/* ============================================================
   INFORMATIKA IX — LMS ROADMAP
   style.css — Design tokens, base styles, layout shell
   ============================================================ */

/* ---------- Design tokens ---------- */
:root{
  /* Core surfaces */
  --bg-deep:        #0a0e1a;
  --bg-deep-2:      #0d1220;
  --bg-surface:     #121829;
  --bg-surface-2:   #161d33;
  --glass:          rgba(255,255,255,0.055);
  --glass-strong:   rgba(255,255,255,0.09);
  --glass-border:   rgba(255,255,255,0.10);
  --glass-border-hi:rgba(255,255,255,0.18);

  /* Accents — indigo/violet + circuit cyan, amber for signal */
  --accent-1:       #6C5CE7;   /* violet-indigo, primary */
  --accent-1-soft:  #8B7CF6;
  --accent-2:       #00D9C0;   /* circuit cyan */
  --accent-2-soft:  #5EEBDA;
  --accent-warn:    #FFB454;   /* amber — difficulty / signal */
  --accent-danger:  #FF6B6B;

  /* Text */
  --text-hi:        #F3F5FB;
  --text-mid:       #C7CCDD;
  --text-muted:     #8992AB;
  --text-faint:     #5A6280;

  /* Gradients */
  --grad-primary:   linear-gradient(135deg, #6C5CE7 0%, #00B4D8 100%);
  --grad-ganjil:    linear-gradient(135deg, #6C5CE7 0%, #A78BFA 100%);
  --grad-genap:     linear-gradient(135deg, #00B4D8 0%, #00D9C0 100%);
  --grad-mesh:      radial-gradient(circle at 20% 20%, rgba(108,92,231,0.35), transparent 45%),
                     radial-gradient(circle at 80% 0%, rgba(0,217,192,0.22), transparent 40%),
                     radial-gradient(circle at 50% 100%, rgba(108,92,231,0.18), transparent 50%);

  /* Radii & shadow */
  --r-sm: 10px;
  --r-md: 16px;
  --r-lg: 24px;
  --r-xl: 32px;
  --shadow-soft: 0 8px 30px rgba(0,0,0,0.35);
  --shadow-glow: 0 0 0 1px rgba(108,92,231,0.25), 0 12px 40px rgba(108,92,231,0.18);

  /* Type */
  --font-display: 'Poppins', sans-serif;
  --font-body: 'Poppins', sans-serif;
  --font-mono: 'Space Mono', 'Consolas', monospace;

  --nav-h: 76px;
  --transition: 0.35s cubic-bezier(.22,.9,.32,1);
}

/* ---------- Light mode override ---------- */
body.light-mode{
  --bg-deep:        #F5F6FB;
  --bg-deep-2:      #EFF1F9;
  --bg-surface:     #FFFFFF;
  --bg-surface-2:   #F7F8FD;
  --glass:          rgba(20,20,40,0.04);
  --glass-strong:   rgba(20,20,40,0.06);
  --glass-border:   rgba(20,20,40,0.08);
  --glass-border-hi:rgba(20,20,40,0.14);
  --text-hi:        #171A2B;
  --text-mid:       #3C425C;
  --text-muted:     #6B7290;
  --text-faint:     #9BA0BD;
  --shadow-soft: 0 8px 30px rgba(30,30,60,0.10);
}

/* ---------- Reset ---------- */
*,*::before,*::after{ box-sizing:border-box; margin:0; padding:0; }
html{ scroll-behavior:smooth; }
body{
  font-family:var(--font-body);
  background:var(--bg-deep);
  color:var(--text-mid);
  line-height:1.65;
  overflow-x:hidden;
  transition:background var(--transition), color var(--transition);
}
img{ max-width:100%; display:block; }
a{ color:inherit; text-decoration:none; }
ul{ list-style:none; }
button{ font-family:inherit; cursor:pointer; border:none; background:none; color:inherit; }
h1,h2,h3,h4{ font-family:var(--font-display); color:var(--text-hi); font-weight:700; letter-spacing:-0.01em; }

::selection{ background:var(--accent-1); color:#fff; }

/* Focus visibility (a11y) */
a:focus-visible, button:focus-visible, [tabindex]:focus-visible{
  outline:2px solid var(--accent-2);
  outline-offset:3px;
  border-radius:6px;
}

