/* ── THEORY / CONCEPT CARDS ── */
.concept-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 18px;
  margin-top: 52px;
}

.concept-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 26px;
  transition: border-color .25s, transform .25s;
}
.concept-card:hover { border-color: rgba(180, 83, 9, .3); transform: translateY(-3px); }

.concept-head { display: flex; align-items: center; gap: 12px; margin-bottom: 10px; }
.concept-ico  { font-size: 22px; }
.concept-head h4 { font-family: var(--fh); font-size: 15px; font-weight: 600; }

.concept-card > p { font-size: 13px; color: var(--t2); line-height: 1.65; margin-bottom: 14px; }

.code-block {
  background: #292524;
  border: 1px solid rgba(255,255,255,.1);
  border-radius: 8px;
  padding: 13px 15px;
  font-family: var(--fm);
  font-size: 11.5px;
  line-height: 1.7;
  overflow-x: auto;
  white-space: pre;
  color: #a8a29e;
  margin: 0;
}
.c-k { color: #b45309; }   /* keyword / type */
.c-f { color: #0f766e; }   /* function */
.c-s { color: #ffd080; }   /* string */
.c-c { color: #444458; }   /* comment */
.c-n { color: #ff9d6c; }   /* number */

/* ── SELECT / DROPDOWN ── */
.custom-dd {
  position: relative;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 9px 13px;
  font-size: 13.5px;
  color: var(--t2);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  user-select: none;
  transition: border-color .2s;
}
.custom-dd:hover { border-color: rgba(180, 83, 9, .4); }
.custom-dd.open  { border-color: rgba(180, 83, 9, .5); }
.dd-arr { font-size: 12px; transition: transform .2s; }
.custom-dd.open .dd-arr { transform: rotate(180deg); }

.dd-menu {
  display: none;
  position: absolute;
  top: calc(100% + 6px);
  left: 0; right: 0;
  background: var(--surface);
  border: 1px solid var(--border2);
  border-radius: 10px;
  overflow: hidden;
  z-index: 10;
  box-shadow: 0 12px 32px rgba(0,0,0,.4);
}
.custom-dd.open .dd-menu { display: block; }

.dd-opt {
  padding: 11px 15px;
  font-size: 13px;
  color: var(--t2);
  cursor: pointer;
  transition: all .15s;
}
.dd-opt:hover { background: rgba(180, 83, 9, .1); color: var(--a); }

/* ── IFRAME ── */
.iframe-wrap {
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
}
.demo-iframe {
  width: 100%;
  height: 180px;
  border: none;
  display: block;
}

/* ── FILE UPLOAD ── */
.upload-label {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--bg);
  border: 2px dashed var(--border2);
  border-radius: 10px;
  padding: 18px 20px;
  font-size: 13.5px;
  color: var(--t2);
  cursor: pointer;
  transition: all .2s;
}
.upload-label:hover { border-color: var(--a); color: var(--a); background: rgba(180, 83, 9, .04); }
.upload-ico { font-size: 22px; }

/* ── LINKS ── */
.demo-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 13.5px;
  color: var(--a);
  text-decoration: none;
  padding: 8px 14px;
  background: rgba(180, 83, 9, .07);
  border: 1px solid rgba(180, 83, 9, .2);
  border-radius: 8px;
  transition: all .2s;
  width: fit-content;
}
.demo-link:hover { background: rgba(180, 83, 9, .14); transform: translateX(4px); }
.demo-link-broken { color: var(--a3); background: rgba(220, 38, 38, .07); border-color: rgba(220, 38, 38, .2); }
.demo-link-broken:hover { background: rgba(220, 38, 38, .12); }

