/* ══════════════════════════════════════════
   KTI RFID-IoT — Stylesheet
   ══════════════════════════════════════════ */

*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
:root{
  --teal:#0F6E56;--teal-light:#E1F5EE;--teal-mid:#1D9E75;--teal-dark:#085041;
  --ink:#1a1a1a;--ink-soft:#3d3d3d;--muted:#6b7280;--border:#e5e7eb;
  --bg:#fafaf8;--white:#ffffff;
  --mono:'DM Mono',monospace;--serif:'DM Serif Display',Georgia,serif;
  --sans:'Plus Jakarta Sans',system-ui,sans-serif;
}
html{scroll-behavior:smooth}
body{font-family:var(--sans);background:var(--bg);color:var(--ink);line-height:1.7;font-size:16px}

/* ── LOADING SCREEN ── */
.loading-screen{
  position:fixed;inset:0;z-index:9999;
  background:#fafaf8;
  display:flex;flex-direction:column;align-items:center;justify-content:center;
  transition:opacity .5s ease,visibility .5s ease;
}
.loading-screen.hidden{
  opacity:0;visibility:hidden;pointer-events:none;
}
.loading-logo{
  width:100px;height:100px;
  animation:loadPulse 1.6s ease-in-out infinite;
  margin-bottom:1.5rem;
}
.loading-logo img{
  width:100%;height:100%;object-fit:contain;
  filter:drop-shadow(0 4px 20px rgba(15,110,86,.2));
}
.loading-bar-track{
  width:180px;height:4px;
  background:var(--border);border-radius:100px;
  overflow:hidden;margin-bottom:1rem;
}
.loading-bar-fill{
  width:0%;height:100%;
  background:linear-gradient(90deg,var(--teal),var(--teal-mid));
  border-radius:100px;
  animation:loadBar 1.8s ease-in-out forwards;
}
.loading-text{
  font-family:var(--mono);font-size:11px;
  color:var(--muted);letter-spacing:.1em;
  animation:loadFade 1s ease-in-out infinite alternate;
}
@keyframes loadPulse{
  0%,100%{transform:scale(1);opacity:1}
  50%{transform:scale(1.08);opacity:.85}
}
@keyframes loadBar{
  0%{width:0%}
  60%{width:70%}
  100%{width:100%}
}
@keyframes loadFade{
  0%{opacity:.4}
  100%{opacity:1}
}

/* ── NAV ── */
nav.topnav{
  position:sticky;top:0;z-index:200;
  background:rgba(250,250,248,.93);backdrop-filter:blur(14px);
  border-bottom:1px solid var(--border);
  padding:0 clamp(1.25rem,4vw,4rem);
  display:flex;align-items:center;justify-content:space-between;
  height:60px;gap:1rem;
}
.nav-left{display:flex;align-items:center;gap:.75rem}
.nav-logo-wrap{display:flex;align-items:center;gap:10px;text-decoration:none}
.logo-img{height:34px;width:auto;object-fit:contain;transition:transform .2s ease}
.nav-logo-wrap:hover .logo-img{transform:scale(1.06)}
.nav-logo-text{font-family:var(--mono);font-size:12px;color:var(--teal);letter-spacing:.05em;font-weight:500;white-space:nowrap}
.nav-right{display:flex;align-items:center;gap:.5rem}
.nav-links{display:flex;align-items:center;gap:.1rem;list-style:none}
.nav-links a{
  font-size:13px;color:var(--muted);text-decoration:none;font-weight:500;
  padding:6px 10px;border-radius:6px;white-space:nowrap;transition:color .2s,background .2s;
}
.nav-links a:hover{color:var(--teal);background:var(--teal-light)}

/* language toggle */
.lang-toggle{
  display:flex;align-items:center;
  background:var(--bg);border:1px solid var(--border);border-radius:100px;padding:3px;gap:2px;flex-shrink:0;
}
.lang-btn{
  font-family:var(--mono);font-size:11px;font-weight:600;padding:4px 10px;
  border-radius:100px;border:none;background:transparent;color:var(--muted);
  cursor:pointer;transition:all .2s;letter-spacing:.05em;
}
.lang-btn.active{background:var(--teal);color:#fff}

