/* ============================================================
   USB CDC Terminal — Design System & Styles
   ============================================================ */

/* ---- CSS Custom Properties ---- */
:root {
  /* Colors — Deep Navy / Cyan accent palette */
  --clr-bg:          hsl(225, 30%, 6%);
  --clr-surface:     hsl(225, 25%, 10%);
  --clr-surface-2:   hsl(225, 22%, 14%);
  --clr-border:      hsl(225, 18%, 18%);
  --clr-border-subtle: hsl(225, 18%, 14%);

  --clr-text:        hsl(210, 20%, 88%);
  --clr-text-muted:  hsl(210, 15%, 55%);
  --clr-text-dim:    hsl(210, 10%, 38%);

  --clr-accent:      hsl(174, 72%, 52%);
  --clr-accent-dim:  hsl(174, 60%, 28%);
  --clr-accent-glow: hsla(174, 72%, 52%, .25);
  --clr-accent-bg:   hsla(174, 72%, 52%, .08);

  --clr-danger:      hsl(0, 72%, 58%);
  --clr-danger-dim:  hsl(0, 50%, 35%);
  --clr-warning:     hsl(38, 92%, 55%);
  --clr-success:     hsl(142, 64%, 48%);

  --clr-tx:          hsl(38, 92%, 62%);
  --clr-rx:          hsl(174, 72%, 52%);

  /* Typography */
  --ff-sans:  'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --ff-mono:  'JetBrains Mono', 'Fira Code', 'Cascadia Code', 'Menlo', monospace;

  --fs-xs:   0.6875rem;
  --fs-sm:   0.75rem;
  --fs-base: 0.8125rem;
  --fs-md:   0.9375rem;
  --fs-lg:   1.125rem;
  --fs-xl:   1.5rem;

  /* Spacing */
  --sp-1: 4px;
  --sp-2: 8px;
  --sp-3: 12px;
  --sp-4: 16px;
  --sp-5: 20px;
  --sp-6: 24px;
  --sp-8: 32px;

  /* Radii */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --radius-xl: 20px;

  /* Shadows */
  --shadow-sm:  0 1px 3px hsla(0,0%,0%,.25);
  --shadow-md:  0 4px 16px hsla(0,0%,0%,.35);
  --shadow-lg:  0 8px 32px hsla(0,0%,0%,.4);
  --shadow-glow: 0 0 20px var(--clr-accent-glow);

  /* Transitions */
  --ease-out: cubic-bezier(.22, 1, .36, 1);
  --dur-fast: 150ms;
  --dur-med:  250ms;
  --dur-slow: 400ms;

  /* Layout */
  --sidebar-w: 260px;
  --topbar-h:  52px;
}


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

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--ff-sans);
  background: var(--clr-bg);
  color: var(--clr-text);
  overflow: hidden;
  height: 100vh;
  width: 100vw;
}

a { color: var(--clr-accent); }


/* ---- Background Effects ---- */
.bg-grid {
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(hsla(174,72%,52%,.03) 1px, transparent 1px),
    linear-gradient(90deg, hsla(174,72%,52%,.03) 1px, transparent 1px);
  background-size: 60px 60px;
  pointer-events: none;
  z-index: 0;
}

.bg-glow {
  position: fixed;
  border-radius: 50%;
  filter: blur(120px);
  pointer-events: none;
  z-index: 0;
}

.bg-glow--1 {
  width: 500px; height: 500px;
  background: hsla(174, 72%, 52%, .06);
  top: -120px; left: -100px;
  animation: float 20s ease-in-out infinite;
}

.bg-glow--2 {
  width: 400px; height: 400px;
  background: hsla(260, 60%, 50%, .05);
  bottom: -80px; right: -60px;
  animation: float 25s ease-in-out infinite reverse;
}

@keyframes float {
  0%, 100% { transform: translate(0, 0); }
  33%      { transform: translate(30px, -20px); }
  66%      { transform: translate(-20px, 15px); }
}


/* ---- App Shell ---- */
#app {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  height: 100vh;
}


