/* ============================================================
   אלקטרוניקה — עיצוב ראשי
   ============================================================ */

:root{
  --bg:            #eef2f7;
  --bg-grad:       radial-gradient(1200px 600px at 85% -10%, #dbe7ff 0%, transparent 60%),
                   radial-gradient(900px 500px at 0% 0%, #e6fbf4 0%, transparent 55%);
  --surface:       #ffffff;
  --surface-2:     #f7f9fc;
  --surface-3:     #eef2f8;
  --border:        #d9e1ec;
  --border-strong: #bcc9db;
  --text:          #16202e;
  --text-dim:      #5a6a80;
  --text-faint:    #8494a8;

  --primary:       #2563eb;
  --primary-dark:  #1d4ed8;
  --primary-soft:  #e5edff;
  --accent:        #0d9488;
  --accent-soft:   #d7f5f0;
  --warn:          #b45309;
  --warn-soft:     #fdf0d8;
  --danger:        #dc2626;
  --danger-soft:   #fde8e8;
  --ok:            #15803d;
  --ok-soft:       #dcf5e4;
  --challenge:     #c026d3;
  --challenge-soft:#fae4ff;

  --wire:          #1f2937;
  --wire-2:        #2563eb;

  --radius:        14px;
  --radius-sm:     9px;
  --shadow:        0 1px 2px rgba(16,32,58,.05), 0 8px 24px -12px rgba(16,32,58,.22);
  --shadow-lg:     0 24px 60px -20px rgba(16,32,58,.38);
  --font:          "Segoe UI", "Rubik", "Assistant", "Arial Hebrew", system-ui, sans-serif;
  --mono:          "JetBrains Mono", "Consolas", "Courier New", monospace;
}

/* ערכת נושא כהה — שלושה מצבים: בחירת המשתמש, בחירת הדפדפן/המארח, וברירת המחדל */
:root[data-theme="dark"]{
  --bg:            #0d1420;
  --bg-grad:       radial-gradient(1200px 600px at 85% -10%, #16273f 0%, transparent 60%),
                   radial-gradient(900px 500px at 0% 0%, #102a26 0%, transparent 55%);
  --surface:       #141d2c;
  --surface-2:     #1a2434;
  --surface-3:     #212d40;
  --border:        #2a374b;
  --border-strong: #3b4a63;
  --text:          #e6edf6;
  --text-dim:      #a2b1c6;
  --text-faint:    #7787a0;

  --primary:       #5b93ff;
  --primary-dark:  #3b7dff;
  --primary-soft:  #1b2a48;
  --accent:        #2dd4bf;
  --accent-soft:   #10312e;
  --warn:          #fbbf24;
  --warn-soft:     #33280e;
  --danger:        #f87171;
  --danger-soft:   #3a1a1a;
  --ok:            #4ade80;
  --ok-soft:       #10301c;
  --challenge:     #e879f9;
  --challenge-soft:#331436;

  --wire:          #cbd5e1;
  --wire-2:        #7dd3fc;
  --shadow:        0 1px 2px rgba(0,0,0,.4), 0 10px 28px -14px rgba(0,0,0,.7);
  --shadow-lg:     0 24px 60px -20px rgba(0,0,0,.75);
}

@media (prefers-color-scheme: dark){
  :root:not([data-theme="light"]){
    --bg:            #0d1420;
    --bg-grad:       radial-gradient(1200px 600px at 85% -10%, #16273f 0%, transparent 60%),
                     radial-gradient(900px 500px at 0% 0%, #102a26 0%, transparent 55%);
    --surface:       #141d2c;
    --surface-2:     #1a2434;
    --surface-3:     #212d40;
    --border:        #2a374b;
    --border-strong: #3b4a63;
    --text:          #e6edf6;
    --text-dim:      #a2b1c6;
    --text-faint:    #7787a0;

    --primary:       #5b93ff;
    --primary-dark:  #3b7dff;
    --primary-soft:  #1b2a48;
    --accent:        #2dd4bf;
    --accent-soft:   #10312e;
    --warn:          #fbbf24;
    --warn-soft:     #33280e;
    --danger:        #f87171;
    --danger-soft:   #3a1a1a;
    --ok:            #4ade80;
    --ok-soft:       #10301c;
    --challenge:     #e879f9;
    --challenge-soft:#331436;