/* hamburger */
.hamburger{
  display:none;flex-direction:column;gap:5px;cursor:pointer;
  padding:6px;border:none;background:transparent;border-radius:6px;transition:background .2s;
}
.hamburger:hover{background:var(--teal-light)}
.hamburger span{display:block;width:22px;height:2px;background:var(--ink-soft);border-radius:2px;transition:all .3s}
.hamburger.open span:nth-child(1){transform:translateY(7px) rotate(45deg)}
.hamburger.open span:nth-child(2){opacity:0}
.hamburger.open span:nth-child(3){transform:translateY(-7px) rotate(-45deg)}

/* mobile drawer */
.mobile-drawer{
  display:none;position:fixed;top:60px;left:0;right:0;
  background:rgba(250,250,248,.97);backdrop-filter:blur(14px);
  border-bottom:1px solid var(--border);
  padding:1rem 1.25rem 1.5rem;
  flex-direction:column;gap:4px;z-index:199;
  opacity:0;transform:translateY(-10px);transition:opacity .25s,transform .25s;
}
.mobile-drawer.open{display:flex;opacity:1;transform:translateY(0)}
.mobile-drawer a{
  font-size:15px;color:var(--ink-soft);text-decoration:none;font-weight:500;
  padding:10px 12px;border-radius:8px;transition:background .15s,color .15s;
}
.mobile-drawer a:hover{background:var(--teal-light);color:var(--teal)}
.mdrawer-lang{display:flex;gap:8px;padding:12px 12px 2px;align-items:center}
.mdrawer-lang-label{font-size:12px;color:var(--muted);font-family:var(--mono)}

@media(max-width:768px){
  .nav-links{display:none}
  .hamburger{display:flex}
}

/* ── HERO ── */
.hero{
  min-height:92vh;display:flex;flex-direction:column;justify-content:center;
  padding:clamp(5rem,10vw,8rem) clamp(1.25rem,4vw,4rem) clamp(3rem,6vw,5rem);
  position:relative;overflow:hidden;
}
.hero::before{
  content:'';position:absolute;top:0;right:0;
  width:55%;height:100%;
  background:linear-gradient(135deg,var(--teal-light) 0%,#E1F5EE 60%,var(--bg) 100%);
  clip-path:polygon(15% 0,100% 0,100% 100%,0% 100%);z-index:0;
}
@media(max-width:640px){.hero::before{width:100%;clip-path:none;opacity:.3}}
.hero-content{position:relative;z-index:1;max-width:760px}
.hero-badge{
  display:inline-flex;align-items:center;gap:8px;
  background:var(--white);border:1px solid var(--border);border-radius:100px;
  padding:6px 16px;font-size:12px;font-family:var(--mono);color:var(--teal);
  margin-bottom:1.75rem;font-weight:500;
}
.hero-badge::before{content:'';width:7px;height:7px;border-radius:50%;background:var(--teal-mid);display:block}
.hero h1{
  font-family:var(--serif);font-size:clamp(2rem,4.5vw,3.6rem);
  line-height:1.15;color:var(--ink);margin-bottom:1.5rem;font-weight:400;
}
.hero h1 em{color:var(--teal);font-style:italic}
.hero-meta{display:flex;flex-wrap:wrap;gap:1.25rem 2rem;margin-bottom:2.5rem}
.hero-meta-item{display:flex;flex-direction:column}
.hero-meta-label{font-size:10px;font-family:var(--mono);color:var(--muted);letter-spacing:.1em;text-transform:uppercase;margin-bottom:2px}
.hero-meta-value{font-size:14px;font-weight:600;color:var(--ink-soft)}
.hero-actions{display:flex;gap:.75rem;flex-wrap:wrap}

/* hero device photo */
.hero-device{
  position:absolute;right:clamp(1rem,5vw,5rem);top:50%;transform:translateY(-50%);
  z-index:1;width:clamp(200px,27vw,370px);
}
.hero-device-frame{
  background:var(--white);border:1px solid var(--border);border-radius:18px;overflow:hidden;
  box-shadow:0 8px 30px rgba(15,110,86,.12);aspect-ratio:4/3;
  display:flex;align-items:center;justify-content:center;flex-direction:column;gap:.75rem;
}
.hero-device-frame img{width:100%;height:100%;object-fit:cover;display:block}
.device-ph{display:flex;flex-direction:column;align-items:center;gap:.5rem;padding:1.5rem;text-align:center}
.device-ph i{font-size:2.2rem;color:var(--teal-mid)}
.device-ph p{font-size:11px;color:var(--muted);line-height:1.5;font-family:var(--mono)}
.hero-device-caption{text-align:center;font-size:11px;color:var(--muted);margin-top:8px;font-family:var(--mono)}
@media(max-width:900px){.hero-device{display:none}.hero-content{max-width:100%}}

