/* ═══════════════════════════════════════════
   ATONAL FUGUE — CRT TERMINAL AESTHETIC
   BLACK & WHITE PHOSPHOR DISPLAY
   ═══════════════════════════════════════════ */

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

:root {
  --bg: #0a0a0a;
  --fg: #c8c8c8;
  --fg-bright: #e0e0e0;
  --fg-dim: #666666;
  --fg-accent: #ffffff;
  --glow: rgba(200, 200, 200, 0.3);
  --glow-strong: rgba(255, 255, 255, 0.15);
  --font: 'VT323', monospace;
}

html {
  font-size: 18px;
  scroll-behavior: smooth;
}

body {
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font);
  line-height: 1.5;
  text-shadow: 0 0 4px var(--glow);
  overflow-x: hidden;
  min-height: 100vh;
  position: relative;
}

/* ─── CRT EFFECTS ─── */

/* Scanlines */
.crt::before {
  content: '';
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background: repeating-linear-gradient(
    0deg,
    transparent,
    transparent 2px,
    rgba(0,0,0,0.12) 2px,
    rgba(0,0,0,0.12) 4px
  );
  pointer-events: none;
  z-index: 9999;
}

/* Vignette */
.crt::after {
  content: '';
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background: radial-gradient(
    ellipse at center,
    transparent 60%,
    rgba(0,0,0,0.4) 100%
  );
  pointer-events: none;
  z-index: 9998;
}

/* Noise texture overlay */
.noise {
  position: fixed;
  top: -50%; left: -50%;
  width: 200%; height: 200%;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.03'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: 9997;
  animation: noise-shift 0.5s steps(3) infinite;
  opacity: 0.5;
}

@keyframes noise-shift {
  0% { transform: translate(0, 0); }
  33% { transform: translate(-5px, -5px); }
  66% { transform: translate(5px, 2px); }
  100% { transform: translate(0, 0); }
}

/* Screen curvature */
#screen {
  position: relative;
  max-width: 900px;
  margin: 0 auto;
  padding: 40px 30px;
  min-height: 100vh;
}

/* ─── TYPOGRAPHY ─── */

h1, h2, h3, .menu-item, .nav-label, .btn {
  text-transform: uppercase;
  letter-spacing: 2px;
}

h1 {
  font-size: 2rem;
  color: var(--fg-accent);
  text-shadow: 0 0 8px var(--glow), 0 0 20px rgba(255,255,255,0.08);
}

h2 {
  font-size: 1.4rem;
  color: var(--fg-bright);
  margin-bottom: 1rem;
}

h3 {
  font-size: 1.1rem;
  color: var(--fg-bright);
  margin-bottom: 0.5rem;
}

a {
  color: var(--fg-bright);
  text-decoration: none;
  border-bottom: 1px solid var(--fg-dim);
  transition: text-shadow 0.2s;
}

a:hover, a:focus {
  text-shadow: 0 0 8px var(--glow);
  color: var(--fg-accent);
}

/* ─── HEADER ─── */

.header {
  text-align: center;
  padding: 40px 0 20px;
  border-bottom: 1px solid var(--fg-dim);
  margin-bottom: 30px;
}

.header-dashes {
  color: var(--fg-dim);
  font-size: 1.4rem;
  letter-spacing: 6px;
}

.tagline {
  color: var(--fg-dim);
  font-size: 0.95rem;
  margin-top: 12px;
  letter-spacing: 1px;
}

/* ─── CURSOR BLINK ─── */

@keyframes blink {
  0%, 100% { opacity: 1; }
  50% { opacity: 0; }
}

.cursor-blink {
  animation: blink 1s step-end infinite;
}

/* ─── MAIN MENU ─── */

.menu {
  padding: 20px 0;
}

.menu-item {
  display: block;
  padding: 8px 0 8px 40px;
  font-size: 1.3rem;
  color: var(--fg);
  cursor: pointer;
  position: relative;
  transition: color 0.15s, text-shadow 0.15s;
  border: none;
  background: none;
  font-family: var(--font);
  text-align: left;
  width: 100%;
  letter-spacing: 2px;
}

.menu-item:hover,
.menu-item.active {
  color: var(--fg-accent);
  text-shadow: 0 0 8px var(--glow);
}

.menu-item .arrow {
  position: absolute;
  left: 8px;
  top: 50%;
  transform: translateY(-50%);
  opacity: 0;
  transition: opacity 0.1s;
  color: var(--fg-accent);
}