/* ============================================================
   TOP BAR
   ============================================================ */
#topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--topbar-h);
  padding: 0 var(--sp-5);
  background: hsla(225, 25%, 10%, .7);
  backdrop-filter: blur(18px) saturate(1.6);
  -webkit-backdrop-filter: blur(18px) saturate(1.6);
  border-bottom: 1px solid var(--clr-border-subtle);
  flex-shrink: 0;
}

.topbar__brand {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
}

.topbar__menu {
  display: none;
  align-items: center;
  justify-content: center;
  width: 32px; height: 32px;
  margin-left: calc(var(--sp-2) * -1);
  padding: 0;
  background: none;
  border: none;
  border-radius: var(--radius-sm);
  color: var(--clr-text-muted);
  cursor: pointer;
  transition: color var(--dur-fast) var(--ease-out),
              background var(--dur-fast) var(--ease-out);
}

.topbar__menu svg {
  width: 20px; height: 20px;
}

.topbar__menu:hover {
  color: var(--clr-text);
  background: var(--clr-surface-2);
}

.sidebar-backdrop {
  display: none;
}

.topbar__icon {
  width: 24px; height: 24px;
  color: var(--clr-accent);
  filter: drop-shadow(0 0 6px var(--clr-accent-glow));
}

.topbar__title {
  font-size: var(--fs-md);
  font-weight: 600;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, var(--clr-text), var(--clr-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.topbar__right {
  display: flex;
  align-items: center;
  gap: var(--sp-4);
}

.topbar__status {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
}

.topbar__home {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  padding: var(--sp-1) var(--sp-3);
  border-radius: var(--radius-sm);
  color: var(--clr-text-muted);
  font-size: var(--fs-sm);
  font-weight: 500;
  text-decoration: none;
  transition: color var(--dur-fast) var(--ease-out),
              background var(--dur-fast) var(--ease-out);
}

.topbar__home svg {
  width: 14px; height: 14px;
  flex-shrink: 0;
}

.topbar__home:hover {
  color: var(--clr-text);
  background: var(--clr-surface-2);
}

.topbar__home:focus-visible {
  outline: 2px solid var(--clr-accent);
  outline-offset: 2px;
}

.status-dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  transition: background var(--dur-med) var(--ease-out),
              box-shadow var(--dur-med) var(--ease-out);
}

.status-dot--disconnected {
  background: var(--clr-text-dim);
}

.status-dot--connecting {
  background: var(--clr-warning);
  box-shadow: 0 0 8px hsla(38, 92%, 55%, .5);
  animation: pulse 1.2s ease-in-out infinite;
}

.status-dot--connected {
  background: var(--clr-success);
  box-shadow: 0 0 8px hsla(142, 64%, 48%, .5);
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50%      { opacity: .4; }
}

.status-label {
  font-size: var(--fs-xs);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--clr-text-muted);
}


/* ============================================================
   MAIN LAYOUT
   ============================================================ */
#main {
  display: flex;
  flex: 1;
  min-height: 0;
}


/* ============================================================
   SIDEBAR
   ============================================================ */
#sidebar {
  width: var(--sidebar-w);
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  padding: var(--sp-4);
  gap: var(--sp-3);
  background: hsla(225, 25%, 9%, .65);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-right: 1px solid var(--clr-border-subtle);
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: var(--clr-border) transparent;
}

.sidebar__heading {
  font-size: var(--fs-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .08em;
  color: var(--clr-text-muted);
  margin-bottom: var(--sp-2);
}

.sidebar__section {
  display: flex;
  flex-direction: column;
  gap: var(--sp-2);
}

.sidebar__help {
  min-height: 0;
}

.sidebar__divider {
  border: none;
  border-top: 1px solid var(--clr-border-subtle);
  margin: var(--sp-1) 0;
}

.sidebar__stats {
  display: flex;
  gap: var(--sp-3);
  margin-top: auto;
  padding-top: var(--sp-3);
}


/* ---- Form Fields ---- */
.field {
  display: flex;
  flex-direction: column;
  gap: var(--sp-1);
}

.field--inline {
  flex-direction: row;
  align-items: center;
  gap: var(--sp-2);
}

