@import url('https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@400;600;700&family=Bricolage+Grotesque:wght@300;400;500;600;700;800&display=swap');

/* ─── TOKENS ────────────────────────────────────────────────── */
:root {
  --bg:        #0b0d12;
  --bg2:       #111318;
  --bg3:       #181b24;
  --bg4:       #1e2230;
  --border:    #252a38;
  --border2:   #2e3447;

  --text:      #e2e6f0;
  --text2:     #9aa3b8;
  --text3:     #5a6480;

  --green:     #00e5a0;
  --green-dim: rgba(0,229,160,0.12);
  --blue:      #4b8eff;
  --blue-dim:  rgba(75,142,255,0.12);
  --amber:     #ffb547;
  --amber-dim: rgba(255,181,71,0.12);
  --red:       #ff5c5c;
  --red-dim:   rgba(255,92,92,0.12);
  --purple:    #b07aff;
  --purple-dim:rgba(176,122,255,0.12);

  --radius:    8px;
  --radius-lg: 14px;
  --mono:      'JetBrains Mono', monospace;
  --sans:      'Bricolage Grotesque', sans-serif;
}

/* ─── RESET ─────────────────────────────────────────────────── */
*, *::before, *::after { 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;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }

/* ─── GRID BACKGROUND ────────────────────────────────────────── */
body::before {
  content: '';
  position: fixed; inset: 0; z-index: 0;
  background-image:
    linear-gradient(rgba(0,229,160,0.025) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0,229,160,0.025) 1px, transparent 1px);
  background-size: 44px 44px;
  pointer-events: none;
}

/* ─── LAYOUT ─────────────────────────────────────────────────── */
.page { position: relative; z-index: 1; }
.container { max-width: 1100px; margin: 0 auto; padding: 0 28px; }
.container-sm { max-width: 780px; margin: 0 auto; padding: 0 28px; }

/* ─── NAV ────────────────────────────────────────────────────── */
.nav {
  position: sticky; top: 0; z-index: 100;
  background: rgba(11,13,18,0.88);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
  padding: 0 28px;
  height: 60px;
  display: flex; align-items: center; gap: 0;
}
.nav-logo {
  font-family: var(--mono);
  font-size: 14px; font-weight: 700;
  color: var(--green);
  display: flex; align-items: center; gap: 8px;
  margin-right: auto;
  white-space: nowrap;
}
.nav-logo .bracket { color: var(--text3); }
.nav-links { display: flex; gap: 4px; }
.nav-link {
  font-family: var(--mono);
  font-size: 12px; color: var(--text2);
  padding: 6px 14px; border-radius: 6px;
  transition: all 0.18s;
  letter-spacing: 0.03em;
}
.nav-link:hover { color: var(--text); background: var(--bg3); }
.nav-link.active { color: var(--green); background: var(--green-dim); }

/* ─── BADGE ──────────────────────────────────────────────────── */
.badge {
  display: inline-flex; align-items: center; gap: 5px;
  font-family: var(--mono);
  font-size: 10px; font-weight: 700;
  letter-spacing: 0.08em;
  padding: 3px 9px;
  border-radius: 4px;
  text-transform: uppercase;
}
.badge-easy   { background: var(--green-dim);  color: var(--green);  border: 1px solid rgba(0,229,160,0.25); }
.badge-medium { background: var(--amber-dim);  color: var(--amber);  border: 1px solid rgba(255,181,71,0.25); }
.badge-hard   { background: var(--red-dim);    color: var(--red);    border: 1px solid rgba(255,92,92,0.25); }
.badge-module { background: var(--blue-dim);   color: var(--blue);   border: 1px solid rgba(75,142,255,0.25); }
.badge-new    { background: var(--purple-dim); color: var(--purple); border: 1px solid rgba(176,122,255,0.25); }