    --wire:          #cbd5e1;
    --wire-2:        #7dd3fc;
    --shadow:        0 1px 2px rgba(0,0,0,.4), 0 10px 28px -14px rgba(0,0,0,.7);
    --shadow-lg:     0 24px 60px -20px rgba(0,0,0,.75);
  }
}

*{box-sizing:border-box}
html,body{margin:0;padding:0}
body{
  font-family:var(--font);
  background:var(--bg);
  background-image:var(--bg-grad);
  background-attachment:fixed;
  color:var(--text);
  line-height:1.65;
  -webkit-font-smoothing:antialiased;
}
h1,h2,h3,h4{line-height:1.3;margin:0 0 .5em}
p{margin:0 0 .8em}
a{color:var(--primary)}
button{font-family:inherit}

/* ---------- סרגל עליון ---------- */
.topbar{
  position:sticky;top:0;z-index:60;
  display:flex;align-items:center;gap:14px;
  padding:10px 18px;
  background:color-mix(in srgb, var(--surface) 88%, transparent);
  backdrop-filter:blur(14px);
  border-bottom:1px solid var(--border);
}
.brand{display:flex;align-items:center;gap:10px;min-width:0}
.brand-mark{
  font-size:22px;width:40px;height:40px;flex:none;
  display:grid;place-items:center;border-radius:12px;
  background:linear-gradient(140deg,var(--primary),var(--accent));
  box-shadow:0 6px 16px -6px var(--primary);
}
.brand-text{display:flex;flex-direction:column;line-height:1.15;min-width:0}
.brand-text strong{font-size:19px;letter-spacing:.2px}
.brand-text small{color:var(--text-dim);font-size:11.5px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.topbar-actions{margin-inline-start:auto;display:flex;gap:8px;align-items:center;flex-wrap:wrap}

.pill{
  border:1px solid var(--border-strong);
  background:var(--surface-2);color:var(--text);
  padding:7px 13px;border-radius:999px;font-size:13.5px;font-weight:600;
  cursor:pointer;transition:.16s;white-space:nowrap;
}
.pill:hover{background:var(--surface-3);transform:translateY(-1px)}
.pill:active{transform:translateY(0)}
.pill-accent{background:var(--primary-soft);border-color:transparent;color:var(--primary-dark)}
:root[data-theme="dark"] .pill-accent{color:var(--text)}
.pill-challenge{background:var(--challenge-soft);border-color:transparent;color:var(--challenge)}
.icon-btn{
  border:1px solid var(--border-strong);background:var(--surface-2);color:var(--text);
  width:38px;height:38px;border-radius:11px;font-size:17px;cursor:pointer;transition:.16s;
  display:grid;place-items:center;flex:none;
}
.icon-btn:hover{background:var(--surface-3)}
.menu-toggle{display:none}

