/* ══════════════════════════════════════════════════
   ADC Signal Processing Lab — Shared Design System
   ══════════════════════════════════════════════════ */
@import url('https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@400;500;700&family=DM+Sans:wght@300;400;500;600&display=swap');

:root {
  --bg:      #0f0f0f;
  --s1:      #171717;
  --s2:      #1f1f1f;
  --s3:      #282828;
  --s4:      #333333;
  --s5:      #404040;
  --border:  rgba(255,255,255,0.07);
  --border2: rgba(255,255,255,0.14);
  --border3: rgba(255,255,255,0.22);
  --text:    #e8e8e8;
  --muted:   #555;
  --muted2:  #888;
  --muted3:  #aaa;
  --blue:    #5b9cf6;
  --coral:   #ff6500;
  --green:   #4ade80;
  --red:     #f87171;
  --yellow:  #fbbf24;
  --purple:  #a78bfa;
  --mono: 'JetBrains Mono', monospace;
  --sans: 'DM Sans', sans-serif;
  --r: 10px; --r-sm: 6px; --r-lg: 16px; --r-xl: 24px;
  --shadow: 0 4px 24px rgba(0,0,0,0.4);
  --shadow-lg: 0 8px 48px rgba(0,0,0,0.6);
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body { font-family: var(--sans); background: var(--bg); color: var(--text); min-height: 100vh; overflow-x: hidden; line-height: 1.6; }

/* ── GRID BACKGROUND ── */
body::before {
  content: '';
  position: fixed; inset: 0;
  background-image: linear-gradient(rgba(255,255,255,0.02) 1px, transparent 1px),
                    linear-gradient(90deg, rgba(255,255,255,0.02) 1px, transparent 1px);
  background-size: 48px 48px;
  pointer-events: none; z-index: 0;
}

/* ── NAV ── */
nav {
  position: sticky; top: 0; z-index: 100;
  background: rgba(15,15,15,0.9);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: 0 32px;
  height: 56px;
  display: flex; align-items: center; justify-content: space-between;
}
.nav-logo {
  font-family: var(--mono); font-size: 13px; font-weight: 700;
  color: var(--text); text-decoration: none; letter-spacing: -0.3px;
  display: flex; align-items: center; gap: 8px;
}
.nav-logo .logo-dot {
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--blue); box-shadow: 0 0 8px var(--blue);
}
.nav-links { display: flex; gap: 4px; align-items: center; }
.nav-links a {
  font-size: 13px; color: var(--muted2); text-decoration: none;
  padding: 6px 12px; border-radius: var(--r-sm); transition: all 0.15s;
}
.nav-links a:hover { color: var(--text); background: var(--s3); }
.nav-links a.active { color: var(--text); }
.nav-cta {
  font-family: var(--mono); font-size: 11px; font-weight: 600;
  padding: 7px 16px; border-radius: var(--r-sm);
  background: var(--text); color: var(--bg);
  text-decoration: none; letter-spacing: 0.3px;
  transition: opacity 0.15s;
}
.nav-cta:hover { opacity: 0.85; }

/* ── TYPOGRAPHY ── */
h1 { font-size: clamp(28px, 5vw, 52px); font-weight: 600; line-height: 1.1; letter-spacing: -1px; }
h2 { font-size: clamp(20px, 3vw, 30px); font-weight: 500; letter-spacing: -0.5px; }
h3 { font-size: 16px; font-weight: 500; }
h4 { font-size: 13px; font-weight: 600; font-family: var(--mono); text-transform: uppercase; letter-spacing: 1px; color: var(--muted2); }
p  { color: var(--muted3); line-height: 1.75; }

/* ── LAYOUT ── */
.container { max-width: 1160px; margin: 0 auto; padding: 0 24px; position: relative; z-index: 1; }
.section { padding: 80px 0; }
.section-sm { padding: 48px 0; }

/* ── BUTTONS ── */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 10px 20px; border-radius: var(--r); border: none;
  font-family: var(--sans); font-size: 14px; font-weight: 500;
  cursor: pointer; transition: all 0.15s; text-decoration: none;
  white-space: nowrap;
}
.btn-primary { background: var(--text); color: var(--bg); }
.btn-primary:hover { opacity: 0.85; transform: translateY(-1px); }
.btn-outline { background: transparent; color: var(--text); border: 1px solid var(--border2); }
.btn-outline:hover { background: var(--s3); border-color: var(--border3); }
.btn-ghost { background: var(--s2); color: var(--muted2); border: 1px solid var(--border); }
.btn-ghost:hover { background: var(--s3); color: var(--text); }
.btn-danger { background: rgba(248,113,113,0.12); color: var(--red); border: 1px solid rgba(248,113,113,0.2); }
.btn-danger:hover { background: rgba(248,113,113,0.2); }
.btn-sm { padding: 6px 12px; font-size: 12px; border-radius: var(--r-sm); }
.btn-lg { padding: 14px 28px; font-size: 16px; border-radius: var(--r); }
.btn:disabled { opacity: 0.4; cursor: not-allowed; transform: none; }

