:root{
  --bg: #131826;
  --bg-panel: #1a2133;
  --bg-card: #212a40;
  --border: #2e3852;
  --text: #e7ebf5;
  --text-dim: #8b93ac;
  --accent-gold: #e8b04b;   /* fixed color for "M" always */
  --accent-teal: #4fd1c5;
  --accent-red: #ef5a6f;
  --accent-blue: #5c8df6;
  --radius: 12px;
  --font-display: 'Space Grotesk', sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
}

*{box-sizing:border-box;}
html,body{margin:0;padding:0;height:100%;}
body{
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-display);
  min-height:100vh;
}

.hidden{display:none !important;}

.m-accent{
  color: var(--accent-gold);
  font-weight:700;
}

/* ---------- Botones ---------- */
.btn{
  font-family: var(--font-display);
  font-weight:600;
  border:none;
  border-radius: 8px;
  padding: 10px 18px;
  cursor:pointer;
  font-size: 0.95rem;
  transition: transform .12s ease, opacity .12s ease;
}
.btn:hover{transform: translateY(-1px);}
.btn:active{transform: translateY(0);}
.btn-primary{ background: var(--accent-blue); color:#fff; }
.btn-verify{ background: var(--accent-teal); color:#0a1a18; }
.btn-reset{ background: transparent; color: var(--accent-red); border:1px solid var(--accent-red); }
.btn-ghost{ background: transparent; color: var(--text-dim); border:1px solid var(--border); }
.btn-danger{ background: var(--accent-red); color:#fff; }

/* ---------- Pantalla nombre ---------- */
.screen{ min-height:100vh; width:100%; }
#screen-name{
  display:flex; align-items:center; justify-content:center;
  padding: 24px;
  background: radial-gradient(circle at 30% 20%, #1c2540 0%, var(--bg) 60%);
}
.name-card{
  background: var(--bg-panel);
  border:1px solid var(--border);
  border-radius: var(--radius);
  padding: 36px 32px;
  max-width: 420px;
  width:100%;
  text-align:center;
}
.brand{
  font-family: var(--font-mono);
  letter-spacing: 2px;
  font-size: 1.1rem;
  color: var(--text-dim);
  margin-bottom: 18px;
}
.brand.small{ font-size:0.85rem; margin-bottom:0; }
.name-card h1{ margin: 0 0 8px; font-size:1.5rem; }
.name-card p{ color: var(--text-dim); font-size:0.92rem; margin: 0 0 20px; }
#input-name{
  width:100%;
  padding: 12px 14px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text);
  font-family: var(--font-display);
  font-size: 1rem;
  margin-bottom: 16px;
}
#input-name:focus{ outline: 2px solid var(--accent-blue); }
.field-error{ color: var(--accent-red); font-size:0.85rem; min-height: 18px; margin-top:10px;}

/* ---------- Topbar ---------- */
.topbar{
  display:flex; align-items:center; justify-content:space-between;
  padding: 12px 20px;
  background: var(--bg-panel);
  border-bottom: 1px solid var(--border);
  flex-wrap: wrap;
  gap: 10px;
}
.topbar-left{ display:flex; align-items:center; gap:16px; flex-wrap:wrap; }
.topbar-right{ display:flex; align-items:center; gap:10px; flex-wrap:wrap; }
.student-tag{ font-family: var(--font-mono); font-size:0.85rem; color: var(--text-dim); }
.progress-tag{ font-family: var(--font-mono); font-size:0.8rem; color: var(--text-dim); }

/* ---------- Layout principal ---------- */
.body-layout{ display:flex; min-height: calc(100vh - 60px); }
.sidebar{
  width: 240px;
  flex-shrink:0;
  background: var(--bg-panel);
  border-right: 1px solid var(--border);
  padding: 16px 10px;
  overflow-y:auto;
}
.folder-group{ margin-bottom: 22px; }
.folder-group-title{
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing:1px;
  text-transform:uppercase;
  color: var(--text-dim);
  padding: 0 8px 8px;
}
.folder-list{ display:flex; flex-direction:column; gap:4px; }
.folder-item{
  display:flex; align-items:center; justify-content:space-between;
  gap:8px;
  padding: 9px 10px;
  border-radius: 8px;
  cursor:pointer;
  font-size:0.88rem;
  border: 1px solid transparent;
}
.folder-item:hover{ background: var(--bg-card); }
.folder-item.active{ background: var(--bg-card); border-color: var(--accent-blue); }
.folder-item .fname{ display:flex; align-items:center; gap:8px; overflow:hidden; text-overflow:ellipsis; white-space:nowrap;}
.folder-count{
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-dim);
  background: #131826;
  padding: 1px 7px;
  border-radius: 10px;
  flex-shrink:0;
}
.folder-item.flash-error{ animation: flashError 0.6s ease-in-out infinite; }
@keyframes flashError{
  0%,100%{ background: var(--bg-card); border-color: var(--border); }
  50%{ background: rgba(239,90,111,0.25); border-color: var(--accent-red); }
}