.scroll-hint{
  position:absolute;bottom:2rem;left:clamp(1.25rem,4vw,4rem);
  font-size:12px;font-family:var(--mono);color:var(--muted);letter-spacing:.05em;
  display:flex;align-items:center;gap:8px;z-index:1;
  animation:bounce 2.2s ease-in-out infinite;
}
.scroll-hint::after{content:'↓';font-size:14px}
@keyframes bounce{0%,100%{transform:translateY(0)}50%{transform:translateY(6px)}}

/* ── BUTTONS ── */
.btn{
  display:inline-flex;align-items:center;gap:8px;
  padding:11px 22px;border-radius:8px;font-size:14px;font-weight:600;
  text-decoration:none;transition:all .2s;cursor:pointer;border:none;font-family:var(--sans);
}
.btn-primary{background:var(--teal);color:#fff}
.btn-primary:hover{background:var(--teal-dark);transform:translateY(-2px)}
.btn-outline{background:transparent;color:var(--teal);border:1.5px solid var(--teal)}
.btn-outline:hover{background:var(--teal-light);transform:translateY(-2px)}

/* ── SECTION BASE ── */
section{padding:clamp(3.5rem,7vw,6rem) clamp(1.25rem,4vw,4rem)}
.section-label{font-family:var(--mono);font-size:11px;letter-spacing:.12em;text-transform:uppercase;color:var(--teal);margin-bottom:.6rem;font-weight:500}
.section-title{font-family:var(--serif);font-size:clamp(1.6rem,3vw,2.4rem);font-weight:400;color:var(--ink);line-height:1.25;margin-bottom:.75rem}
.section-sub{font-size:15px;color:var(--muted);max-width:600px;margin-bottom:3rem;line-height:1.8}

/* ── ABOUT ── */
.about{background:var(--white);border-top:1px solid var(--border);border-bottom:1px solid var(--border)}
.about-grid{display:grid;grid-template-columns:1fr 1fr;gap:4rem;align-items:start}
@media(max-width:768px){.about-grid{grid-template-columns:1fr;gap:2.5rem}}
.about-text{font-size:15.5px;line-height:1.9;color:var(--ink-soft)}
.about-text p+p{margin-top:1rem}
.about-sidebar{display:flex;flex-direction:column;gap:1rem}
.stat-card{background:var(--bg);border:1px solid var(--border);border-radius:12px;padding:1.1rem 1.4rem;display:flex;flex-direction:column;gap:4px}
.stat-num{font-family:var(--serif);font-size:2rem;color:var(--teal);line-height:1}
.stat-label{font-size:13px;color:var(--muted);font-weight:500}

/* device gallery */
.device-gallery{display:grid;grid-template-columns:1fr 1fr;gap:1rem;margin-top:2rem}
@media(max-width:500px){.device-gallery{grid-template-columns:1fr}}
.device-slot{
  background:var(--bg);border:1.5px dashed var(--teal-mid);border-radius:14px;
  overflow:hidden;aspect-ratio:4/3;
  display:flex;align-items:center;justify-content:center;flex-direction:column;gap:.5rem;
}
.device-slot img{width:100%;height:100%;object-fit:cover;display:block}
.device-slot-ph{text-align:center;padding:1rem}
.device-slot-ph i{font-size:1.6rem;color:var(--teal-mid);display:block;margin-bottom:6px}
.device-slot-ph p{font-size:11px;color:var(--muted);font-family:var(--mono);line-height:1.5}

/* ── TECH ── */
.tech{background:var(--bg)}
.tech-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:1.1rem}
.tech-card{background:var(--white);border:1px solid var(--border);border-radius:14px;padding:1.4rem;transition:border-color .2s,transform .2s}
.tech-card:hover{border-color:var(--teal-mid);transform:translateY(-3px)}
.tech-icon{width:42px;height:42px;border-radius:10px;background:var(--teal-light);display:flex;align-items:center;justify-content:center;margin-bottom:.9rem;font-size:1.15rem;color:var(--teal)}
.tech-name{font-weight:600;font-size:14px;color:var(--ink);margin-bottom:4px}
.tech-desc{font-size:13px;color:var(--muted);line-height:1.6}

