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

:root {
  --bg:     #07070f;
  --card:   #0f0f1c;
  --border: #1e1e35;
  --text:   #e2e8f0;
  --muted:  #64748b;
  --dim:    #2d3748;
  --code:   #0d1117;
  
  /* Warna aksen per topik */
  --blue:   #60a5fa;
  --purple: #a78bfa;
  --yellow: #fbbf24;
  --cyan:   #22d3ee;
  --indigo: #818cf8;
  --gray:   #94a3b8;
  --green:  #4ade80;
  
  /* Glow */
  --gblue:  rgba(96,165,250,.12);
  --gpurp:  rgba(167,139,250,.12);
  --gyellow: rgba(251,191,36,.12);
  --gcyan:  rgba(34,211,238,.12);
  --gindigo: rgba(129,140,248,.12);
  --ggray:  rgba(148,163,184,.12);
}

*, *::before, *::after { margin:0; padding:0; box-sizing:border-box; }
html { scroll-behavior:smooth; }

body {
  background:var(--bg);
  color:var(--text);
  font-family:'Space Grotesk',sans-serif;
  min-height:100vh;
  overflow-x:hidden;
}

::-webkit-scrollbar { width:5px; }
::-webkit-scrollbar-track { background:var(--bg); }
::-webkit-scrollbar-thumb { background:var(--border); border-radius:3px; }

/* ── NAV ── */
nav {
  position:sticky; top:0; z-index:200;
  background:rgba(7,7,15,.88);
  backdrop-filter:blur(16px);
  border-bottom:1px solid var(--border);
  padding:.85rem 2rem;
  display:flex; align-items:center; justify-content:space-between; gap:1.2rem;
}
.logo {
  font-size:1rem; font-weight:700;
  background:linear-gradient(135deg,var(--blue),var(--purple));
  -webkit-background-clip:text; -webkit-text-fill-color:transparent;
  text-decoration:none; letter-spacing:-.5px; white-space:nowrap;
}
.nav-links { display:flex; gap:1.2rem; list-style:none; }
.nav-links a {
  color:var(--muted); text-decoration:none;
  font-size:.85rem; font-weight:500; transition:color .2s;
}
.nav-links a:hover, .nav-links a.active { color:var(--text); }

/* ── SEARCH ── */
.search-wrap { position:relative; width:100%; max-width:340px; }
.search-ico {
  position:absolute; left:.75rem; top:50%; transform:translateY(-50%);
  color:var(--muted); pointer-events:none; display:flex;
}
.search-input {
  width:100%;
  background:var(--card); border:1px solid var(--border);
  color:var(--text); padding:.58rem .9rem .58rem 2.3rem;
  font-family:'Space Grotesk',sans-serif; font-size:.85rem;
  border-radius:8px; outline:none; transition:border-color .2s;
}
.search-input:focus { border-color:var(--blue); }
.search-input::placeholder { color:var(--muted); }

/* ── CONTAINER ── */
.container { max-width:1100px; margin:0 auto; padding:2rem 1.5rem; }

/* ── HERO ── */
.hero { text-align:center; padding:5rem 1.5rem 3.5rem; }
.badge {
  display:inline-flex; align-items:center; gap:.4rem;
  background:var(--gpurp); border:1px solid rgba(167,139,250,.3);
  color:var(--purple); font-size:.7rem; font-weight:700;
  letter-spacing:2px; text-transform:uppercase;
  padding:.32rem 1rem; border-radius:100px; margin-bottom:1.5rem;
}
.hero h1 {
  font-size:clamp(2.2rem,6vw,4rem);
  font-weight:700; letter-spacing:-1.5px;
  line-height:1.1; margin-bottom:1rem;
}
.grad {
  background:linear-gradient(135deg,var(--blue) 30%,var(--purple));
  -webkit-background-clip:text; -webkit-text-fill-color:transparent;
}
.hero p {
  color:var(--muted); font-size:.95rem;
  max-width:400px; margin:0 auto 2.5rem; line-height:1.75;
}