.advanced {
  margin-bottom: var(--sp-4, 16px);
}

.advanced__summary {
  cursor: pointer;
  list-style: none;
  padding: 6px 0;
  color: var(--clr-text-muted);
  font-size: var(--fs-xs);
  font-weight: 500;
}

.advanced__summary::-webkit-details-marker { display: none; }

.advanced__summary::before {
  content: "▸";
  display: inline-block;
  width: 1em;
  transition: transform 140ms ease;
}

.advanced[open] > .advanced__summary::before { transform: rotate(90deg); }

.advanced__summary:hover { color: var(--clr-text); }

.advanced__note {
  margin: 0 0 10px;
  color: var(--clr-text-dim, var(--clr-text-muted));
  font-size: var(--fs-xs);
  line-height: 1.5;
}

.field__label {
  font-size: var(--fs-xs);
  font-weight: 500;
  color: var(--clr-text-muted);
}

.field__label--inline {
  cursor: pointer;
  user-select: none;
}

.field__select {
  appearance: none;
  background: var(--clr-surface-2);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-sm);
  padding: var(--sp-2) var(--sp-3);
  padding-right: var(--sp-6);
  font-family: var(--ff-mono);
  font-size: var(--fs-sm);
  color: var(--clr-text);
  cursor: pointer;
  transition: border-color var(--dur-fast) var(--ease-out),
              box-shadow var(--dur-fast) var(--ease-out);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%236b7280' stroke-width='2'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 8px center;
}

.field__select:focus {
  outline: none;
  border-color: var(--clr-accent);
  box-shadow: 0 0 0 3px var(--clr-accent-glow);
}

.field__select option {
  background: var(--clr-surface);
  color: var(--clr-text);
}


/* ---- Toggle Switch ---- */
.toggle {
  position: relative;
  display: inline-flex;
  cursor: pointer;
  flex-shrink: 0;
}

.toggle input {
  position: absolute;
  opacity: 0;
  width: 0; height: 0;
}

.toggle__track {
  width: 36px; height: 20px;
  border-radius: 10px;
  background: var(--clr-surface-2);
  border: 1px solid var(--clr-border);
  position: relative;
  transition: background var(--dur-med) var(--ease-out),
              border-color var(--dur-med) var(--ease-out);
}

.toggle__track::after {
  content: '';
  position: absolute;
  width: 14px; height: 14px;
  border-radius: 50%;
  background: var(--clr-text-muted);
  top: 2px; left: 2px;
  transition: transform var(--dur-med) var(--ease-out),
              background var(--dur-med) var(--ease-out);
}

.toggle input:checked + .toggle__track {
  background: var(--clr-accent-dim);
  border-color: var(--clr-accent);
}

.toggle input:checked + .toggle__track::after {
  transform: translateX(16px);
  background: var(--clr-accent);
}

.toggle input:focus-visible + .toggle__track {
  box-shadow: 0 0 0 3px var(--clr-accent-glow);
}


/* ---- Buttons ---- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--sp-2);
  padding: var(--sp-2) var(--sp-4);
  border: none;
  border-radius: var(--radius-sm);
  font-family: var(--ff-sans);
  font-size: var(--fs-sm);
  font-weight: 600;
  cursor: pointer;
  transition: all var(--dur-fast) var(--ease-out);
  user-select: none;
}

.btn__icon {
  width: 16px; height: 16px;
  flex-shrink: 0;
}

.btn--primary {
  background: linear-gradient(135deg, var(--clr-accent), hsl(190, 65%, 45%));
  color: hsl(225, 30%, 8%);
  box-shadow: 0 2px 8px var(--clr-accent-glow);
}

.btn--primary:hover {
  box-shadow: 0 4px 18px var(--clr-accent-glow), var(--shadow-glow);
  transform: translateY(-1px);
  filter: brightness(1.1);
}

.btn--primary:active {
  transform: translateY(0);
  filter: brightness(.95);
}

.btn--primary.btn--danger {
  background: linear-gradient(135deg, var(--clr-danger), hsl(15, 65%, 50%));
  box-shadow: 0 2px 8px hsla(0, 72%, 58%, .25);
}