@media (prefers-reduced-motion: reduce){
  *{ animation-duration:0.001ms !important; animation-iteration-count:1 !important; transition-duration:0.001ms !important; scroll-behavior:auto !important; }
}

/* ---------- Background mesh (fixed, behind everything) ---------- */
.bg-mesh{
  position:fixed; inset:0; z-index:-2;
  background:var(--bg-deep);
  background-image:var(--grad-mesh);
}
.bg-noise{
  position:fixed; inset:0; z-index:-1; pointer-events:none;
  opacity:0.03;
  background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='120' height='120'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

/* ---------- Loading screen ---------- */
#loading-screen{
  position:fixed; inset:0; z-index:9999;
  display:flex; flex-direction:column; align-items:center; justify-content:center; gap:18px;
  background:var(--bg-deep);
  transition:opacity 0.6s ease, visibility 0.6s ease;
}
#loading-screen.hidden{ opacity:0; visibility:hidden; pointer-events:none; }
.loader-node{
  width:64px; height:64px; position:relative;
}
.loader-node svg{ width:100%; height:100%; }
.loader-node circle{
  fill:none; stroke:var(--accent-2); stroke-width:4; stroke-linecap:round;
  stroke-dasharray:180; stroke-dashoffset:180;
  animation:loaderRing 1.4s ease-in-out infinite;
  transform-origin:center;
}
@keyframes loaderRing{
  0%{ stroke-dashoffset:180; transform:rotate(0deg); }
  50%{ stroke-dashoffset:40; transform:rotate(180deg); }
  100%{ stroke-dashoffset:180; transform:rotate(360deg); }
}
.loader-text{ font-family:var(--font-mono); font-size:13px; letter-spacing:.12em; color:var(--text-muted); text-transform:uppercase; }

/* ---------- Navbar ---------- */
.navbar{
  position:fixed; top:0; left:0; right:0; z-index:1000;
  height:var(--nav-h);
  display:flex; align-items:center;
  padding:0 clamp(20px,4vw,56px);
  background:rgba(10,14,26,0.55);
  backdrop-filter:blur(18px) saturate(140%);
  -webkit-backdrop-filter:blur(18px) saturate(140%);
  border-bottom:1px solid var(--glass-border);
  transition:background var(--transition), border-color var(--transition), padding var(--transition);
}
body.light-mode .navbar{ background:rgba(255,255,255,0.65); }
.navbar.scrolled{ height:64px; box-shadow:var(--shadow-soft); }

.nav-inner{
  width:100%; max-width:1400px; margin:0 auto;
  display:flex; align-items:center; justify-content:space-between; gap:24px;
}
.brand{ display:flex; align-items:center; gap:10px; font-family:var(--font-display); font-weight:700; font-size:17px; color:var(--text-hi); }
.brand .brand-badge{
  width:36px; height:36px; border-radius:10px;
  background:var(--grad-primary);
  display:flex; align-items:center; justify-content:center;
  color:#fff; font-size:16px; box-shadow:var(--shadow-glow);
}
.nav-links{ display:flex; align-items:center; gap:30px; }
.nav-links a{
  font-size:14.5px; font-weight:500; color:var(--text-mid);
  position:relative; padding:6px 0;
  transition:color var(--transition);
}
.nav-links a::after{
  content:''; position:absolute; left:0; bottom:0; height:2px; width:0;
  background:var(--grad-primary); transition:width var(--transition);
}
.nav-links a:hover{ color:var(--text-hi); }
.nav-links a:hover::after{ width:100%; }

.nav-actions{ display:flex; align-items:center; gap:14px; }
.icon-btn{
  width:40px; height:40px; border-radius:12px;
  display:flex; align-items:center; justify-content:center;
  background:var(--glass); border:1px solid var(--glass-border);
  color:var(--text-mid); font-size:15px;
  transition:all var(--transition);
}
.icon-btn:hover{ background:var(--glass-strong); color:var(--text-hi); transform:translateY(-2px); }

.nav-toggle{
  display:none; width:40px; height:40px; border-radius:12px;
  align-items:center; justify-content:center; font-size:18px;
  background:var(--glass); border:1px solid var(--glass-border); color:var(--text-hi);
}