/* ---------- פריסה ---------- */
.layout{display:flex;align-items:flex-start;gap:0}
.sidebar{
  position:sticky;top:59px;flex:none;width:268px;
  height:calc(100vh - 59px);overflow-y:auto;
  background:color-mix(in srgb, var(--surface) 70%, transparent);
  border-inline-start:1px solid var(--border);
  padding:14px 12px 20px;
  display:flex;flex-direction:column;gap:12px;
}
.side-search input{
  width:100%;padding:9px 12px;border-radius:10px;
  border:1px solid var(--border);background:var(--surface);color:var(--text);
  font-family:inherit;font-size:14px;
}
.side-search input:focus{outline:2px solid var(--primary);outline-offset:1px}
.nav-list{list-style:none;margin:0;padding:0;flex:1}
.nav-group{margin-bottom:6px}
.nav-group-title{
  font-size:11.5px;font-weight:800;letter-spacing:.5px;text-transform:uppercase;
  color:var(--text-faint);padding:10px 10px 4px;
}
.nav-item{
  display:flex;align-items:center;gap:9px;
  padding:8px 11px;border-radius:10px;cursor:pointer;
  font-size:14.5px;color:var(--text-dim);transition:.14s;user-select:none;
}
.nav-item:hover{background:var(--surface-3);color:var(--text)}
.nav-item.active{background:var(--primary);color:#fff;font-weight:700;box-shadow:0 6px 16px -8px var(--primary)}
.nav-item .ni-ico{font-size:15px;width:20px;text-align:center;flex:none}
.nav-item .ni-badge{
  margin-inline-start:auto;font-size:10.5px;font-weight:700;
  background:var(--surface-3);color:var(--text-faint);
  padding:1px 7px;border-radius:999px;
}
.nav-item.active .ni-badge{background:rgba(255,255,255,.25);color:#fff}
.side-foot{border-top:1px solid var(--border);padding-top:12px}
.progress-box{margin-bottom:10px}
.progress-label{font-size:12px;color:var(--text-dim);margin-bottom:5px}
.progress-track{height:7px;background:var(--surface-3);border-radius:99px;overflow:hidden}
.progress-fill{height:100%;width:0;background:linear-gradient(90deg,var(--accent),var(--primary));transition:width .4s}
.progress-num{font-size:11.5px;color:var(--text-faint);margin-top:4px;text-align:center}
.ghost-btn{
  width:100%;border:1px dashed var(--border-strong);background:none;color:var(--text-dim);
  padding:7px;border-radius:9px;font-size:12.5px;cursor:pointer;
}
.ghost-btn:hover{color:var(--danger);border-color:var(--danger)}
.scrim{display:none}

.content{flex:1;min-width:0;padding:26px 30px 90px;max-width:1180px;margin:0 auto}

/* ---------- כרטיסים ---------- */
.card{
  background:var(--surface);border:1px solid var(--border);
  border-radius:var(--radius);box-shadow:var(--shadow);
  padding:22px 24px;margin-bottom:20px;
}
.card-tight{padding:16px 18px}
.page-head{margin-bottom:22px}
.page-head h1{font-size:29px;margin-bottom:4px;letter-spacing:-.2px}
.page-head .sub{color:var(--text-dim);font-size:15px}
.kicker{
  display:inline-block;font-size:11.5px;font-weight:800;letter-spacing:.7px;
  text-transform:uppercase;color:var(--accent);margin-bottom:6px;
}

/* טאבים */
.tabs{display:flex;gap:6px;margin-bottom:18px;border-bottom:2px solid var(--border);flex-wrap:wrap}
.tab{
  border:none;background:none;color:var(--text-dim);
  padding:9px 16px;font-size:15px;font-weight:600;cursor:pointer;
  border-bottom:3px solid transparent;margin-bottom:-2px;transition:.15s;
}
.tab:hover{color:var(--text)}
.tab.active{color:var(--primary);border-bottom-color:var(--primary)}

/* ---------- סיכומים ---------- */
.summary-head{display:flex;align-items:flex-start;gap:12px;flex-wrap:wrap;margin-bottom:14px}
.summary-head h2{flex:1;min-width:200px;font-size:22px;margin:0}
.tts-group{display:flex;gap:6px}
.tts-btn.speaking{background:var(--ok-soft);border-color:var(--ok);color:var(--ok)}

.theory{font-size:15.5px}
.theory ul,.theory ol{padding-inline-start:22px;margin:0 0 .9em}
.theory li{margin-bottom:.35em}
.theory strong{color:var(--primary-dark)}
:root[data-theme="dark"] .theory strong{color:var(--primary)}

.note{
  border-inline-start:4px solid var(--primary);
  background:var(--primary-soft);
  padding:11px 15px;border-radius:0 var(--radius-sm) var(--radius-sm) 0;margin:14px 0;font-size:14.5px;
}
.note.warn{border-color:var(--warn);background:var(--warn-soft)}
.note.ok{border-color:var(--ok);background:var(--ok-soft)}
.note.danger{border-color:var(--danger);background:var(--danger-soft)}
.note b{display:block;margin-bottom:2px}

.formula-block{
  direction:ltr;text-align:center;
  background:var(--surface-2);border:1px solid var(--border);
  border-radius:var(--radius-sm);padding:14px 12px;margin:12px 0;
  overflow-x:auto;
}
.formula-block .fb-cap{
  direction:rtl;text-align:center;font-size:12.5px;color:var(--text-dim);margin-top:8px;
}
.formula-row{display:flex;gap:26px;justify-content:center;flex-wrap:wrap;align-items:center}