/* ── CHAPTERS ── */
.chapters{background:var(--white);border-top:1px solid var(--border)}
.chapter-list{display:flex;flex-direction:column}
.chapter-item{display:flex;align-items:flex-start;gap:2rem;padding:1.6rem 0;border-bottom:1px solid var(--border)}
.chapter-item:last-child{border-bottom:none}
.chapter-num{font-family:var(--mono);font-size:12px;color:var(--teal);font-weight:500;min-width:55px;padding-top:3px;letter-spacing:.04em;flex-shrink:0}
.chapter-title{font-weight:600;font-size:15px;color:var(--ink);margin-bottom:4px}
.chapter-topics{font-size:13px;color:var(--muted);line-height:1.6}

/* ── PDF ── */
.pdf-section{background:#1a1a1a;color:#fff}
.pdf-section .section-label{color:var(--teal-mid)}
.pdf-section .section-title{color:#fff}
.pdf-section .section-sub{color:#9ca3af}
.pdf-wrapper{background:#0f0f0f;border-radius:16px;overflow:hidden;border:1px solid #2d2d2d}
.pdf-toolbar{background:#2d2d2d;padding:12px 20px;display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:10px}
.pdf-filename{font-size:13px;color:#d1d5db;font-family:var(--mono)}
.pdf-dl{
  display:inline-flex;align-items:center;gap:6px;background:var(--teal);color:#fff;
  border:none;border-radius:6px;padding:7px 16px;font-size:13px;font-weight:600;
  cursor:pointer;text-decoration:none;transition:background .2s;font-family:var(--sans);
}
.pdf-dl:hover{background:var(--teal-dark)}
.pdf-fallback{padding:3rem 2rem;text-align:center;color:#6b7280}
.pdf-fallback-icon{width:56px;height:56px;background:#2d2d2d;border-radius:14px;display:flex;align-items:center;justify-content:center;margin:0 auto 1rem;font-size:1.5rem;color:#9ca3af}
.pdf-fallback h3{color:#d1d5db;font-size:16px;margin-bottom:8px}
.pdf-fallback p{font-size:14px;line-height:1.7;max-width:420px;margin:0 auto}
.pdf-fallback code{background:#2d2d2d;padding:2px 8px;border-radius:4px;font-size:13px}

/* ── SERTIFIKAT ── */
.cert-section{background:#0f1117;color:#fff;position:relative;overflow:hidden}
.cert-section::before{
  content:'';position:absolute;top:-60px;right:-60px;
  width:320px;height:320px;border-radius:50%;
  background:radial-gradient(circle,rgba(212,170,80,.12) 0%,transparent 70%);
  pointer-events:none;
}
.cert-section .section-label{color:#d4aa50}
.cert-section .section-title{color:#fff}
.cert-section .section-sub{color:#9ca3af}
.cert-header-row{
  display:flex;align-items:center;gap:1rem;margin-bottom:2rem;
}
.cert-badge-icon{
  width:52px;height:52px;border-radius:14px;
  background:linear-gradient(135deg,#d4aa50,#f0c84a);
  display:flex;align-items:center;justify-content:center;
  font-size:1.5rem;color:#fff;flex-shrink:0;
  box-shadow:0 4px 18px rgba(212,170,80,.35);
}
.cert-wrapper{background:#181b24;border-radius:16px;overflow:hidden;border:1px solid #2a2d38}
.cert-toolbar{
  background:linear-gradient(90deg,#1e2130,#252836);
  padding:14px 20px;display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:10px;
  border-bottom:1px solid #2a2d38;
}
.cert-filename{font-size:13px;color:#d1d5db;font-family:var(--mono);display:flex;align-items:center;gap:8px}
.cert-filename i{color:#d4aa50;font-size:15px}
.cert-dl{
  display:inline-flex;align-items:center;gap:7px;
  background:linear-gradient(135deg,#d4aa50,#f0c84a);color:#1a1300;
  border:none;border-radius:8px;padding:8px 18px;font-size:13px;font-weight:700;
  cursor:pointer;text-decoration:none;transition:all .2s;font-family:var(--sans);
  box-shadow:0 2px 10px rgba(212,170,80,.3);
}
.cert-dl:hover{transform:translateY(-2px);box-shadow:0 6px 20px rgba(212,170,80,.45)}
.cert-fallback{padding:3rem 2rem;text-align:center;color:#6b7280}
.cert-fallback-icon{width:56px;height:56px;background:#2a2d38;border-radius:14px;display:flex;align-items:center;justify-content:center;margin:0 auto 1rem;font-size:1.5rem;color:#d4aa50}
.cert-fallback h3{color:#d1d5db;font-size:16px;margin-bottom:8px}
.cert-fallback p{font-size:14px;line-height:1.7;max-width:420px;margin:0 auto}
.cert-info-row{
  display:flex;gap:1rem;flex-wrap:wrap;margin-top:1.5rem;
}
.cert-info-chip{
  display:inline-flex;align-items:center;gap:7px;
  background:#1e2130;border:1px solid #2a2d38;
  border-radius:100px;padding:7px 16px;
  font-size:12px;color:#9ca3af;font-family:var(--mono);
}
.cert-info-chip i{color:#d4aa50;font-size:13px}