/* ── SECTION LABEL ── */
.sec-label {
  font-size:.7rem; font-weight:700; letter-spacing:2.5px;
  text-transform:uppercase; color:var(--muted); margin-bottom:1.2rem;
}

/* ── TOPIC CARDS UPGRADE ── */
.topics-grid {
  display:grid;
  grid-template-columns:repeat(auto-fill,minmax(260px,1fr));
  gap:1.2rem;
}
.topic-card {
  background:var(--card); border:1px solid var(--border);
  padding:1.6rem; border-radius:14px; text-decoration:none;
  display:flex; flex-direction:column; gap:.75rem;
  transition:transform .25s, border-color .25s, box-shadow .25s;
  position:relative; overflow:hidden;
}
.topic-card::before {
  content:''; position:absolute; top:0; left:0; right:0;
  height:3px; background:currentColor; opacity:.8;
}
.topic-card::after {
  content:''; position:absolute; inset:0;
  opacity:0; transition:opacity .3s; z-index:0;
}
.topic-card > * { position:relative; z-index:1; }

.topic-card:hover { transform:translateY(-4px); }
.topic-card:hover::after { opacity:1; }

.topic-card.blue   { color:var(--blue); }
.topic-card.blue::after   { background:var(--gblue); }
.topic-card.blue:hover    { border-color:rgba(96,165,250,.45); box-shadow:0 8px 30px rgba(96,165,250,.1); }

.topic-card.purple { color:var(--purple); }
.topic-card.purple::after { background:var(--gpurp); }
.topic-card.purple:hover  { border-color:rgba(167,139,250,.45); box-shadow:0 8px 30px rgba(167,139,250,.1); }

.topic-card.yellow { color:var(--yellow); }
.topic-card.yellow::after { background:var(--gyellow); }
.topic-card.yellow:hover  { border-color:rgba(251,191,36,.45); box-shadow:0 8px 30px rgba(251,191,36,.1); }

.topic-card.cyan   { color:var(--cyan); }
.topic-card.cyan::after   { background:var(--gcyan); }
.topic-card.cyan:hover    { border-color:rgba(34,211,238,.45); box-shadow:0 8px 30px rgba(34,211,238,.1); }

.topic-card.indigo { color:var(--indigo); }
.topic-card.indigo::after { background:var(--gindigo); }
.topic-card.indigo:hover  { border-color:rgba(129,140,248,.45); box-shadow:0 8px 30px rgba(129,140,248,.1); }

.topic-card.gray   { color:var(--gray); }
.topic-card.gray::after   { background:var(--ggray); }
.topic-card.gray:hover    { border-color:rgba(148,163,184,.45); box-shadow:0 8px 30px rgba(148,163,184,.1); }

.topic-icon {
  width:52px; height:52px; border-radius:12px;
  display:grid; place-items:center;
  background: rgba(255,255,255,.04);
  border:1px solid var(--border);
  margin-bottom:.3rem;
}
.topic-icon svg {
  stroke: currentColor;
  width:26px; height:26px;
}
.topic-name  { font-size:1.15rem; font-weight:700; letter-spacing:-.4px; color:var(--text); }
.topic-desc  { font-size:.85rem; color:var(--muted); line-height:1.65; }
.topic-meta  {
  font-size:.72rem; color:var(--dim);
  padding-top:.8rem; margin-top:auto;
  border-top:1px solid var(--border);
}

/* ── LEARNING LAYOUT ── */
.learn-wrap {
  display:grid;
  grid-template-columns:210px 1fr;
  gap:2rem;
  max-width:1100px; margin:0 auto;
  padding:2rem 1.5rem;
  align-items:start;
}

.sidebar {
  position:sticky; top:72px;
  background:var(--card); border:1px solid var(--border);
  border-radius:12px; padding:1rem;
}
.sidebar-head {
  font-size:.65rem; font-weight:700; letter-spacing:2px;
  text-transform:uppercase; color:var(--muted);
  padding-bottom:.7rem; margin-bottom:.5rem;
  border-bottom:1px solid var(--border);
}
.sb-link {
  display:block; padding:.5rem .75rem; border-radius:7px;
  color:var(--muted); text-decoration:none;
  font-size:.82rem; font-weight:500;
  transition:all .18s; margin-bottom:.15rem;
}
.sb-link:hover { color:var(--text); background:var(--border); }
.sb-link.on    { color:var(--blue); background:var(--gblue); }