/* ── CARDS ── */
.card {
  background: var(--s1); border: 1px solid var(--border);
  border-radius: var(--r-lg); overflow: hidden;
}
.card-header {
  padding: 12px 16px; background: var(--s2);
  border-bottom: 1px solid var(--border);
  display: flex; align-items: center; gap: 8px;
}
.card-header h3 { font-family: var(--mono); font-size: 10px; font-weight: 600; color: var(--muted2); letter-spacing: 1px; text-transform: uppercase; }
.card-body { padding: 16px; }

/* ── STATUS DOTS ── */
.dot { width: 7px; height: 7px; border-radius: 50%; flex-shrink: 0; }
.dot-white  { background: var(--text);   box-shadow: 0 0 5px rgba(255,255,255,0.3); }
.dot-blue   { background: var(--blue);   box-shadow: 0 0 5px rgba(91,156,246,0.5); }
.dot-coral  { background: var(--coral);  box-shadow: 0 0 5px rgba(255,101,0,0.5); }
.dot-green  { background: var(--green);  box-shadow: 0 0 5px rgba(74,222,128,0.5); }
.dot-yellow { background: var(--yellow); box-shadow: 0 0 5px rgba(251,191,36,0.5); }
.dot-red    { background: var(--red);    box-shadow: 0 0 5px rgba(248,113,113,0.5); }
@keyframes pulse-dot { 0%,100%{opacity:1} 50%{opacity:.4} }
.dot-pulse { animation: pulse-dot 2s infinite; }

/* ── FORM ELEMENTS ── */
.form-group { margin-bottom: 16px; }
.form-label { display: block; font-size: 12px; font-weight: 500; color: var(--muted2); margin-bottom: 6px; font-family: var(--mono); letter-spacing: 0.3px; }
.form-input, .form-select, .form-textarea {
  width: 100%; background: var(--s2); border: 1px solid var(--border2);
  color: var(--text); padding: 9px 12px; border-radius: var(--r-sm);
  font-family: var(--sans); font-size: 14px; outline: none;
  transition: border-color 0.15s;
}
.form-input:focus, .form-select:focus, .form-textarea:focus { border-color: var(--border3); }
.form-textarea { resize: vertical; min-height: 100px; line-height: 1.6; }
.form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
@media (max-width: 600px) { .form-grid { grid-template-columns: 1fr; } }

/* ── SLIDER ── */
input[type=range] { -webkit-appearance: none; width: 100%; height: 4px; background: var(--s3); border-radius: 4px; outline: none; cursor: pointer; }
input[type=range]::-webkit-slider-thumb { -webkit-appearance: none; width: 16px; height: 16px; border-radius: 50%; background: var(--text); border: 2px solid var(--s1); cursor: pointer; transition: transform 0.1s; }
input[type=range]::-webkit-slider-thumb:hover { transform: scale(1.2); }

/* ── TABS ── */
.tabs { display: flex; gap: 3px; background: var(--s2); padding: 3px; border-radius: var(--r-sm); }
.tab { flex: 1; padding: 7px 10px; font-size: 12px; font-family: var(--mono); font-weight: 500; text-align: center; border-radius: 6px; cursor: pointer; color: var(--muted); border: none; background: transparent; transition: all 0.15s; }
.tab.active { background: var(--s4); color: var(--text); border: 1px solid var(--border2); }
.tab:hover:not(.active) { color: var(--muted2); }
.tab-content { display: none; }
.tab-content.active { display: block; }

/* ── TABLE ── */
.data-table { width: 100%; border-collapse: collapse; font-size: 13px; }
.data-table th { font-family: var(--mono); font-size: 10px; font-weight: 600; color: var(--muted2); text-transform: uppercase; letter-spacing: 0.8px; padding: 8px 12px; text-align: left; border-bottom: 1px solid var(--border2); background: var(--s2); }
.data-table td { padding: 10px 12px; border-bottom: 1px solid var(--border); color: var(--muted3); font-family: var(--mono); font-size: 12px; }
.data-table tr:hover td { background: var(--s2); color: var(--text); }
.data-table tr:last-child td { border-bottom: none; }

/* ── BADGE ── */
.badge { display: inline-block; font-family: var(--mono); font-size: 10px; font-weight: 700; padding: 3px 8px; border-radius: 4px; letter-spacing: 0.5px; }
.badge-blue   { background: rgba(91,156,246,0.12);  color: var(--blue);   border: 1px solid rgba(91,156,246,0.25); }
.badge-green  { background: rgba(74,222,128,0.12);  color: var(--green);  border: 1px solid rgba(74,222,128,0.25); }
.badge-coral  { background: rgba(255,101,0,0.12);   color: var(--coral);  border: 1px solid rgba(255,101,0,0.25); }
.badge-yellow { background: rgba(251,191,36,0.12);  color: var(--yellow); border: 1px solid rgba(251,191,36,0.25); }
.badge-red    { background: rgba(248,113,113,0.12); color: var(--red);    border: 1px solid rgba(248,113,113,0.25); }

