/*
  CPU Scheduling — Interactive Learning Guide
  style.css
  
  Fonts loaded via Google Fonts in index.html:
    DM Sans       — headings, UI labels, buttons
    JetBrains Mono — code, data, formulas, Gantt labels
*/


/* ─────────────────────────────────────────
   DESIGN TOKENS
   All colors live here. Change one, changes everywhere.
───────────────────────────────────────── */
:root {
  --bg:      #0a0a0f;   /* page background */
  --surface: #111118;   /* card background */
  --surface2:#18181f;   /* slightly lighter surface (inputs, viz headers) */
  --border:  #2a2a38;   /* all borders */
  --accent:  #7c6aff;   /* purple — P1, foundations phase */
  --accent2: #ff6a6a;   /* red — P2, warnings, danger */
  --accent3: #6affb8;   /* green — P3, success, metrics */
  --accent4: #ffb86a;   /* orange — P4, highlights */
  --text:    #e8e8f0;   /* primary text */
  --muted:   #7878a0;   /* secondary text, labels */

  /* per-process colors used consistently throughout the page */
  --p1: #7c6aff;
  --p2: #ff6a6a;
  --p3: #6affb8;
  --p4: #ffb86a;
  --p5: #ff6adf;
}


/* ─────────────────────────────────────────
   RESET / BASE
───────────────────────────────────────── */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'DM Sans', sans-serif;
  overflow-x: hidden;
  display: flex;
  flex-direction: column;
  align-items: center;

}

h1, h2, h3 {
  font-family: 'Platypi', serif;
  font-weight: 700;
  letter-spacing: -0.5px;
}

code, .mono {
  font-family: 'JetBrains Mono', monospace;
}

/* thin scrollbar, dark-themed */
::-webkit-scrollbar { width: 4px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 2px; }


/* ─────────────────────────────────────────
   NOISE TEXTURE OVERLAY
   SVG fractal noise layered on the body
   using a fixed pseudo-element.
   Keeps things from looking too flat.
───────────────────────────────────────── */
body::before {
  content: '';
  position: fixed; inset: 0;
  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='0.04'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: 0;
  opacity: 0.4;
}


/* ─────────────────────────────────────────
   LAYOUT — SECTIONS
───────────────────────────────────────── */
.section {
  position: relative;
  padding: 100px 0 80px;
  z-index: 1;
  width: 100%;
}
/* divider between adjacent sections */
.section + .section { border-top: 1px solid var(--border); }


/* ─────────────────────────────────────────
   HERO — background decorations
───────────────────────────────────────── */
.grid-lines {
  position: absolute; inset: 0;
  background-image:
    linear-gradient(var(--border) 1px, transparent 1px),
    linear-gradient(90deg, var(--border) 1px, transparent 1px);
  background-size: 60px 60px;
  opacity: 0.3;
}

/* blurred gradient orb, used for ambient glow in hero */
.orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.12;
  pointer-events: none;
}


/* ─────────────────────────────────────────
   PHASE PROGRESS BAR  (fixed top strip)
───────────────────────────────────────── */
#phase-bar {
  position: fixed; top: 0; left: 0; right: 0;
  z-index: 200;
  background: rgba(10,10,15,0.92);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(12px);
  padding: 0 24px;
  height: 44px;
  display: flex; align-items: center; justify-content: center;
  gap: 0;
}

.phase-step {
  display: flex; align-items: center; gap: 8px;
  padding: 0 16px;
  font-size: 10px; font-weight: 700; letter-spacing: 1.5px;
  text-transform: uppercase; color: var(--muted);
  transition: color 0.3s;
  cursor: pointer;
}

.phase-step .phase-icon {
  width: 18px; height: 18px; border-radius: 50%;
  border: 1.5px solid var(--border);
  display: flex; align-items: center; justify-content: center;
  font-size: 9px; transition: all 0.3s;
  background: var(--bg);
}