.learn-main { min-width:0; }
.page-head {
  margin-bottom:2.5rem;
  padding-bottom:1.5rem;
  border-bottom:1px solid var(--border);
}
.breadcrumb { font-size:.73rem; color:var(--dim); margin-bottom:.6rem; }
.breadcrumb a { color:var(--muted); text-decoration:none; }
.breadcrumb a:hover { color:var(--text); }
.page-head h1 { font-size:1.85rem; font-weight:700; letter-spacing:-.8px; margin-bottom:.4rem; }
.page-head p  { color:var(--muted); font-size:.9rem; line-height:1.6; }

.sec { margin-bottom:2.8rem; scroll-margin-top:82px; }
.sec.hidden { display:none; }
.sec h2 { font-size:1.2rem; font-weight:700; letter-spacing:-.4px; margin-bottom:.6rem; }
.sec p  { color:var(--muted); line-height:1.8; font-size:.9rem; margin-bottom:.9rem; }
.sec ul, .sec ol { color:var(--muted); font-size:.88rem; line-height:2; padding-left:1.3rem; margin-bottom:1rem; }

.tag-il {
  font-family:'JetBrains Mono',monospace; font-size:.78rem;
  background:var(--gblue); border:1px solid rgba(96,165,250,.25);
  color:var(--blue); padding:.05rem .4rem; border-radius:4px;
}
.note {
  background:rgba(96,165,250,.06);
  border-left:3px solid var(--blue);
  padding:.8rem 1rem; border-radius:0 8px 8px 0;
  font-size:.85rem; color:var(--muted); line-height:1.6;
  margin-bottom:1rem;
}

/* CODE BOX */
.code-box {
  background:var(--code); border:1px solid var(--border);
  border-radius:10px; overflow:hidden; margin:.8rem 0;
}
.code-top {
  display:flex; align-items:center; justify-content:space-between;
  padding:.5rem 1rem; background:#0a0e15;
  border-bottom:1px solid var(--border);
}
.code-lang { font-size:.65rem; font-weight:700; letter-spacing:1.5px; text-transform:uppercase; color:var(--muted); }
.copy-btn {
  background:transparent; border:1px solid var(--border);
  color:var(--muted); font-size:.68rem; padding:.2rem .6rem;
  border-radius:5px; cursor:pointer;
  font-family:'Space Grotesk',sans-serif; transition:all .2s;
}
.copy-btn:hover { color:var(--text); border-color:var(--blue); }
.copy-btn.ok    { color:var(--green); border-color:var(--green); }
pre { padding:1.1rem 1.2rem; overflow-x:auto; }
pre code.hljs {
  background:transparent !important;
  padding:0 !important;
  font-family:'JetBrains Mono',monospace !important;
  font-size:.8rem !important;
  line-height:1.8 !important;
}