/* ── ACADEMY BANNER ── */
.acad-banner {
  border-radius: 22px;
  padding: 60px;
  text-align: center;
  position: relative;
  overflow: hidden;
  margin-bottom: 56px;
  background: var(--surface);
  border: 1px solid var(--border);
}
.acad-banner::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse 70% 60% at 50% 100%, rgba(180, 83, 9, .12), transparent 70%);
}
.acad-badge {
  display: inline-block;
  font-family: var(--fm);
  font-size: 11px;
  color: var(--a);
  background: rgba(180, 83, 9, .1);
  border: 1px solid rgba(180, 83, 9, .25);
  padding: 5px 16px;
  border-radius: 40px;
  margin-bottom: 20px;
}
.acad-banner h2 { font-family: var(--fh); font-size: 36px; font-weight: 700; margin-bottom: 12px; position: relative; }
.acad-banner p  { color: var(--t2); font-size: 15px; max-width: 500px; margin: 0 auto; position: relative; }

/* ── MANUAL LAB ── */
#manual { background: var(--bg); }

.ex-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 16px;
  margin-bottom: 48px;
}

.ex-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 22px;
  cursor: none;
  transition: all .25s;
}
.ex-card:hover { border-color: rgba(180, 83, 9, .35); transform: translateY(-3px); }

.ex-emo   { font-size: 26px; margin-bottom: 10px; }
.ex-title { font-family: var(--fh); font-size: 15px; font-weight: 600; margin-bottom: 4px; }
.ex-meta  { font-size: 12px; color: var(--t3); margin-bottom: 14px; display: flex; justify-content: space-between; align-items: center; }

.diff { font-family: var(--fm); font-size: 10px; padding: 2px 8px; border-radius: 4px; }
.diff.e { background: rgba(15, 118, 110, .1);   color: var(--a2); }
.diff.m { background: rgba(180, 83, 9, .1);  color: var(--a);  }
.diff.h { background: rgba(220, 38, 38, .1);  color: var(--a3); }

.prog-bar  { height: 3px; background: rgba(28, 25, 23, .1); border-radius: 40px; overflow: hidden; }
.prog-fill { height: 100%; border-radius: 40px; background: var(--a); width: 0%; transition: width 1.2s cubic-bezier(.25, .46, .45, .94); }

/* Buggy Demo Browser */
.bug-badge {
  font-family: var(--fm);
  font-size: 10px;
  background: var(--a3);
  color: #fff;
  padding: 3px 9px;
  border-radius: 4px;
  margin-left: 8px;
}

.browser { background: var(--surface2); border: 1px solid var(--border); border-radius: 16px; overflow: hidden; margin-top: 16px; }

.browser-bar {
  background: var(--surface);
  padding: 12px 16px;
  display: flex; align-items: center; gap: 10px;
  border-bottom: 1px solid var(--border);
}

.bd { width: 11px; height: 11px; border-radius: 50%; }

.b-url {
  flex: 1;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 5px 12px;
  font-family: var(--fm);
  font-size: 11.5px;
  color: var(--t3);
}

.browser-body { padding: 28px; display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }

.fg      { display: flex; flex-direction: column; gap: 6px; grid-column: span 1; }
.fg.full { grid-column: span 2; }

.flabel { font-size: 12.5px; color: var(--t2); font-family: var(--fm); }

.finput {
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--t);
  padding: 9px 13px;
  border-radius: 8px;
  font-size: 13.5px;
  font-family: var(--fb);
  outline: none;
  transition: border-color .2s;
  width: 100%;
}
.finput:focus { border-color: rgba(180, 83, 9, .5); }
.finput.bug   { border-color: rgba(220, 38, 38, .35); background: rgba(220, 38, 38, .04); }

.fbtn {
  background: var(--a);
  color: #fff;
  padding: 10px;
  border-radius: 8px;
  font-size: 14px;
  border: none;
  cursor: pointer;
  width: 100%;
  font-family: var(--fb);
  font-weight: 500;
  grid-column: span 2;
  transition: all .2s;
}
.fbtn:hover { background: #c46c10; }

/* ── AUTO LAB ── */
#auto { background: var(--bg2); }

.auto-wrap {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 32px;
  margin-top: 32px;
}

.auto-nav {
  display: flex;
  flex-direction: column;
  gap: 3px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 12px;
  height: fit-content;
}