/* state variations */
.phase-step.done              { color: var(--accent3); }
.phase-step.done .phase-icon  { background: var(--accent3); border-color: var(--accent3); color: #000; }
.phase-step.active            { color: var(--text); }
.phase-step.active .phase-icon{ border-color: var(--accent); background: #1e1a3a; color: var(--accent); }

.phase-sep {
  color: #2a2a38;
  font-size: 12px; font-weight: 300;
  padding: 0 4px;
}

@media (max-width: 640px) {
  .phase-step .phase-label { display: none; }
  .phase-step { padding: 0 8px; }
}


/* ─────────────────────────────────────────
   SIDE NAV  (fixed left dot navigation)
───────────────────────────────────────── */
#progress-nav {
  position: fixed; left: 24px; top: 50%;
  transform: translateY(-50%);
  z-index: 100;
  display: flex; flex-direction: column; gap: 4px;
}

.nav-group {
  display: flex; flex-direction: column; gap: 4px;
}

.nav-group + .nav-group {
  margin-top: 10px;
  padding-top: 10px;
  border-top: 1px solid var(--border);
}

.nav-group-label {
  font-size: 7px; font-weight: 800; letter-spacing: 2px;
  text-transform: uppercase; color: #333;
  padding-left: 2px;
  font-family: 'JetBrains Mono', monospace;
}

.nav-dot {
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--border); cursor: pointer;
  transition: all 0.3s; position: relative;
}

/* elongates on active */
.nav-dot.active { background: var(--accent); width: 8px; height: 24px; border-radius: 4px; }
.nav-dot:hover  { background: var(--muted); }

/* dot color shifts by phase when active */
.nav-dot.phase-foundations.active { background: var(--accent); }
.nav-dot.phase-scheduling.active  { background: var(--accent4); }
.nav-dot.phase-algorithms.active  { background: var(--accent2); }

/* hover tooltip */
.nav-dot .tooltip {
  position: absolute; left: 18px; top: 50%;
  transform: translateY(-50%);
  background: var(--surface); border: 1px solid var(--border);
  padding: 4px 10px; border-radius: 6px;
  font-size: 11px; white-space: nowrap;
  opacity: 0; pointer-events: none;
  transition: opacity 0.2s;
}
.nav-dot:hover .tooltip { opacity: 1; }

@media (max-width: 768px) { #progress-nav { display: none; } }
@media (max-width: 480px) { #phase-bar    { display: none; } }


/* ─────────────────────────────────────────
   STAGE BADGE  (small pill above section headings)
───────────────────────────────────────── */
.stage-badge {
  display: inline-flex; align-items: center; gap: 8px;
  background: #1a1a28; border: 1px solid var(--border);
  padding: 4px 14px; border-radius: 100px;
  font-size: 11px; font-weight: 700; letter-spacing: 2px;
  text-transform: uppercase; color: var(--muted);
  margin-bottom: 20px;
}
.stage-badge .dot { width: 6px; height: 6px; border-radius: 50%; }


/* ─────────────────────────────────────────
   THEORY CARD  (content cards with colored top stripe)
───────────────────────────────────────── */
.theory-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 28px 32px;
  position: relative;
  overflow: hidden;
}

/* the 2px gradient stripe at the top */
.theory-card::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0; height: 2px;
}
.theory-card.accent-purple::before { background: linear-gradient(90deg, var(--accent),  transparent); }
.theory-card.accent-red::before    { background: linear-gradient(90deg, var(--accent2), transparent); }
.theory-card.accent-green::before  { background: linear-gradient(90deg, var(--accent3), transparent); }
.theory-card.accent-orange::before { background: linear-gradient(90deg, var(--accent4), transparent); }