/* LIVE EDITOR */
.editor {
  background:var(--card); border:1px solid var(--border);
  border-radius:12px; overflow:hidden; margin-top:.5rem;
}
.editor-top {
  display:flex; align-items:center; justify-content:space-between;
  padding:.65rem 1rem; background:#0a0e15;
  border-bottom:1px solid var(--border);
}
.editor-lbl { font-size:.72rem; font-weight:600; color:var(--muted); }
.run-btn {
  background:linear-gradient(135deg,var(--blue),var(--purple));
  border:none; color:#fff; font-size:.75rem; font-weight:700;
  padding:.36rem 1.1rem; border-radius:6px; cursor:pointer;
  font-family:'Space Grotesk',sans-serif; transition:opacity .2s;
}
.run-btn:hover { opacity:.85; }
.editor-panes { display:grid; grid-template-columns:1fr 1fr; }
.pane-lbl {
  font-size:.62rem; font-weight:700; letter-spacing:1.5px;
  text-transform:uppercase; color:var(--dim);
  padding:.42rem 1rem; border-bottom:1px solid var(--border);
  background:var(--code);
}
.left-pane .pane-lbl { border-right:1px solid var(--border); }
textarea.ted {
  background:var(--code); border:none;
  border-right:1px solid var(--border);
  color:#cdd9e5; font-family:'JetBrains Mono',monospace;
  font-size:.78rem; line-height:1.7;
  padding:1rem; resize:none; height:480px;
  outline:none; tab-size:2; width:100%;
}
iframe.prev { background:#fff; border:none; width:100%; height:480px; }
.console-out {
  background:var(--code);
  font-family:'JetBrains Mono',monospace; font-size:.78rem;
  padding:1rem; height:480px; overflow-y:auto; white-space:pre-wrap;
}
.c-log  { color:#cdd9e5; }
.c-info { color:#60a5fa; }
.c-warn { color:#fbbf24; }
.c-err  { color:#f87171; }

hr.divider { border:none; border-top:1px solid var(--border); margin:2rem 0; }

/* RESPONSIVE */
@media (max-width:768px) {
  .learn-wrap { grid-template-columns:1fr; }
  .sidebar    { position:static; }
  .editor-panes { grid-template-columns:1fr; }
  textarea.ted  { border-right:none; border-bottom:1px solid var(--border); }
  nav { padding:.7rem 1rem; }
  .nav-links { display:none; }
  .search-wrap { max-width:100%; }
}

.topic-card.purple { border-color: #9333ea; }
.topic-card.purple .topic-icon { background: #9333ea20; color: #9333ea; }
.topic-card.indigo { border-color: #4f46e5; }
.topic-card.indigo .topic-icon { background: #4f46e520; color: #4f46e5; }
.topic-card.cyan { border-color: #06b6d4; }
.topic-card.cyan .topic-icon { background: #06b6d420; color: #06b6d4; }
.topic-card.pink { border-color: #ec4899; }
.topic-card.pink .topic-icon { background: #ec489920; color: #ec4899; }
.topic-card.teal { border-color: #14b8a6; }
.topic-card.teal .topic-icon { background: #14b8a620; color: #14b8a6; }
.topic-card.sky { border-color: #0ea5e9; }
.topic-card.sky .topic-icon { background: #0ea5e920; color: #0ea5e9; }
.topic-card.violet { border-color: #8b5cf6; }
.topic-card.violet .topic-icon { background: #8b5cf620; color: #8b5cf6; }
.topic-card.emerald { border-color: #10b981; }
.topic-card.emerald .topic-icon { background: #10b98120; color: #10b981; }
.topic-card.fuchsia { border-color: #d946ef; }
.topic-card.fuchsia .topic-icon { background: #d946ef20; color: #d946ef; }
.topic-card.amber { border-color: #f59e0b; }
.topic-card.amber .topic-icon { background: #f59e0b20; color: #f59e0b; }
.topic-card.slate { border-color: #64748b; }
.topic-card.slate .topic-icon { background: #64748b20; color: #64748b; }
.topic-card.lime { border-color: #84cc16; }
.topic-card.lime .topic-icon { background: #84cc1620; color: #84cc16; }


/* ════════════════════════════════════════════════
   TAMBAHAN UNTUK UPGRADE HALAMAN BELAJAR HTML
   (hamburger, theme toggle, best-practice, tabs, sec-nav)
   ════════════════════════════════════════════════ */

/* --- Hamburger menu (mobile only) --- */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 4px;
  width: 32px;
  height: 32px;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: 4px;
}
.hamburger span {
  display: block;
  width: 100%;
  height: 2px;
  background: currentColor;
  border-radius: 2px;
  transition: transform .25s ease, opacity .25s ease;
}
.hamburger.active span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.hamburger.active span:nth-child(2) { opacity: 0; }
.hamburger.active span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,.5);
  z-index: 40;
}
.sidebar-overlay.show { display: block; }