/* ── AUTHOR ── */
.author{background:var(--bg);border-top:1px solid var(--border)}
.author-card{
  background:var(--white);border:1px solid var(--border);border-radius:20px;
  padding:2.25rem 2.5rem;display:flex;gap:2.5rem;align-items:flex-start;max-width:740px;
}
@media(max-width:600px){.author-card{flex-direction:column;text-align:center;padding:1.75rem;gap:1.5rem}}
.author-avatar-wrap{flex-shrink:0;text-align:center}
.author-avatar{
  width:88px;height:88px;border-radius:50%;border:2.5px solid var(--teal-mid);overflow:hidden;
  display:flex;align-items:center;justify-content:center;background:var(--teal-light);margin-bottom:6px;
}
.author-avatar img{width:100%;height:100%;object-fit:cover;display:block}
.avatar-initials{font-family:var(--serif);font-size:2.2rem;color:var(--teal)}
.avatar-hint{font-size:10px;color:var(--muted);font-family:var(--mono);white-space:nowrap}
.author-info{flex:1}
.author-name{font-family:var(--serif);font-size:1.45rem;color:var(--ink);margin-bottom:2px}
.author-school{font-size:12px;color:var(--teal);font-weight:600;margin-bottom:.75rem;font-family:var(--mono);letter-spacing:.04em}
.author-bio{font-size:14px;color:var(--muted);line-height:1.7}
.author-tags{display:flex;flex-wrap:wrap;gap:6px;margin-top:1rem}
@media(max-width:600px){.author-tags,.social-row{justify-content:center}}
.tag{background:var(--teal-light);color:var(--teal-dark);font-size:12px;font-weight:600;padding:4px 12px;border-radius:100px}

/* social buttons */
.social-row{display:flex;flex-wrap:wrap;gap:8px;margin-top:1.25rem}
.social-btn{
  display:inline-flex;align-items:center;gap:7px;
  padding:8px 14px;border-radius:8px;font-size:13px;font-weight:600;
  text-decoration:none;border:1.5px solid var(--border);
  color:var(--ink-soft);background:var(--bg);transition:all .2s;white-space:nowrap;
}
.social-btn i{font-size:15px}
.social-btn:hover{border-color:var(--teal-mid);color:var(--teal);background:var(--teal-light);transform:translateY(-2px)}
.social-btn.li:hover{background:#EBF2FA;border-color:#0A66C2;color:#0A66C2}
.social-btn.ig:hover{background:#FDF0F5;border-color:#E1306C;color:#E1306C}
.social-btn.wb:hover{background:#F0F5FF;border-color:#3B5BDB;color:#3B5BDB}

/* ── FOOTER ── */
footer{
  background:var(--ink);color:#9ca3af;
  padding:2rem clamp(1.25rem,4vw,4rem);font-size:13px;font-family:var(--mono);
}
.footer-inner{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:1rem}
.footer-copy span{color:var(--teal-mid)}
.footer-social{display:flex;gap:14px}
.footer-social a{color:#6b7280;font-size:17px;transition:color .2s;text-decoration:none}
.footer-social a:hover{color:var(--teal-mid)}

/* ── ANIMATIONS ── */
.fade-in{opacity:0;transform:translateY(22px);transition:opacity .55s ease,transform .55s ease}
.fade-in.visible{opacity:1;transform:translateY(0)}