/* ─────────────────────────────────────────
   PHASE TRANSITION CARDS  (between phases)
───────────────────────────────────────── */
.phase-transition {
  padding: 80px 0;
  border-top: 1px solid var(--border);
  position: relative; z-index: 1;
}
.phase-transition-inner {
  max-width: 640px; margin: 0 auto;
  padding: 0 32px; text-align: center;
}
.phase-transition-badge {
  display: inline-flex; align-items: center; gap: 8px;
  margin-bottom: 24px;
  font-size: 10px; font-weight: 800; letter-spacing: 2px;
  text-transform: uppercase; color: var(--muted);
}
.phase-transition-badge .line { height: 1px; width: 32px; background: var(--border); }
.phase-transition p            { font-size: 18px; line-height: 1.7; color: var(--muted); font-weight: 400; }
.phase-transition strong       { color: var(--text); font-weight: 700; }
.phase-transition .next-btn {
  display: inline-flex; align-items: center; gap: 10px;
  margin-top: 28px; padding: 12px 28px; border-radius: 12px;
  border: 1px solid var(--border); background: var(--surface);
  color: var(--text); font-size: 13px; font-weight: 700;
  cursor: pointer; transition: all 0.2s;
  font-family: 'DM Sans', sans-serif; text-decoration: none;
}
.phase-transition .next-btn:hover {
  border-color: var(--accent); background: #1a1a2a;
  transform: translateY(-1px);
}


/* ─────────────────────────────────────────
   VIZ BOX  (container for interactive visualizations)
───────────────────────────────────────── */
.viz-box {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
}
.viz-header {
  padding: 14px 20px;
  border-bottom: 1px solid var(--border);
  display: flex; align-items: center; justify-content: space-between;
  background: var(--surface2);
}
.viz-title {
  font-size: 11px; font-weight: 700;
  letter-spacing: 2px; text-transform: uppercase;
  color: var(--muted);
}
.viz-body { padding: 24px; }


/* ─────────────────────────────────────────
   GANTT CHART BLOCKS
───────────────────────────────────────── */
.gantt-row { display: flex; align-items: center; gap: 0; }

.gantt-block {
  height: 48px;
  display: flex; align-items: center; justify-content: center;
  font-size: 13px; font-weight: 700;
  position: relative;
  transition: all 0.3s;
  border-radius: 4px;
  margin: 1px;
}

/* time tick labels underneath blocks */
.gantt-block .tick {
  position: absolute; bottom: -20px; left: 0;
  font-size: 10px; color: var(--muted);
  font-family: 'JetBrains Mono', monospace;
}
.gantt-block .tick-end {
  position: absolute; bottom: -20px; right: 0;
  font-size: 10px; color: var(--muted);
  font-family: 'JetBrains Mono', monospace;
}


/* ─────────────────────────────────────────
   PROCESS PILL  (colored label tag, e.g. "P1")
───────────────────────────────────────── */
.proc-pill {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 4px 10px; border-radius: 6px;
  font-size: 12px; font-weight: 700;
  font-family: 'JetBrains Mono', monospace;
}


/* ─────────────────────────────────────────
   METRIC PILL  (avg wait time, avg TAT badges)
───────────────────────────────────────── */
.metric-pill {
  display: flex; flex-direction: column; align-items: center;
  background: var(--surface2); border: 1px solid var(--border);
  border-radius: 12px; padding: 12px 20px; min-width: 100px;
}
.metric-pill .val { font-size: 22px; font-weight: 800; }
.metric-pill .lbl {
  font-size: 10px; color: var(--muted);
  letter-spacing: 1px; text-transform: uppercase; margin-top: 2px;
}


/* ─────────────────────────────────────────
   BUTTONS
───────────────────────────────────────── */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 10px 22px; border-radius: 10px;
  font-size: 13px; font-weight: 700;
  cursor: pointer; border: none; transition: all 0.2s;
  font-family: 'DM Sans', sans-serif;
}
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: #9080ff; transform: translateY(-1px); }
.btn-ghost   { background: var(--surface2); color: var(--text); border: 1px solid var(--border); }
.btn-ghost:hover { background: var(--border); }
.btn-danger  { background: var(--accent2); color: #fff; }
.btn-success { background: var(--accent3); color: #000; }