/* --- Theme toggle button --- */
.theme-toggle {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 999px;
  width: 34px;
  height: 34px;
  font-size: 15px;
  cursor: pointer;
  opacity: .85;
  margin-left: 8px;
  flex-shrink: 0;
}
.theme-toggle:hover { opacity: 1; border-color: var(--blue); }

/* --- Light mode override (asumsi default tema gelap) --- */
body.light-mode {
  background: #f6f7fb !important;
  color: #1b1b2a !important;
}
body.light-mode nav,
body.light-mode .sidebar,
body.light-mode .sec,
body.light-mode .editor,
body.light-mode .note,
body.light-mode .best-practice,
body.light-mode .code-box,
body.light-mode .topic-card {
  background: #ffffff !important;
  color: #1b1b2a !important;
  border-color: #e3e3ee !important;
}
body.light-mode .sec p,
body.light-mode .sec ul,
body.light-mode .sec ol,
body.light-mode .page-head p { color: #5a5a72 !important; }
body.light-mode .tag-il {
  background: #eef0ff !important;
  color: #4338ca !important;
}
body.light-mode .sb-link { color: #3a3a55 !important; }
body.light-mode .sb-link.on,
body.light-mode .sb-link:hover { color: #6366f1 !important; background:#eef0ff !important; }
body.light-mode .search-input {
  background: #f1f1f7 !important;
  color: #1b1b2a !important;
}
body.light-mode .ted,
body.light-mode .code-top,
body.light-mode .editor-top,
body.light-mode .pane-lbl {
  background: #f8f8fc !important;
  color: #1b1b2a !important;
}

/* --- Best practice box --- */
.best-practice {
  margin: 16px 0;
  padding: 12px 16px;
  border-left: 3px solid var(--green);
  background: rgba(74,222,128,.08);
  border-radius: 0 8px 8px 0;
  font-size: .85rem;
  line-height: 1.7;
  color: var(--muted);
}
.best-practice a { color: var(--blue); }

/* --- Editor tabs --- */
.editor-tabs {
  display: flex;
  gap: 4px;
  padding: .5rem .5rem 0;
  background: #0a0e15;
  border-bottom: 1px solid var(--border);
}
.tab-btn {
  background: transparent;
  border: none;
  border-bottom: 2px solid transparent;
  color: var(--muted);
  padding: .5rem 1rem;
  font-size: .78rem;
  font-weight: 600;
  cursor: pointer;
  font-family: 'Space Grotesk', sans-serif;
  border-radius: 6px 6px 0 0;
}
.tab-btn.active {
  color: var(--text);
  border-bottom: 2px solid var(--blue);
}
.ted.hidden { display: none; }

/* --- Previous / Next navigation --- */
.sec-nav {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  margin-top: 1.6rem;
  padding-top: 1rem;
}
.sec-nav-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: .65rem 1rem;
  border-radius: 10px;
  border: 1px solid var(--border);
  text-decoration: none;
  color: var(--muted);
  font-size: .78rem;
  max-width: 48%;
  transition: background .2s ease, border-color .2s ease, color .2s ease;
}
.sec-nav-btn:hover {
  border-color: var(--blue);
  background: var(--gblue);
  color: var(--text);
}
.sec-nav-btn.next { margin-left: auto; text-align: right; flex-direction: row-reverse; }
.sec-nav-btn span { font-weight: 700; color: var(--text); }

/* --- Responsiveness tambahan --- */
@media (max-width: 900px) {
  .hamburger { display: flex; }
  .sidebar {
    position: fixed !important;
    top: 0;
    left: 0;
    height: 100vh;
    width: 240px;
    transform: translateX(-105%);
    transition: transform .25s ease;
    z-index: 50;
    overflow-y: auto;
    border-radius: 0;
  }
  .sidebar.open { transform: translateX(0); }
  textarea.ted, iframe.prev { height: 360px; }
}

@media (max-width: 600px) {
  textarea.ted, iframe.prev { height: 300px; }
  .sec-nav-btn { max-width: 100%; }
  .sec-nav { flex-direction: column; }
  .sec-nav-btn.next { margin-left: 0; flex-direction: row; text-align: left; }
}