.anav-item {
  padding: 10px 14px;
  border-radius: 10px;
  font-size: 13.5px;
  color: var(--t2);
  cursor: none;
  transition: all .15s;
  border: none;
  background: transparent;
  font-family: var(--fb);
  width: 100%;
  text-align: left;
  display: flex; align-items: center; gap: 9px;
}
.anav-item:hover  { background: var(--surface2); color: var(--t); }
.anav-item.active { background: rgba(180, 83, 9, .15); color: var(--a); }

.adot { width: 5px; height: 5px; border-radius: 50%; background: currentColor; opacity: .5; flex-shrink: 0; }

.auto-stage {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 36px;
  min-height: 360px;
}

.el-sec        { display: none; }
.el-sec.active { display: block; }
.el-sec h3     { font-family: var(--fh); font-size: 19px; font-weight: 600; margin-bottom: 8px; }
.el-sec .el-sub{ font-size: 13px; color: var(--t2); margin-bottom: 28px; }

.demo-row { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; margin-bottom: 20px; }

.dbtn {
  padding: 10px 22px;
  border-radius: 9px;
  font-size: 13.5px;
  cursor: pointer;
  font-family: var(--fb);
  transition: all .2s;
  border: 1px solid transparent;
}
.dbtn.p { background: var(--a); color: #fff; border-color: var(--a); }
.dbtn.p:hover { background: #c46c10; }
.dbtn.s { background: transparent; border-color: var(--border2); color: var(--t2); }
.dbtn.s:hover { border-color: var(--a); color: var(--a); }
.dbtn.d { background: transparent; border-color: rgba(220, 38, 38, .3); color: var(--a3); }
.dbtn.d:hover { background: rgba(220, 38, 38, .07); }

.loc-hint {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 14px 18px;
  margin-top: 18px;
}
.loc-code { font-family: var(--fm); font-size: 11.5px; color: var(--a2); margin-bottom: 2px; }
.loc-sub  { font-family: var(--fm); font-size: 10.5px; color: var(--t3); }
.copy-btn {
  float: right;
  font-family: var(--fm);
  font-size: 10px;
  background: rgba(15, 118, 110, .1);
  color: var(--a2);
  padding: 3px 10px;
  border-radius: 4px;
  cursor: pointer;
  border: none;
  transition: all .2s;
}
.copy-btn:hover { background: rgba(15, 118, 110, .2); }

/* Web Table */
.dtable { width: 100%; border-collapse: collapse; font-size: 13.5px; }
.dtable th { padding: 10px 14px; text-align: left; font-size: 11px; color: var(--t3); border-bottom: 1px solid var(--border); font-family: var(--fm); font-weight: 400; }
.dtable td { padding: 12px 14px; border-bottom: 1px solid var(--border); color: var(--t2); }
.dtable tr:hover td { color: var(--t); background: rgba(255, 255, 255, .015); }
.sbadge { font-family: var(--fm); font-size: 10px; padding: 2px 8px; border-radius: 4px; display: inline-block; }

/* Sliders */
.sslider-wrap { margin-bottom: 22px; }
.sslider-label { font-size: 12.5px; color: var(--t2); margin-bottom: 9px; display: flex; justify-content: space-between; }

input[type="range"].drange {
  width: 100%; height: 4px;
  -webkit-appearance: none;
  background: var(--surface2);
  border-radius: 40px;
  outline: none;
  cursor: pointer;
}
input[type="range"].drange::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 18px; height: 18px;
  border-radius: 50%;
  background: var(--a);
  cursor: pointer;
  transition: transform .2s;
  box-shadow: 0 0 12px rgba(180, 83, 9, .5);
}
input[type="range"].drange::-webkit-slider-thumb:hover { transform: scale(1.25); }