.btn--primary.btn--danger:hover {
  box-shadow: 0 4px 18px hsla(0, 72%, 58%, .35);
}

.btn--ghost {
  background: transparent;
  color: var(--clr-text-muted);
  border: 1px solid var(--clr-border);
}

.btn--ghost:hover {
  background: var(--clr-accent-bg);
  border-color: var(--clr-accent-dim);
  color: var(--clr-accent);
}


/* ---- Stats ---- */
.stat {
  display: flex;
  flex-direction: column;
  align-items: center;
  flex: 1;
  padding: var(--sp-2);
  background: var(--clr-surface-2);
  border-radius: var(--radius-sm);
  border: 1px solid var(--clr-border-subtle);
}

.stat__label {
  font-size: var(--fs-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .08em;
  color: var(--clr-text-dim);
}

.stat__value {
  font-family: var(--ff-mono);
  font-size: var(--fs-md);
  font-weight: 600;
}

.stat__value--tx { color: var(--clr-tx); }
.stat__value--rx { color: var(--clr-rx); }

.command-help__status {
  font-size: var(--fs-xs);
  color: var(--clr-text-muted);
}

.command-help__text {
  min-height: 120px;
  max-height: 220px;
  overflow: auto;
  padding: var(--sp-3);
  background: var(--clr-surface-2);
  border: 1px solid var(--clr-border-subtle);
  border-radius: var(--radius-sm);
  color: var(--clr-text);
  font-family: var(--ff-mono);
  font-size: var(--fs-xs);
  line-height: 1.6;
  white-space: pre-wrap;
  word-break: break-word;
  scrollbar-width: thin;
  scrollbar-color: var(--clr-border) transparent;
}


/* ============================================================
   TERMINAL PANEL
   ============================================================ */
#terminal-panel {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.terminal {
  flex: 1;
  overflow-y: auto;
  padding: var(--sp-4);
  font-family: var(--ff-mono);
  font-size: var(--fs-sm);
  line-height: 1.7;
  scroll-behavior: smooth;
  scrollbar-width: thin;
  scrollbar-color: var(--clr-border) transparent;
}

.terminal::-webkit-scrollbar {
  width: 6px;
}
.terminal::-webkit-scrollbar-track {
  background: transparent;
}
.terminal::-webkit-scrollbar-thumb {
  background: var(--clr-border);
  border-radius: 3px;
}

/* Welcome Screen */
.terminal__welcome {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100%;
  text-align: center;
  color: var(--clr-text-dim);
  gap: var(--sp-3);
  animation: fadeIn var(--dur-slow) var(--ease-out);
}

.terminal__welcome-icon {
  width: 64px; height: 64px;
  color: var(--clr-accent);
  opacity: .3;
  filter: drop-shadow(0 0 12px var(--clr-accent-glow));
}

.terminal__welcome h2 {
  font-family: var(--ff-sans);
  font-size: var(--fs-lg);
  font-weight: 600;
  color: var(--clr-text-muted);
}

.terminal__welcome p {
  font-family: var(--ff-sans);
  font-size: var(--fs-base);
}

.terminal__welcome-hint {
  margin-top: var(--sp-2);
  font-size: var(--fs-sm) !important;
  opacity: .6;
}

.terminal__welcome-hint strong {
  color: var(--clr-accent);
}

.terminal__output {
  display: none;
}

.terminal__output.active {
  display: block;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}


/* ---- Terminal Lines ---- */
.term-line {
  display: flex;
  gap: var(--sp-2);
  padding: 1px 0;
  animation: lineIn var(--dur-fast) var(--ease-out);
  white-space: pre-wrap;
  word-break: break-all;
}

@keyframes lineIn {
  from { opacity: 0; transform: translateX(-4px); }
  to   { opacity: 1; transform: translateX(0); }
}

.term-line__ts {
  color: var(--clr-text-dim);
  flex-shrink: 0;
  user-select: none;
  font-size: var(--fs-xs);
  min-width: 70px;
}

.term-line__dir {
  font-weight: 600;
  flex-shrink: 0;
  user-select: none;
  min-width: 22px;
  text-align: center;
}