/* ---------- Buttons ---------- */
.btn{
  display:inline-flex; align-items:center; gap:10px;
  padding:14px 28px; border-radius:100px;
  font-weight:600; font-size:15px; letter-spacing:0.01em;
  transition:transform var(--transition), box-shadow var(--transition), background var(--transition);
}
.btn-primary{
  background:var(--grad-primary); color:#fff;
  box-shadow:0 10px 30px rgba(108,92,231,0.35);
}
.btn-primary:hover{ transform:translateY(-3px); box-shadow:0 16px 40px rgba(108,92,231,0.45); }
.btn-ghost{
  background:var(--glass); border:1px solid var(--glass-border); color:var(--text-hi);
}
.btn-ghost:hover{ background:var(--glass-strong); transform:translateY(-3px); }

.btn-belajar{
  display:inline-flex; align-items:center; justify-content:center; gap:8px;
  width:100%; padding:14px 20px; border-radius:14px;
  background:var(--grad-primary); color:#fff; font-weight:600; font-size:14.5px;
  transition:transform var(--transition), box-shadow var(--transition), gap var(--transition);
  box-shadow:0 8px 24px rgba(108,92,231,0.28);
}
.btn-belajar:hover{ gap:14px; box-shadow:0 12px 32px rgba(108,92,231,0.4); }
.btn-belajar.locked{ background:var(--glass); color:var(--text-faint); box-shadow:none; cursor:not-allowed; }

/* ---------- Hero ---------- */
.hero{
  position:relative;
  min-height:100vh;
  display:flex; flex-direction:column; align-items:center; justify-content:center;
  text-align:center;
  padding:calc(var(--nav-h) + 60px) 24px 100px;
  overflow:hidden;
}
.hero-eyebrow{
  display:inline-flex; align-items:center; gap:8px;
  padding:8px 18px; border-radius:100px;
  background:var(--glass); border:1px solid var(--glass-border);
  font-family:var(--font-mono); font-size:12.5px; letter-spacing:0.1em; text-transform:uppercase;
  color:var(--accent-2-soft); margin-bottom:28px;
}
.hero-eyebrow i{ color:var(--accent-2); }

.hero h1{
  font-size:clamp(2.4rem, 6vw, 4.6rem);
  line-height:1.08; max-width:920px;
  margin-bottom:24px;
}
.hero h1 .gradient-text{
  background:var(--grad-primary);
  -webkit-background-clip:text; background-clip:text; color:transparent;
}
.hero p.subtitle{
  max-width:640px; font-size:clamp(1rem,1.6vw,1.15rem); color:var(--text-muted);
  margin-bottom:44px;
}
.hero-actions{ display:flex; flex-wrap:wrap; gap:16px; justify-content:center; margin-bottom:64px; }

/* Hero mini stats strip */
.hero-stats{
  display:flex; flex-wrap:wrap; gap:0; justify-content:center;
  background:var(--glass); border:1px solid var(--glass-border);
  border-radius:var(--r-lg); padding:22px 8px; backdrop-filter:blur(20px);
  max-width:920px; width:100%;
}
.hero-stat{
  flex:1 1 140px; padding:10px 18px; text-align:center;
  border-right:1px solid var(--glass-border);
}
.hero-stat:last-child{ border-right:none; }
.hero-stat .num{
  font-family:var(--font-mono); font-size:clamp(1.5rem,3vw,2.1rem); font-weight:700; color:var(--text-hi);
  display:block;
}
.hero-stat .num .unit{ font-size:0.5em; color:var(--accent-2); }
.hero-stat .label{ font-size:12.5px; color:var(--text-faint); text-transform:uppercase; letter-spacing:0.06em; margin-top:4px; display:block; }

/* Scroll cue */
.scroll-cue{
  position:absolute; bottom:28px; left:50%; transform:translateX(-50%);
  display:flex; flex-direction:column; align-items:center; gap:8px;
  color:var(--text-faint); font-size:12px; letter-spacing:0.08em; text-transform:uppercase;
  animation:bob 2.4s ease-in-out infinite;
}
@keyframes bob{ 0%,100%{ transform:translate(-50%,0); } 50%{ transform:translate(-50%,8px); } }