/* ─── CARDS ──────────────────────────────────────────────────── */
.card {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px;
  transition: border-color 0.2s;
}
.card:hover { border-color: var(--border2); }
.card-header { display: flex; align-items: flex-start; justify-content: space-between; gap: 12px; margin-bottom: 12px; }
.card-title { font-size: 16px; font-weight: 700; letter-spacing: -0.01em; }
.card-desc { font-size: 14px; color: var(--text2); line-height: 1.65; font-weight: 400; }

/* ─── TASK CARD ──────────────────────────────────────────────── */
.task-card {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: border-color 0.2s, transform 0.15s;
}
.task-card:hover { border-color: var(--border2); transform: translateY(-1px); }
.task-card.done { border-color: rgba(0,229,160,0.3); }
.task-card.done .task-card-header { background: rgba(0,229,160,0.04); }

.task-card-header {
  padding: 18px 22px;
  display: flex; align-items: center; gap: 14px;
  border-bottom: 1px solid var(--border);
  cursor: pointer;
  user-select: none;
}
.task-card-header:hover { background: rgba(255,255,255,0.02); }

.task-num {
  font-family: var(--mono);
  font-size: 11px; font-weight: 700;
  color: var(--text3);
  min-width: 28px;
}
.task-title { flex: 1; font-size: 15px; font-weight: 600; }
.task-meta { display: flex; align-items: center; gap: 8px; }
.task-chevron {
  color: var(--text3); font-size: 12px;
  transition: transform 0.2s;
}
.task-card.open .task-chevron { transform: rotate(90deg); }

.task-card-body {
  display: none;
  padding: 22px 22px 24px;
  border-top: 1px solid rgba(255,255,255,0.04);
}
.task-card.open .task-card-body { display: block; }

/* ─── CODE BLOCK ─────────────────────────────────────────────── */
.code {
  font-family: var(--mono);
  font-size: 13px;
  background: #070910;
  border: 1px solid var(--border);
  border-left: 3px solid var(--blue);
  border-radius: 6px;
  padding: 14px 18px;
  line-height: 1.8;
  overflow-x: auto;
  white-space: pre;
  color: var(--text2);
  margin: 12px 0;
}
.code .c { color: var(--text3); }
.code .cmd { color: var(--blue); }
.code .kw { color: var(--green); }
.code .str { color: var(--amber); }
.code .val { color: var(--purple); }

/* ─── ANSWER BOX ─────────────────────────────────────────────── */
.hint-btn {
  font-family: var(--mono);
  font-size: 11px; font-weight: 600;
  letter-spacing: 0.05em;
  background: transparent;
  border: 1px solid var(--border2);
  color: var(--text3);
  padding: 6px 14px;
  border-radius: 5px;
  cursor: pointer;
  transition: all 0.18s;
  margin-right: 8px;
  margin-top: 4px;
}
.hint-btn:hover { border-color: var(--amber); color: var(--amber); }
.hint-btn.open  { border-color: var(--amber); color: var(--amber); background: var(--amber-dim); }

.solution-btn {
  font-family: var(--mono);
  font-size: 11px; font-weight: 600;
  letter-spacing: 0.05em;
  background: transparent;
  border: 1px solid var(--border2);
  color: var(--text3);
  padding: 6px 14px;
  border-radius: 5px;
  cursor: pointer;
  transition: all 0.18s;
  margin-top: 4px;
}
.solution-btn:hover { border-color: var(--green); color: var(--green); }
.solution-btn.open  { border-color: var(--green); color: var(--green); background: var(--green-dim); }

.hint-box, .solution-box {
  display: none;
  margin-top: 12px;
  padding: 14px 18px;
  border-radius: 8px;
  font-size: 13px;
  line-height: 1.75;
  font-weight: 400;
}
.hint-box.show    { display: block; animation: fadeUp 0.2s ease; background: var(--amber-dim); border: 1px solid rgba(255,181,71,0.2); color: #d4b07a; }
.solution-box.show{ display: block; animation: fadeUp 0.2s ease; background: var(--green-dim);  border: 1px solid rgba(0,229,160,0.2);  color: #7acfb0; }
.hint-box code, .solution-box code {
  font-family: var(--mono); font-size: 12px;
  background: rgba(255,255,255,0.08);
  padding: 1px 5px; border-radius: 3px;
}
.hint-box strong    { color: var(--amber); font-weight: 600; }
.solution-box strong{ color: var(--green); font-weight: 600; }