/* Checkbox & Radio */
.dcheck-row { display: flex; align-items: center; gap: 10px; margin-bottom: 13px; cursor: pointer; font-size: 14px; color: var(--t2); }

input[type="checkbox"].dcheck {
  width: 17px; height: 17px;
  border-radius: 5px;
  -webkit-appearance: none;
  border: 1.5px solid var(--border2);
  background: transparent;
  cursor: pointer;
  transition: all .15s;
  flex-shrink: 0;
  position: relative;
}
input[type="checkbox"].dcheck:checked { background: var(--a); border-color: var(--a); }
input[type="checkbox"].dcheck:checked::after {
  content: '✓';
  position: absolute;
  top: 50%; left: 50%;
  transform: translate(-50%, -52%);
  font-size: 10px;
  color: #fff;
}

/* Drag & Drop */
.draggable-item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--surface2);
  border: 1px solid var(--border);
  padding: 9px 16px;
  border-radius: 8px;
  font-size: 13px;
  cursor: grab;
  margin: 6px;
  transition: all .2s;
  user-select: none;
}
.draggable-item:active { cursor: grabbing; opacity: .7; transform: scale(.97); }

.drop-zone {
  border: 2px dashed var(--border2);
  border-radius: 10px;
  padding: 20px;
  min-height: 70px;
  display: flex; align-items: center; justify-content: center;
  font-size: 13px;
  color: var(--t3);
  flex-wrap: wrap;
  gap: 8px;
  transition: all .2s;
}
.drop-zone.over { border-color: var(--a2); background: rgba(15, 118, 110, .04); }

/* ── MODAL ── */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, .75);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 500;
  backdrop-filter: blur(6px);
}
.modal-overlay.show { display: flex; }

.modal-box {
  background: var(--surface);
  border: 1px solid var(--border2);
  border-radius: 22px;
  padding: 44px;
  max-width: 400px;
  width: 90%;
  animation: mfade .25s ease;
}
.modal-box h3 { font-family: var(--fh); font-size: 20px; font-weight: 600; margin-bottom: 10px; }
.modal-box p  { font-size: 14px; color: var(--t2); margin-bottom: 28px; }
.modal-close  { background: var(--a); color: #fff; border: none; padding: 10px 24px; border-radius: 40px; cursor: pointer; font-family: var(--fb); font-size: 14px; }

/* ── MANUAL LAB — BLACK BOX / BUG REPORT / TEST CASE ── */

/* Section divider */
.lab-section {
  margin-top: 72px;
}
.lab-section-head {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 24px;
}
.lab-section-head h3 {
  font-family: var(--fh);
  font-size: 18px;
  font-weight: 600;
}

/* Black box technique cards */
.bb-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 16px;
}
.bb-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 22px;
  transition: border-color .25s, transform .25s;
}
.bb-card:hover { border-color: rgba(180,83,9,.3); transform: translateY(-3px); }
.bb-card-top {
  display: flex; align-items: flex-start; gap: 14px; margin-bottom: 10px;
}
.bb-ico {
  width: 40px; height: 40px; border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  font-size: 18px; flex-shrink: 0;
  background: rgba(180,83,9,.1);
}
.bb-card h4 { font-family: var(--fh); font-size: 14.5px; font-weight: 600; margin-bottom: 4px; }
.bb-card > p { font-size: 12.5px; color: var(--t2); line-height: 1.65; margin-bottom: 12px; }
.bb-example {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 11px 14px;
  font-family: var(--fm);
  font-size: 11px;
  color: var(--t3);
  line-height: 1.7;
}
.bb-example strong { color: var(--a2); font-weight: 500; }