.menu-item.active .arrow {
  opacity: 1;
}

/* ─── KEYBOARD HINTS ─── */

.hints {
  border-top: 1px solid var(--fg-dim);
  padding-top: 20px;
  margin-top: 30px;
  color: var(--fg-dim);
  font-size: 0.9rem;
}

.hints div {
  margin-bottom: 4px;
}

.hint-key {
  display: inline-block;
  min-width: 100px;
}

/* ─── SECTIONS ─── */

.section {
  display: none;
  padding: 10px 0;
}

.section.visible {
  display: block;
  animation: fade-in 0.3s ease;
}

@keyframes fade-in {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

.back-btn {
  display: inline-block;
  cursor: pointer;
  color: var(--fg-dim);
  font-family: var(--font);
  font-size: 1rem;
  background: none;
  border: none;
  padding: 4px 0;
  margin-bottom: 20px;
  letter-spacing: 2px;
  text-transform: uppercase;
}

.back-btn:hover {
  color: var(--fg-accent);
  text-shadow: 0 0 6px var(--glow);
}

/* ─── FORM ELEMENTS ─── */

.term-input {
  background: transparent;
  border: 1px solid var(--fg-dim);
  color: var(--fg-bright);
  font-family: var(--font);
  font-size: 1.1rem;
  padding: 8px 12px;
  width: 100%;
  max-width: 500px;
  outline: none;
  transition: border-color 0.2s;
}

.term-input:focus {
  border-color: var(--fg-bright);
  text-shadow: 0 0 6px var(--glow);
}

.term-input::placeholder {
  color: var(--fg-dim);
}

.term-select {
  background: var(--bg);
  border: 1px solid var(--fg-dim);
  color: var(--fg-bright);
  font-family: var(--font);
  font-size: 1rem;
  padding: 6px 10px;
  outline: none;
  cursor: pointer;
  max-width: 500px;
  width: 100%;
}

.term-select:focus {
  border-color: var(--fg-bright);
}

.btn {
  background: transparent;
  border: 1px solid var(--fg);
  color: var(--fg-bright);
  font-family: var(--font);
  font-size: 1rem;
  padding: 8px 20px;
  cursor: pointer;
  letter-spacing: 2px;
  transition: all 0.15s;
  margin-right: 8px;
  margin-bottom: 8px;
}

.btn:hover, .btn:focus {
  background: var(--fg-bright);
  color: var(--bg);
  text-shadow: none;
}

.btn:active {
  background: var(--fg-accent);
}

.btn.active-btn {
  background: var(--fg);
  color: var(--bg);
  text-shadow: none;
}

label {
  display: block;
  color: var(--fg-dim);
  font-size: 0.9rem;
  margin-bottom: 4px;
  letter-spacing: 1px;
  text-transform: uppercase;
}

.form-row {
  margin-bottom: 16px;
}

.form-group {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 16px;
}

.form-group .form-col {
  flex: 1;
  min-width: 120px;
}

/* ─── BOX-DRAWING OUTPUT ─── */

.output-box {
  border: 1px solid var(--fg-dim);
  padding: 16px;
  margin: 16px 0;
  font-size: 0.95rem;
  white-space: pre-wrap;
  word-break: break-word;
  line-height: 1.6;
}

.output-box .label {
  color: var(--fg-dim);
}

.output-box .value {
  color: var(--fg-bright);
}

.output-title {
  color: var(--fg-accent);
  border-bottom: 1px solid var(--fg-dim);
  padding-bottom: 6px;
  margin-bottom: 10px;
  font-size: 1.05rem;
  letter-spacing: 2px;
  text-transform: uppercase;
}

/* ─── MATRIX TABLE ─── */

.matrix-table {
  font-size: 0.85rem;
  border-collapse: collapse;
  margin: 10px 0;
  width: 100%;
  overflow-x: auto;
  display: block;
}

.matrix-table th,
.matrix-table td {
  padding: 3px 8px;
  text-align: center;
  border: 1px solid #333;
  min-width: 32px;
  color: var(--fg);
}

.matrix-table th {
  color: var(--fg-dim);
  background: #111;
}

.matrix-table td.highlight {
  color: var(--fg-accent);
  text-shadow: 0 0 6px var(--glow);
}