/* ─── INFO / WARN BOXES ──────────────────────────────────────── */
.info-box {
  background: var(--blue-dim); border: 1px solid rgba(75,142,255,0.2);
  border-left: 3px solid var(--blue);
  border-radius: 7px; padding: 13px 17px;
  font-size: 13px; color: #8ab4e8; line-height: 1.7;
  margin: 12px 0; font-weight: 400;
}
.warn-box {
  background: var(--red-dim); border: 1px solid rgba(255,92,92,0.2);
  border-left: 3px solid var(--red);
  border-radius: 7px; padding: 13px 17px;
  font-size: 13px; color: #e89090; line-height: 1.7;
  margin: 12px 0; font-weight: 400;
}
.info-box strong { color: var(--blue); font-weight: 600; }
.warn-box strong { color: var(--red);  font-weight: 600; }

/* ─── STEPS ──────────────────────────────────────────────────── */
.steps { list-style: none; counter-reset: step; margin: 12px 0; }
.steps li {
  counter-increment: step;
  padding: 9px 0 9px 36px;
  position: relative;
  font-size: 14px; line-height: 1.65; color: var(--text2);
  border-bottom: 1px solid rgba(255,255,255,0.04);
  font-weight: 400;
}
.steps li:last-child { border-bottom: none; }
.steps li::before {
  content: counter(step);
  position: absolute; left: 0; top: 11px;
  font-family: var(--mono); font-size: 10px; font-weight: 700;
  width: 20px; height: 20px; border-radius: 4px;
  display: flex; align-items: center; justify-content: center;
  background: var(--blue-dim); border: 1px solid rgba(75,142,255,0.25); color: var(--blue);
}

/* ─── TABLE ──────────────────────────────────────────────────── */
.data-table { width: 100%; border-collapse: collapse; font-size: 13px; margin: 12px 0; }
.data-table th {
  font-family: var(--mono); font-size: 10px; font-weight: 700;
  letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--text3); text-align: left;
  padding: 9px 14px; border-bottom: 1px solid var(--border);
}
.data-table td {
  padding: 10px 14px; color: var(--text2);
  border-bottom: 1px solid rgba(255,255,255,0.04);
  vertical-align: top; line-height: 1.5;
}
.data-table tr:last-child td { border-bottom: none; }
.data-table td:first-child { font-family: var(--mono); color: var(--blue); font-size: 12px; white-space: nowrap; }
.data-table td code { font-family: var(--mono); font-size: 11px; background: rgba(255,255,255,0.06); padding: 1px 5px; border-radius: 3px; }

/* ─── BUTTONS ────────────────────────────────────────────────── */
.btn {
  display: inline-flex; align-items: center; gap: 7px;
  font-family: var(--mono); font-size: 12px; font-weight: 700;
  letter-spacing: 0.04em; padding: 9px 20px;
  border-radius: 7px; border: none; cursor: pointer;
  transition: all 0.18s; text-decoration: none;
}
.btn-primary { background: var(--blue);  color: #fff; }
.btn-primary:hover { background: #6fa3ff; }
.btn-success { background: var(--green); color: #0b0d12; }
.btn-success:hover { background: #33ffb3; }
.btn-danger  { background: var(--red);   color: #fff; }
.btn-danger:hover  { background: #ff8585; }
.btn-ghost { background: transparent; color: var(--text2); border: 1px solid var(--border2); }
.btn-ghost:hover { border-color: var(--text2); color: var(--text); }