/* ── DIVIDER ── */
.divider { height: 1px; background: var(--border); margin: 16px 0; }

/* ── STEP INDICATOR ── */
.step-bar {
  display: flex; align-items: center;
  background: var(--s1); border-bottom: 1px solid var(--border);
  padding: 0 32px; overflow-x: auto; gap: 0;
}
.step-item {
  display: flex; align-items: center; gap: 10px;
  padding: 16px 20px; cursor: pointer; border-bottom: 2px solid transparent;
  transition: all 0.2s; white-space: nowrap; color: var(--muted2);
  font-size: 13px;
}
.step-item:hover { color: var(--muted3); }
.step-item.active { color: var(--text); border-bottom-color: var(--text); }
.step-item.done { color: var(--green); }
.step-item.done .step-num { background: var(--green); color: var(--bg); }
.step-num {
  width: 22px; height: 22px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-family: var(--mono); font-size: 10px; font-weight: 700;
  background: var(--s3); color: var(--muted2); flex-shrink: 0;
  transition: all 0.2s;
}
.step-item.active .step-num { background: var(--text); color: var(--bg); }
.step-connector { width: 24px; height: 1px; background: var(--border); flex-shrink: 0; }

/* ── UPLOAD ZONE ── */
.upload-zone {
  border: 2px dashed rgba(255,255,255,0.12); border-radius: var(--r);
  padding: 28px 20px; text-align: center; cursor: pointer;
  transition: all 0.2s; background: rgba(255,255,255,0.02);
  position: relative;
}
.upload-zone:hover, .upload-zone.dragover { border-color: rgba(255,255,255,0.3); background: rgba(255,255,255,0.04); }
.upload-zone input[type=file] { position: absolute; inset: 0; opacity: 0; cursor: pointer; width: 100%; height: 100%; }
.upload-zone .up-icon { font-size: 28px; display: block; margin-bottom: 10px; }
.upload-zone strong { display: block; font-size: 14px; margin-bottom: 4px; }
.upload-zone p { font-size: 12px; color: var(--muted2); }

/* ── RANGE CONTROL ROW ── */
.ctrl { margin-bottom: 18px; }
.ctrl-row { display: flex; align-items: center; justify-content: space-between; margin-bottom: 7px; font-size: 12px; color: var(--muted2); gap: 6px; }
.ctrl-val { font-family: var(--mono); font-size: 12px; font-weight: 700; color: var(--text); background: var(--s3); border: 1px solid var(--border2); padding: 2px 8px; border-radius: 4px; min-width: 52px; text-align: center; flex-shrink: 0; }

/* ── STAT CARD ── */
.stat-card { background: var(--s2); border: 1px solid var(--border); border-radius: var(--r-sm); padding: 12px; text-align: center; }
.stat-label { font-size: 10px; color: var(--muted); font-family: var(--mono); text-transform: uppercase; letter-spacing: 0.5px; margin-bottom: 4px; }
.stat-val { font-family: var(--mono); font-size: 20px; font-weight: 700; color: var(--text); line-height: 1; }
.stat-sub { font-size: 10px; color: var(--muted); margin-top: 2px; }

/* ── ALERT ── */
.alert { padding: 10px 14px; border-radius: var(--r-sm); font-size: 13px; display: flex; align-items: flex-start; gap: 8px; }
.alert-info    { background: rgba(91,156,246,0.08);  border: 1px solid rgba(91,156,246,0.2);  color: #93c5fd; }
.alert-success { background: rgba(74,222,128,0.08);  border: 1px solid rgba(74,222,128,0.2);  color: #86efac; }
.alert-warn    { background: rgba(251,191,36,0.08);  border: 1px solid rgba(251,191,36,0.2);  color: #fde68a; }

/* ── RECORD BUTTON ── */
.rec-btn {
  width: 64px; height: 64px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 24px; cursor: pointer; border: none;
  transition: all 0.2s; margin: 0 auto;
}
.rec-btn.idle    { background: var(--s3); border: 2px solid var(--border2); }
.rec-btn.idle:hover { background: rgba(248,113,113,0.15); border-color: var(--red); }
.rec-btn.recording { background: rgba(248,113,113,0.2); border: 2px solid var(--red); animation: rec-pulse 1s ease-in-out infinite; }
.rec-btn.done    { background: rgba(74,222,128,0.12); border: 2px solid var(--green); }
@keyframes rec-pulse { 0%,100%{box-shadow:0 0 0 0 rgba(248,113,113,0.4)} 50%{box-shadow:0 0 0 12px rgba(248,113,113,0)} }

/* ── PRINT ── */
@media print {
  nav, .step-bar, .no-print { display: none !important; }
  body { background: white; color: black; }
  .card { border: 1px solid #ccc; }
}

/* ── SCROLLBAR ── */
::-webkit-scrollbar { width: 5px; height: 5px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--s4); border-radius: 3px; }