/* ---------- Panel principal ---------- */
.main-panel{ flex:1; padding: 20px 24px; overflow-y:auto; }
.current-path{
  font-family: var(--font-mono);
  color: var(--text-dim);
  margin-bottom: 16px;
  font-size:0.95rem;
}
.file-grid{
  display:grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 14px;
}
.file-card{
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 14px 10px;
  text-align:center;
  cursor:pointer;
  transition: border-color .12s ease, background .12s ease;
}
.file-card:hover{ border-color: var(--accent-blue); background:#252f48; }
.file-icon{ font-size: 1.8rem; margin-bottom:8px; }
.file-name{
  font-family: var(--font-mono);
  font-size: 0.74rem;
  word-break: break-word;
  color: var(--text);
  line-height:1.3;
}
.empty-msg{ color: var(--text-dim); font-style:italic; margin-top: 20px; }

/* ---------- Modales ---------- */
.modal-overlay{
  position:fixed; inset:0;
  background: rgba(8,10,18,0.72);
  display:flex; align-items:center; justify-content:center;
  padding: 20px;
  z-index: 100;
}
.modal-box{
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px;
  max-width: 440px;
  width:100%;
}
.modal-box h3{ margin:0 0 10px; }
.modal-filename{
  font-family: var(--font-mono);
  background: var(--bg-card);
  padding: 8px 10px;
  border-radius: 6px;
  font-size: 0.85rem;
  word-break: break-word;
}
.modal-sub{ color: var(--text-dim); font-size:0.85rem; margin: 14px 0 10px; }
.modal-folder-options{
  display:grid;
  grid-template-columns: repeat(auto-fill, minmax(140px,1fr));
  gap: 8px;
  margin-bottom: 18px;
}
.modal-folder-btn{
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 8px;
  padding: 10px 8px;
  font-size: 0.82rem;
  cursor:pointer;
  text-align:center;
  font-family: var(--font-display);
}
.modal-folder-btn:hover{ border-color: var(--accent-blue); background:#252f48; }
.modal-actions{ display:flex; gap:10px; }
#verify-message{ color: var(--text-dim); white-space: pre-line; }

/* ---------- Pantalla final ---------- */
#screen-complete{
  display:flex; align-items:center; justify-content:center;
  padding:24px;
  background: radial-gradient(circle at 50% 30%, #1c2f2c 0%, var(--bg) 65%);
}
.complete-card{
  text-align:center;
  max-width: 480px;
  background: var(--bg-panel);
  border: 1px solid var(--accent-teal);
  border-radius: var(--radius);
  padding: 44px 32px;
}
.complete-icon{ font-size: 3rem; margin-bottom: 10px; }
.complete-card h1{ margin: 0 0 14px; }
.complete-card p{ color: var(--text-dim); }
.uplink-msg{
  margin-top: 24px;
  font-family: var(--font-mono);
  border: 1px dashed var(--accent-gold);
  border-radius: 8px;
  padding: 14px;
  font-size: 0.95rem;
}

/* ---------- Toast de verificación ---------- */
.toast{
  position: fixed;
  top: 18px;
  right: 18px;
  left: auto;
  z-index: 90;
  background: var(--bg-panel);
  border: 1px solid var(--accent-red);
  color: var(--text);
  padding: 12px 12px 12px 16px;
  border-radius: 10px;
  display:flex;
  align-items:center;
  justify-content: space-between;
  gap: 16px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  max-width: min(90vw, 360px);
  box-shadow: 0 8px 24px rgba(0,0,0,0.35);
}
.toast-close{
  background: var(--accent-red);
  border:none;
  color: #fff;
  cursor:pointer;
  font-size: 0.78rem;
  font-weight: 700;
  font-family: var(--font-display);
  padding: 7px 14px;
  border-radius: 7px;
  flex-shrink:0;
  margin-left: auto;
}
.toast-close:hover{ opacity: 0.88; }
@media (max-width: 460px){
  .toast{ left: 12px; right: 12px; top: 12px; max-width: none; }
}
@media (max-width: 780px){
  .body-layout{ flex-direction: column; }
  .sidebar{
    width:100%;
    border-right:none;
    border-bottom: 1px solid var(--border);
    display:flex;
    gap: 18px;
    overflow-x:auto;
  }
  .folder-group{ margin-bottom:0; flex-shrink:0; min-width: 200px; }
  .topbar{ flex-direction:column; align-items:flex-start; }
  .topbar-right{ width:100%; justify-content:flex-start; }
}
@media (max-width: 460px){
  .file-grid{ grid-template-columns: repeat(auto-fill, minmax(115px,1fr)); }
  .name-card{ padding: 26px 20px; }
}