/* Bug Report */
.bug-report-wrap {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  overflow: hidden;
}
.bug-report-header {
  background: rgba(220,38,38,.06);
  border-bottom: 1px solid var(--border);
  padding: 18px 24px;
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: 12px;
}
.bug-report-header h4 { font-family: var(--fh); font-size: 15px; font-weight: 600; }
.bug-id  { font-family: var(--fm); font-size: 11px; color: var(--a3); background: rgba(220,38,38,.1); border: 1px solid rgba(220,38,38,.2); padding: 3px 10px; border-radius: 4px; }
.bug-body { padding: 24px; display: grid; gap: 0; }
.bug-row {
  display: grid;
  grid-template-columns: 140px 1fr;
  border-bottom: 1px solid var(--border);
  min-height: 44px;
}
.bug-row:last-child { border-bottom: none; }
.bug-label {
  padding: 12px 16px 12px 0;
  font-family: var(--fm);
  font-size: 11.5px;
  color: var(--t3);
  font-weight: 500;
  display: flex; align-items: flex-start; padding-top: 14px;
}
.bug-val {
  padding: 12px 0;
  font-size: 13.5px;
  color: var(--t2);
  line-height: 1.6;
}
.bug-val code {
  font-family: var(--fm);
  font-size: 12px;
  background: var(--bg);
  border: 1px solid var(--border);
  padding: 1px 7px;
  border-radius: 4px;
  color: var(--a2);
}
.sev-tag {
  display: inline-flex; align-items: center; gap: 5px;
  font-family: var(--fm); font-size: 11px;
  padding: 3px 10px; border-radius: 4px;
}
.sev-crit  { background: rgba(220,38,38,.12); color: var(--a3); border: 1px solid rgba(220,38,38,.25); }
.sev-high  { background: rgba(245,158,11,.12);  color: #f59e0b; border: 1px solid rgba(245,158,11,.25); }
.sev-med   { background: rgba(180,83,9,.12); color: var(--a); border: 1px solid rgba(180,83,9,.25); }
.sev-low   { background: rgba(15,118,110,.1);    color: var(--a2); border: 1px solid rgba(15,118,110,.2); }

.bug-steps { list-style: none; padding: 0; margin: 0; }
.bug-steps li {
  padding: 4px 0;
  font-family: var(--fm);
  font-size: 12.5px;
  color: var(--t2);
  display: flex; gap: 10px;
}
.bug-steps li::before {
  content: attr(data-n);
  color: var(--a);
  font-size: 11px;
  min-width: 18px;
  font-weight: 600;
}

/* Test Case Table */
.tc-wrap {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  overflow: hidden;
}
.tc-tabs {
  display: flex;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
  overflow-x: auto;
}
.tc-tab {
  padding: 13px 20px;
  font-family: var(--fm);
  font-size: 12px;
  color: var(--t3);
  cursor: pointer;
  border: none;
  background: transparent;
  white-space: nowrap;
  border-bottom: 2px solid transparent;
  transition: all .2s;
}
.tc-tab:hover { color: var(--t2); }
.tc-tab.active { color: var(--a); border-bottom-color: var(--a); }
.tc-panel { display: none; padding: 0; }
.tc-panel.active { display: block; }
.tc-table { width: 100%; border-collapse: collapse; font-size: 13px; }
.tc-table th {
  padding: 10px 16px;
  font-family: var(--fm);
  font-size: 10.5px;
  color: var(--t3);
  font-weight: 400;
  border-bottom: 1px solid var(--border);
  text-align: left;
  background: var(--bg);
  white-space: nowrap;
}
.tc-table td {
  padding: 12px 16px;
  color: var(--t2);
  border-bottom: 1px solid var(--border);
  vertical-align: top;
  line-height: 1.55;
}
.tc-table tr:last-child td { border-bottom: none; }
.tc-table tr:hover td { background: rgba(255,255,255,.015); color: var(--t); }
.tc-id    { font-family: var(--fm); font-size: 11px; color: var(--t3); white-space: nowrap; }
.tc-pass  { background: rgba(15,118,110,.1);   color: var(--a2); font-family: var(--fm); font-size: 10px; padding: 2px 8px; border-radius: 4px; display: inline-block; }
.tc-fail  { background: rgba(220,38,38,.1); color: var(--a3); font-family: var(--fm); font-size: 10px; padding: 2px 8px; border-radius: 4px; display: inline-block; }
.tc-ntc   { background: rgba(180,83,9,.1); color: var(--a);  font-family: var(--fm); font-size: 10px; padding: 2px 8px; border-radius: 4px; display: inline-block; }
@media(max-width:860px){
  .bug-row { grid-template-columns: 1fr; }
  .bug-label { padding-top: 12px; padding-bottom: 0; }
  .bb-grid { grid-template-columns: 1fr; }
}