/* ---------- Section shell ---------- */
.section{ padding:100px 24px; position:relative; }
.section-inner{ max-width:1300px; margin:0 auto; }
.section-head{ text-align:center; max-width:680px; margin:0 auto 60px; }
.section-eyebrow{
  font-family:var(--font-mono); font-size:12.5px; letter-spacing:0.14em; text-transform:uppercase;
  color:var(--accent-2); margin-bottom:14px; display:block;
}
.section-head h2{ font-size:clamp(1.8rem,3.6vw,2.6rem); margin-bottom:16px; }
.section-head p{ color:var(--text-muted); font-size:1.02rem; }

/* ---------- Dashboard / statistics ---------- */
.dash-grid{
  display:grid; grid-template-columns:repeat(auto-fit,minmax(150px,1fr));
  gap:16px;
}
.dash-card{
  background:var(--glass); border:1px solid var(--glass-border);
  border-radius:var(--r-md); padding:24px 20px;
  transition:transform var(--transition), border-color var(--transition), background var(--transition);
  position:relative; overflow:hidden;
}
.dash-card:hover{ transform:translateY(-6px); border-color:var(--glass-border-hi); background:var(--glass-strong); }
.dash-card i{ font-size:20px; color:var(--accent-2); margin-bottom:14px; display:block; }
.dash-card .val{ font-family:var(--font-mono); font-size:1.9rem; font-weight:700; color:var(--text-hi); }
.dash-card .lbl{ font-size:12.5px; color:var(--text-faint); text-transform:uppercase; letter-spacing:0.05em; margin-top:6px; }

/* ---------- Footer ---------- */
.site-footer{
  padding:80px 24px 40px;
  border-top:1px solid var(--glass-border);
  text-align:center;
  position:relative;
}
.footer-quote{
  font-family:var(--font-display); font-weight:600;
  font-size:clamp(1.3rem,2.6vw,1.9rem); color:var(--text-hi);
  max-width:720px; margin:0 auto 12px; line-height:1.4;
}
.footer-quote span{ color:var(--accent-2); }
.footer-sub{ color:var(--text-faint); font-size:13.5px; margin-bottom:36px; }
.footer-links{ display:flex; gap:22px; justify-content:center; flex-wrap:wrap; margin-bottom:30px; }
.footer-links a{ font-size:13.5px; color:var(--text-muted); }
.footer-links a:hover{ color:var(--accent-2); }
.footer-meta{ font-size:12.5px; color:var(--text-faint); font-family:var(--font-mono); }

/* ---------- Floating action button ---------- */
.fab{
  position:fixed; bottom:28px; right:28px; z-index:900;
  width:56px; height:56px; border-radius:50%;
  background:var(--grad-primary); color:#fff; font-size:18px;
  display:flex; align-items:center; justify-content:center;
  box-shadow:0 10px 30px rgba(108,92,231,0.45);
  opacity:0; visibility:hidden; transform:translateY(16px) scale(0.85);
  transition:all var(--transition);
}
.fab.visible{ opacity:1; visibility:visible; transform:translateY(0) scale(1); }
.fab:hover{ transform:translateY(-4px) scale(1.06); }

/* ---------- Utility ---------- */
.reveal{ opacity:0; transform:translateY(24px); transition:opacity 0.7s ease, transform 0.7s ease; }
.reveal.in-view{ opacity:1; transform:translateY(0); }
.text-gradient{ background:var(--grad-primary); -webkit-background-clip:text; background-clip:text; color:transparent; }

/* ---------- Responsive ---------- */
@media (max-width:900px){
  .nav-links{
    position:fixed; top:var(--nav-h); left:0; right:0;
    flex-direction:column; align-items:flex-start; gap:0;
    background:rgba(10,14,26,0.92); backdrop-filter:blur(18px);
    border-bottom:1px solid var(--glass-border);
    max-height:0; overflow:hidden; padding:0 24px;
    transition:max-height var(--transition), padding var(--transition);
    display:flex;
  }
  body.light-mode .nav-links{ background:rgba(255,255,255,0.94); }
  .nav-links.mobile-open{ max-height:320px; padding:16px 24px 24px; }
  .nav-links li{ width:100%; }
  .nav-links a{ display:block; padding:12px 0; width:100%; }
  .nav-toggle{ display:flex; }
}
@media (max-width:560px){
  .hero-stats{ padding:16px 4px; }
  .hero-stat{ flex:1 1 45%; border-right:none; border-bottom:1px solid var(--glass-border); padding:14px 8px; }
  .section{ padding:70px 16px; }
}