2); font-size: 0.75rem;
    margin-left: 0.5rem;
}

/* Cards */
.card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1.5rem;
    margin: 1rem 0;
}

/* Buttons */
.btn {
    display: inline-block; padding: 0.5rem 1.2rem;
    border: none; border-radius: 6px; cursor: pointer;
    font-size: 0.9rem; font-weight: 500;
    transition: all 0.2s;
}
.btn-primary { background: var(--accent2); color: var(--bg); }
.btn-primary:hover { opacity: 0.85; }
.btn-secondary { background: var(--surface2); color: var(--text); }
.btn-secondary:hover { background: var(--border); }
.btn-danger { background: var(--accent); color: white; }
.btn-sm { padding: 0.3rem 0.7rem; font-size: 0.8rem; }
.btn:disabled { opacity: 0.4; cursor: not-allowed; }

/* Forms */
.form-group { margin-bottom: 1rem; }
.form-group label { display: block; margin-bottom: 0.3rem; font-size: 0.85rem; color: var(--text-dim); }
.form-group input, .form-group select, .form-group textarea {
    width: 100%; padding: 0.5rem; border-radius: 6px;
    border: 1px solid var(--border); background: var(--bg);
    color: var(--text); font-size: 0.9rem;
}
.form-group textarea { min-height: 100px; font-family: 'Courier New', monospace; }
.form-row { display: flex; gap: 1rem; }
.form-row > * { flex: 1; }

/* Toggle switches */
.toggle { display: flex; align-items: center; gap: 0.5rem; }
.toggle input[type="checkbox"] { width: 18px; height: 18px; accent-color: var(--accent2); }

/* Tables */
table { width: 100%; border-collapse: collapse; margin: 0.5rem 0; }
th, td { padding: 0.5rem; text-align: left; border-bottom: 1px solid var(--border); }
th { color: var(--text-dim); font-weight: 500; font-size: 0.85rem; }

/* Simulator areas */
.sim-container { margin-top: 1rem; }
.sim-toolbar { display: flex; gap: 0.5rem; align-items: center; flex-wrap: wrap; margin-bottom: 0.5rem; }

/* Turing machine tape */
.tape-container {
    overflow-x: auto; padding: 1rem 0;
    border: 1px solid var(--border); border-radius: 8px;
    background: var(--bg); margin: 0.5rem 0;
}
.tape { display: flex; min-height: 48px; }
.tape-cell {
    min-width: 40px; height: 48px;
    display: flex; align-items: center; justify-content: center;
    border: 1px solid var(--border); font-family: monospace;
    font-size: 1.1rem; position: relative;
    transition: all 0.2s;
}
.tape-cell.head {
    border-color: var(--accent2); border-width: 2px;
    box-shadow: 0 0 8px rgba(78,204,163,0.3);
}
.tape-cell.head::after {
    content: "▼"; position: absolute; top: -16px; left: 50%;
    transform: translateX(-50%); color: var(--accent2); font-size: 0.8rem;
}
.tape-cell.active { background: var(--surface2); }
.state-display {
    display: inline-block; padding: 4px 12px;
    background: var(--surface2); border-radius: 4px;
    font-family: monospace; font-size: 0.9rem; margin: 0.5rem 0;
}
.state-display .label { color: var(--text-dim); }
.state-display .value { color: var(--accent2); margin-left: 0.5rem; }

/* Transition table editor */
.transition-editor { overflow-x: auto; }
.transition-editor table { min-width: 100%; }
.transition-editor th, .transition-editor td {
    text-align: center; min-width: 80px;
}
.transition-editor input, .transition-editor select {
    width: 100%; max-width: 80px; padding: 4px;
    border: 1px solid var(--border); background: var(--bg);
    color: var(--text); border-radius: 4px; font-size: 0.85rem;
    font-family: monospace;
}

/* Markov rules editor */
.markov-rules { list-style: none; padding: 0; }
.markov-rule {
    display: flex; align-items: center; gap: 0.5rem; margin-bottom: 0.4rem;
}
.markov-rule input { padding: 4px 8px; border: 1px solid var(--border);
    background: var(--bg); color: var(--text); border-radius: 4px;
    font-family: monospace; font-size: 0.9rem; }
.markov-rule .arrow { color: var(--accent2); font-size: 1.1rem; }
.markov-rule .terminal { font-size: 0.8rem; color: var(--text-dim); }
.markov-rule .btn-remove { padding: 2px 8px; font-size: 0.75rem; }