/* ─────────────────────────────────────────
   DATA TABLE  (results tables in simulators)
───────────────────────────────────────── */
.data-table { width: 100%; border-collapse: collapse; }
.data-table th {
  font-size: 10px; letter-spacing: 2px; text-transform: uppercase;
  color: var(--muted); padding: 10px 14px;
  text-align: left; border-bottom: 1px solid var(--border);
  font-family: 'JetBrains Mono', monospace;
}
.data-table td {
  padding: 10px 14px; font-size: 13px;
  font-family: 'JetBrains Mono', monospace;
  border-bottom: 1px solid #1e1e2a;
}


/* ─────────────────────────────────────────
   HIGHLIGHT BOX  (left-bordered callout)
───────────────────────────────────────── */
.highlight-box {
  background: #13131f;
  border-left: 3px solid var(--accent);
  padding: 14px 18px;
  border-radius: 0 10px 10px 0;
  font-size: 14px; line-height: 1.7;
}
.highlight-box.red    { border-left-color: var(--accent2); }
.highlight-box.green  { border-left-color: var(--accent3); }
.highlight-box.orange { border-left-color: var(--accent4); }


/* ─────────────────────────────────────────
   FORMULA  (monospace display for math)
───────────────────────────────────────── */
.formula {
  background: #0f0f18; border: 1px solid var(--border);
  border-radius: 10px; padding: 12px 20px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 13px; color: var(--accent3);
  display: inline-block;
}


/* ─────────────────────────────────────────
   ALGORITHM QUESTION CARD  (before algos section)
───────────────────────────────────────── */
.question-card {
  background: #0d0d18; border: 1px solid #2a2a48;
  border-radius: 20px; padding: 40px;
  position: relative; overflow: hidden;
}
/* the large decorative "?" in the background */
.question-card::before {
  content: '?';
  position: absolute; right: 32px; top: 16px;
  font-size: 120px; font-weight: 900;
  color: #ffffff06;
  font-family: 'DM Sans', sans-serif;
  line-height: 1;
}
.question-card-processes {
  display: grid; grid-template-columns: repeat(4, 1fr);
  gap: 12px; margin: 24px 0;
}
@media (max-width: 640px) {
  .question-card-processes { grid-template-columns: repeat(2, 1fr); }
}
.qcard-proc {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 12px; padding: 16px; text-align: center;
}


/* ─────────────────────────────────────────
   MISC UI COMPONENTS
───────────────────────────────────────── */

/* tab buttons in the comparison section */
.algo-tab {
  padding: 8px 18px; border-radius: 8px;
  font-size: 12px; font-weight: 700;
  cursor: pointer; border: 1px solid var(--border);
  color: var(--muted); background: var(--surface2);
  transition: all 0.2s; letter-spacing: 1px;
}
.algo-tab.active { color: #fff; border-color: var(--accent); background: #1e1a3a; }

/* number input used in RR quantum */
.styled-input {
  background: var(--surface2); border: 1px solid var(--border);
  color: var(--text); padding: 8px 14px; border-radius: 8px;
  font-family: 'JetBrains Mono', monospace; font-size: 13px;
  outline: none; width: 80px; text-align: center;
  transition: border-color 0.2s;
}
.styled-input:focus { border-color: var(--accent); }


/* ─────────────────────────────────────────
   READY QUEUE ITEM  (v4 addition)
   Used by renderRQ() in main.js
───────────────────────────────────────── */
.rq-item {
  border-radius: 8px;
  font-weight: 700;
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  padding: 5px 10px;
  border: 1px solid var(--border);
  transition: all 0.2s;
}


/* ─────────────────────────────────────────
   ALGORITHM CHOOSER BUTTON  (v4 addition)
   Used in comparison section
───────────────────────────────────────── */
.chooser-btn {
  cursor: pointer;
  transition: all 0.2s;
  font-family: 'DM Sans', sans-serif;
}

.chooser-btn:hover {
  background: var(--surface) !important;
  transform: translateX(4px);
}


/* ─────────────────────────────────────────
   ANIMATIONS
───────────────────────────────────────── */
@keyframes slideIn {
  from { opacity: 0; transform: translateX(-20px); }
  to   { opacity: 1; transform: translateX(0); }
}
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(20px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50%       { opacity: 0.4; }
}

.fade-up { animation: fadeUp 0.6s ease forwards; }