/* ─── PIANO ROLL ─── */

.piano-roll {
  font-size: 0.8rem;
  line-height: 1.3;
  margin: 12px 0;
  overflow-x: auto;
  white-space: nowrap;
}

.piano-roll .voice-line {
  margin-bottom: 2px;
}

.voice-label {
  color: var(--fg-dim);
  display: inline-block;
  min-width: 90px;
}

.note-on { color: var(--fg-accent); }
.note-off { color: #222; }

/* ─── TRANSPORT CONTROLS ─── */

.transport {
  display: flex;
  gap: 8px;
  align-items: center;
  margin: 16px 0;
  flex-wrap: wrap;
}

.beat-counter {
  color: var(--fg-dim);
  font-size: 1rem;
  margin-left: 12px;
}

/* ─── ABOUT SECTION ─── */

.about-text {
  font-size: 1.05rem;
  line-height: 1.7;
}

.about-text .prompt {
  color: var(--fg-dim);
}

.about-text .highlight {
  color: var(--fg-accent);
}

/* ─── IMAGES ─── */

.theory-img {
  max-width: 100%;
  margin: 16px 0;
  border: 1px solid var(--fg-dim);
  filter: grayscale(100%) contrast(1.1);
}

/* ─── FOOTER ─── */

.footer {
  border-top: 1px solid var(--fg-dim);
  padding: 20px 0 40px;
  margin-top: 40px;
  text-align: center;
  color: var(--fg-dim);
  font-size: 0.85rem;
}

.footer a {
  color: var(--fg-dim);
  border-bottom-color: #333;
}

.footer a:hover {
  color: var(--fg);
}

/* ─── SOUND INDICATOR ─── */

.sound-indicator {
  position: fixed;
  top: 16px;
  right: 16px;
  color: var(--fg-dim);
  font-family: var(--font);
  font-size: 0.85rem;
  z-index: 100;
  letter-spacing: 1px;
}

/* ─── RANGE INPUT ─── */

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  max-width: 300px;
  height: 4px;
  background: var(--fg-dim);
  outline: none;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 14px;
  height: 14px;
  background: var(--fg-bright);
  border: none;
  cursor: pointer;
}

input[type="range"]::-moz-range-thumb {
  width: 14px;
  height: 14px;
  background: var(--fg-bright);
  border: none;
  cursor: pointer;
}

/* Number input */
input[type="number"] {
  background: transparent;
  border: 1px solid var(--fg-dim);
  color: var(--fg-bright);
  font-family: var(--font);
  font-size: 1rem;
  padding: 6px 10px;
  width: 100%;
  max-width: 140px;
  outline: none;
}

input[type="number"]:focus {
  border-color: var(--fg-bright);
}

/* ─── PHI DISPLAY ─── */

.phi-bar {
  display: inline-block;
  height: 10px;
  background: var(--fg-dim);
  margin-right: 2px;
  vertical-align: middle;
}

.phi-bar.close {
  background: var(--fg-bright);
}

/* ─── RESPONSIVE ─── */

@media (max-width: 600px) {
  html { font-size: 16px; }
  
  #screen {
    padding: 20px 16px;
  }
  
  .header { padding: 24px 0 16px; }
  
  h1 { font-size: 1.5rem; }
  
  .menu-item {
    font-size: 1.1rem;
    padding-left: 30px;
  }
  
  .menu-item .arrow {
    left: 4px;
  }
  
  .output-box {
    padding: 10px;
    font-size: 0.85rem;
  }
  
  .matrix-table th,
  .matrix-table td {
    padding: 2px 4px;
    font-size: 0.75rem;
    min-width: 24px;
  }
  
  .form-group {
    flex-direction: column;
  }
  
  .piano-roll {
    font-size: 0.7rem;
  }
  
  .voice-label {
    min-width: 70px;
  }
  
  .sound-indicator {
    top: 8px;
    right: 8px;
    font-size: 0.75rem;
  }
}

/* ─── LOADING ANIMATION ─── */

@keyframes type-in {
  from { width: 0; }
  to { width: 100%; }
}

.type-in {
  overflow: hidden;
  white-space: nowrap;
  animation: type-in 0.6s steps(20) forwards;
}

/* ─── STATUS LINE ─── */

.status-line {
  color: var(--fg-dim);
  font-size: 0.85rem;
  margin: 8px 0;
  letter-spacing: 1px;
}

.separator {
  color: var(--fg-dim);
  margin: 16px 0;
  letter-spacing: 4px;
  user-select: none;
}