/* Boolean editor */
.boolean-editor textarea {
    width: 100%; min-height: 60px; padding: 0.75rem;
    border: 2px solid var(--border); border-radius: 8px;
    background: var(--bg); color: var(--text);
    font-family: 'Courier New', monospace; font-size: 1.1rem;
    resize: vertical;
}
.boolean-editor textarea:focus { border-color: var(--accent2); outline: none; }
.boolean-symbols { font-size: 0.8rem; color: var(--text-dim); margin-top: 0.3rem; }
.truth-table { margin-top: 0.5rem; }
.truth-table th, .truth-table td { text-align: center; padding: 4px 8px; }
.truth-table .true { color: var(--success); }
.truth-table .false { color: var(--error); }

/* Test results */
.test-results { margin-top: 1rem; }
.test-result {
    display: flex; align-items: center; gap: 0.5rem;
    padding: 0.5rem; border-radius: 4px; margin-bottom: 0.3rem;
    font-family: monospace; font-size: 0.85rem;
}
.test-result.pass { background: rgba(78,204,163,0.1); }
.test-result.fail { background: rgba(233,69,96,0.1); }
.test-result .icon { font-size: 1.1rem; }
.test-result.pass .icon { color: var(--success); }
.test-result.fail .icon { color: var(--error); }

/* Step controls */
.step-controls {
    display: flex; gap: 0.5rem; align-items: center; margin: 0.5rem 0;
}
.step-info { font-size: 0.85rem; color: var(--text-dim); margin-left: 0.5rem; }

/* Assignment list */
.assignment-list { list-style: none; padding: 0; }
.assignment-item {
    display: flex; justify-content: space-between; align-items: center;
    padding: 0.75rem; border: 1px solid var(--border); border-radius: 6px;
    margin-bottom: 0.5rem; background: var(--bg);
}
.assignment-item:hover { border-color: var(--accent2); }
.type-badge {
    display: inline-block; padding: 2px 8px; border-radius: 4px;
    font-size: 0.75rem; font-weight: 500; margin-right: 0.5rem;
}
.type-badge.turing { background: rgba(233,69,96,0.2); color: var(--accent); }
.type-badge.markov { background: rgba(246,194,68,0.2); color: var(--warning); }
.type-badge.boolean { background: rgba(78,204,163,0.2); color: var(--success); }

/* Misc */
.hidden { display: none; }
.loading { text-align: center; padding: 2rem; color: var(--text-dim); }
.error-text { color: var(--error); }
.success-text { color: var(--success); }
.hint { font-size: 0.85rem; color: var(--text-dim); margin-top: 0.5rem; }
.empty-state { text-align: center; padding: 2rem; color: var(--text-dim); }

/* Markov simulator (sim_markov.js) */
.markov-sim .markov-input {
    flex: 1; min-width: 200px; padding: 6px 10px;
    border: 1px solid var(--border); background: var(--bg);
    color: var(--text); border-radius: 6px;
    font-family: 'Courier New', monospace; font-size: 0.95rem;
}
.markov-string-view {
    padding: 0.75rem; border: 1px solid var(--border); border-radius: 6px;
    background: var(--bg); min-height: 48px; overflow-x: auto;
}
.markov-string {
    font-family: 'Courier New', monospace; font-size: 1.1rem;
    letter-spacing: 1px; word-break: break-all; white-space: pre-wrap;
}
.markov-string .m-match {
    background: var(--warning); color: var(--bg);
    border-radius: 3px; padding: 1px 3px; font-weight: 600;
}
.markov-string .m-before, .markov-string .m-after { color: var(--text); }
.markov-string .m-badge {
    margin-left: 0.5rem; font-size: 0.8rem; padding: 2px 8px;
    border-radius: 4px; font-weight: 600;
}
.markov-string .m-badge-terminal { background: rgba(246,194,68,0.25); color: var(--warning); }
.markov-string .m-badge-done { background: rgba(78,204,163,0.2); color: var(--accent2); }
.markov-trace {
    max-height: 220px; overflow-y: auto; padding: 0.5rem;
    border: 1px solid var(--border); border-radius: 6px;
    background: var(--bg); font-family: 'Courier New', monospace;
    font-size: 0.82rem; color: var(--text-dim);
}
.markov-trace-line { padding: 2px 0; border-bottom: 1px solid rgba(42,42,74,0.5); }
.markov-trace-line:last-child { border-bottom: none; }
.markov-final {
    padding: 0.6rem 0.75rem; border: 1px solid var(--accent2);
    border-radius: 6px; background: var(--bg);
    font-family: 'Courier New', monospace; font-size: 1.05rem;
    color: var(--accent2); word-break: break-all;
}
.markov-rule .btn-sm { padding: 2px 6px; font-size: 0.75rem; min-width: 28px; }
.markov-sim .toggle.terminal { font-size: 0.8rem; color: var(--text-dim); white-space: nowrap; }