/* ─── TERMINAL ───────────────────────────────────────────────── */
.terminal {
  background: #05070a;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden; font-family: var(--mono);
}
.terminal-bar {
  background: var(--bg3); padding: 10px 16px;
  display: flex; align-items: center; gap: 7px;
  border-bottom: 1px solid var(--border);
}
.terminal-bar .dot { width: 11px; height: 11px; border-radius: 50%; }
.dot-r { background: #ff5f57; } .dot-y { background: #febc2e; } .dot-g { background: #28c840; }
.terminal-bar .title { font-size: 11px; color: var(--text3); margin-left: 6px; }
.terminal-body {
  padding: 16px 18px; min-height: 100px;
  max-height: 300px; overflow-y: auto;
  font-size: 13px; line-height: 1.9;
}
.tl-prompt { color: var(--green); }
.tl-out    { color: var(--text2); }
.tl-info   { color: var(--amber); }
.tl-err    { color: var(--red); }
.terminal-input-row {
  display: flex; align-items: center;
  padding: 10px 18px;
  border-top: 1px solid var(--border);
  background: #05070a;
}
.term-ps1 { color: var(--green); font-size: 13px; white-space: nowrap; margin-right: 6px; }
.term-in  {
  flex: 1; background: transparent; border: none; outline: none;
  color: var(--text); font-family: var(--mono); font-size: 13px;
  caret-color: var(--green);
}

/* ─── INTERACTIVE LABS ───────────────────────────────────────── */
.lab-frame {
  background: #06080c;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden; margin: 14px 0;
}
.lab-topbar {
  background: var(--bg3); padding: 9px 16px;
  display: flex; align-items: center; gap: 7px;
  border-bottom: 1px solid var(--border);
  font-family: var(--mono); font-size: 11px; color: var(--text3);
}
.lab-body { padding: 20px; }
.lab-body label { display: block; font-family: var(--mono); font-size: 11px; color: var(--text3); margin-bottom: 6px; letter-spacing: 0.06em; }
.lab-body input[type=text], .lab-body textarea {
  width: 100%; background: var(--bg3); border: 1px solid var(--border);
  color: var(--text); padding: 10px 13px; border-radius: 7px;
  font-family: var(--mono); font-size: 13px; outline: none;
  transition: border-color 0.18s; margin-bottom: 10px;
}
.lab-body input:focus, .lab-body textarea:focus { border-color: var(--blue); }
.lab-output {
  background: var(--bg3); border: 1px solid var(--border);
  border-radius: 7px; padding: 12px 15px; min-height: 44px;
  font-size: 14px; margin-top: 12px;
}
.lab-output-label { font-family: var(--mono); font-size: 10px; color: var(--text3); margin-bottom: 5px; letter-spacing: 0.08em; text-transform: uppercase; }
.status { display: none; margin-top: 10px; padding: 9px 13px; border-radius: 6px; font-family: var(--mono); font-size: 12px; }
.status.danger { display: block; background: var(--red-dim);   border: 1px solid rgba(255,92,92,0.25);  color: var(--red); }
.status.safe   { display: block; background: var(--green-dim); border: 1px solid rgba(0,229,160,0.25); color: var(--green); }
.status.info   { display: block; background: var(--blue-dim);  border: 1px solid rgba(75,142,255,0.25); color: var(--blue); }

/* ─── HASH OUTPUT ────────────────────────────────────────────── */
.hash-out {
  font-family: var(--mono); font-size: 12px; word-break: break-all;
  color: var(--green); background: var(--green-dim);
  border: 1px solid rgba(0,229,160,0.2);
  padding: 11px 14px; border-radius: 7px;
  margin-top: 10px; min-height: 42px; display: flex; align-items: center;
}