.term-line__dir--tx {
  color: var(--clr-tx);
}

.term-line__dir--rx {
  color: var(--clr-rx);
}

.term-line__dir--sys {
  color: var(--clr-accent);
}

.term-line__msg {
  flex: 1;
}

.term-line--sys {
  color: var(--clr-text-muted);
  font-style: italic;
}

.term-line--sys .term-line__msg {
  color: var(--clr-text-muted);
}

.term-line--error {
  color: var(--clr-danger);
}

.term-line--error .term-line__msg {
  color: var(--clr-danger);
}

.term-hex {
  color: var(--clr-text-dim);
  font-size: var(--fs-xs);
  margin-left: 92px;
  padding: 0 0 2px;
  border-bottom: 1px solid var(--clr-border-subtle);
}


/* ============================================================
   INPUT BAR
   ============================================================ */
.input-bar {
  padding: var(--sp-3) var(--sp-4);
  background: hsla(225, 25%, 8%, .8);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-top: 1px solid var(--clr-border-subtle);
}

.input-bar__wrapper {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
  background: var(--clr-surface-2);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-md);
  padding: var(--sp-2) var(--sp-3);
  transition: border-color var(--dur-fast) var(--ease-out),
              box-shadow var(--dur-fast) var(--ease-out);
}

.input-bar__wrapper:focus-within {
  border-color: var(--clr-accent);
  box-shadow: 0 0 0 3px var(--clr-accent-glow);
}

.input-bar__prompt {
  color: var(--clr-accent);
  font-family: var(--ff-mono);
  font-weight: 600;
  font-size: var(--fs-base);
  user-select: none;
}

.input-bar__input {
  flex: 1;
  background: transparent;
  border: none;
  outline: none;
  font-family: var(--ff-mono);
  font-size: var(--fs-sm);
  color: var(--clr-text);
}

.input-bar__input::placeholder {
  color: var(--clr-text-dim);
}

.input-bar__input:disabled {
  opacity: .4;
  cursor: not-allowed;
}

.input-bar__controls {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
}

.input-bar__line-ending {
  appearance: none;
  background: var(--clr-surface);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-sm);
  padding: 2px 6px;
  font-family: var(--ff-mono);
  font-size: var(--fs-xs);
  color: var(--clr-text-muted);
  cursor: pointer;
}

.input-bar__line-ending:focus {
  outline: none;
  border-color: var(--clr-accent);
}

.btn--send {
  width: 32px; height: 32px;
  padding: 0;
  background: var(--clr-accent);
  color: hsl(225, 30%, 8%);
  border: none;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--dur-fast) var(--ease-out);
}

.btn--send:hover:not(:disabled) {
  filter: brightness(1.15);
  box-shadow: 0 0 12px var(--clr-accent-glow);
}

.btn--send:disabled {
  opacity: .3;
  cursor: not-allowed;
}


/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 768px) {
  :root {
    --sidebar-w: 220px;
  }

  .topbar__menu {
    display: inline-flex;
  }

  /* Keep the icon, drop the word, so the topbar still fits at phone width. */
  .topbar__home-label {
    display: none;
  }

  .topbar__right {
    gap: var(--sp-2);
  }

  #sidebar {
    position: fixed;
    left: 0;
    top: var(--topbar-h);
    bottom: 0;
    z-index: 10;
    transform: translateX(-100%);
    transition: transform var(--dur-med) var(--ease-out);
  }

  #sidebar.open {
    transform: translateX(0);
    box-shadow: var(--shadow-lg, 0 8px 32px hsla(225, 40%, 2%, .6));
  }

  .sidebar-backdrop.is-visible {
    display: block;
    position: fixed;
    left: 0;
    right: 0;
    top: var(--topbar-h);
    bottom: 0;
    z-index: 9;
    background: hsla(225, 40%, 3%, .6);
    backdrop-filter: blur(2px);
    -webkit-backdrop-filter: blur(2px);
  }
}

@media (prefers-reduced-motion: reduce) {
  #sidebar {
    transition: none;
  }
}