/* ─── QUIZ ───────────────────────────────────────────────────── */
.quiz-opt {
  display: flex; align-items: flex-start; gap: 11px;
  padding: 11px 15px; border: 1px solid var(--border);
  border-radius: 7px; margin-bottom: 8px;
  cursor: pointer; transition: all 0.18s;
  font-size: 14px; color: var(--text2); font-weight: 400;
}
.quiz-opt:hover { border-color: var(--blue); color: var(--text); background: var(--blue-dim); }
.quiz-opt.correct { border-color: var(--green); background: var(--green-dim); color: var(--green); pointer-events: none; }
.quiz-opt.wrong   { border-color: var(--red);   background: var(--red-dim);   color: var(--red);   pointer-events: none; }
.quiz-opt.reveal  { border-color: var(--green); background: var(--green-dim); color: var(--green); pointer-events: none; opacity: 0.7; }
.quiz-opt .lbl { font-family: var(--mono); font-size: 11px; font-weight: 700; min-width: 18px; margin-top: 2px; }

/* ─── PROGRESS BAR ───────────────────────────────────────────── */
.progress-wrap { margin-bottom: 10px; }
.progress-label { font-family: var(--mono); font-size: 11px; color: var(--text3); margin-bottom: 6px; display: flex; justify-content: space-between; }
.progress-track { height: 4px; background: var(--bg4); border-radius: 2px; overflow: hidden; }
.progress-fill  { height: 100%; background: var(--green); border-radius: 2px; transition: width 0.4s ease; }

/* ─── FILTER PILLS ───────────────────────────────────────────── */
.filter-row { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 24px; }
.filter-pill {
  font-family: var(--mono); font-size: 11px; font-weight: 600;
  letter-spacing: 0.05em; padding: 6px 15px;
  border-radius: 20px; border: 1px solid var(--border2);
  background: transparent; color: var(--text2);
  cursor: pointer; transition: all 0.18s;
}
.filter-pill:hover { border-color: var(--text2); color: var(--text); }
.filter-pill.active-all    { background: var(--bg3); border-color: var(--text2); color: var(--text); }
.filter-pill.active-easy   { background: var(--green-dim); border-color: rgba(0,229,160,0.4); color: var(--green); }
.filter-pill.active-medium { background: var(--amber-dim); border-color: rgba(255,181,71,0.4); color: var(--amber); }
.filter-pill.active-hard   { background: var(--red-dim);   border-color: rgba(255,92,92,0.4);  color: var(--red); }

/* ─── SECTION HEADER ─────────────────────────────────────────── */
.section-eyebrow {
  font-family: var(--mono); font-size: 11px; font-weight: 700;
  letter-spacing: 0.12em; text-transform: uppercase;
  color: var(--text3); margin-bottom: 8px;
}
.section-title {
  font-size: clamp(22px, 3.5vw, 32px); font-weight: 800;
  letter-spacing: -0.02em; line-height: 1.15;
}
.section-title span { color: var(--green); }
.section-desc { font-size: 15px; color: var(--text2); margin-top: 10px; line-height: 1.65; font-weight: 400; max-width: 620px; }

/* ─── DIVIDER ────────────────────────────────────────────────── */
hr.div { border: none; border-top: 1px solid var(--border); margin: 28px 0; }

/* ─── ANIMATIONS ─────────────────────────────────────────────── */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(10px); }
  to   { opacity: 1; transform: translateY(0); }
}
.fade-up { animation: fadeUp 0.35s ease both; }

/* ─── FOOTER ─────────────────────────────────────────────────── */
.footer {
  border-top: 1px solid var(--border); padding: 28px 0;
  margin-top: 80px;
}
.footer-inner {
  display: flex; align-items: center; justify-content: space-between;
  font-family: var(--mono); font-size: 11px; color: var(--text3);
  flex-wrap: wrap; gap: 10px;
}
.footer-inner a { color: var(--text3); transition: color 0.2s; }
.footer-inner a:hover { color: var(--green); }

/* ─── RESPONSIVE ─────────────────────────────────────────────── */
@media (max-width: 640px) {
  .container, .container-sm { padding: 0 16px; }
  .nav { padding: 0 16px; }
  .nav-links .nav-link { padding: 6px 9px; font-size: 11px; }
}