/* אלגוריתם פתרון */
.algo{counter-reset:algostep;list-style:none;padding:0;margin:6px 0}
.algo li{
  counter-increment:algostep;position:relative;
  padding:10px 46px 10px 12px;margin-bottom:8px;
  background:var(--surface-2);border:1px solid var(--border);border-radius:var(--radius-sm);
  font-size:14.8px;
}
.algo li::before{
  content:counter(algostep);
  position:absolute;inset-inline-start:10px;top:9px;
  width:26px;height:26px;border-radius:50%;
  background:var(--primary);color:#fff;font-weight:800;font-size:13px;
  display:grid;place-items:center;
}

/* ---------- שרטוטים ---------- */
.schematic{
  direction:ltr;text-align:center;margin:16px 0;
  background:var(--surface-2);border:1px solid var(--border);
  border-radius:var(--radius-sm);padding:14px 8px;overflow-x:auto;
}
.schematic svg{max-width:100%;height:auto}
.schematic .sch-cap{direction:rtl;font-size:12.5px;color:var(--text-dim);margin-top:6px}
.sch-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(210px,1fr));gap:12px}
.sch-grid .schematic{margin:0}

svg text{unicode-bidi:plaintext}
svg .wire{stroke:var(--wire);stroke-width:2;fill:none;stroke-linecap:round;stroke-linejoin:round}
svg .wire-thin{stroke:var(--wire);stroke-width:1.5;fill:none}
svg .comp{stroke:var(--wire);stroke-width:2;fill:none;stroke-linejoin:round}
svg .fillbg{fill:var(--surface-2)}
svg .node-dot{fill:var(--wire)}
svg .lbl{fill:var(--text);font-size:13px;font-family:var(--font)}
svg .lbl-sm{fill:var(--text-dim);font-size:11.5px;font-family:var(--font)}
svg .lbl-i{fill:var(--wire-2);font-size:12.5px;font-style:italic;font-family:var(--font)}
svg .cur{stroke:var(--wire-2);stroke-width:1.8;fill:none}
svg .cur-head{fill:var(--wire-2)}
svg .hl{stroke:var(--challenge);stroke-width:2;fill:none;stroke-dasharray:5 4}
svg .hl-txt{fill:var(--challenge);font-size:12px;font-weight:700}

/* ---------- תרגילים ---------- */
.ex-card{
  background:var(--surface);border:1px solid var(--border);
  border-radius:var(--radius);box-shadow:var(--shadow);margin-bottom:22px;overflow:hidden;
}
.ex-head{
  display:flex;align-items:center;gap:10px;flex-wrap:wrap;
  padding:14px 20px;border-bottom:1px solid var(--border);
  background:var(--surface-2);
}
.ex-head h3{margin:0;font-size:17.5px;flex:1;min-width:170px}
.tag{
  font-size:11px;font-weight:800;letter-spacing:.3px;padding:3px 9px;border-radius:999px;
  background:var(--surface-3);color:var(--text-dim);white-space:nowrap;
}
.tag-book{background:var(--accent-soft);color:var(--accent)}
.tag-challenge{background:var(--challenge-soft);color:var(--challenge)}
.tag-done{background:var(--ok-soft);color:var(--ok)}
.ex-body{padding:18px 20px}

.given{
  background:var(--surface-2);border:1px solid var(--border);border-radius:var(--radius-sm);
  padding:10px 14px;margin:10px 0 16px;font-size:14.5px;
}
.given b{color:var(--primary-dark)}
:root[data-theme="dark"] .given b{color:var(--primary)}

.parts{list-style:none;padding:0;margin:0}
.part{
  border:1px solid var(--border);border-radius:var(--radius-sm);
  padding:12px 14px;margin-bottom:11px;background:var(--surface-2);
}
.part-q{font-size:15px;margin-bottom:9px}
.part-q .pl{font-weight:800;color:var(--primary);margin-inline-end:5px}
.answer-row{display:flex;gap:8px;align-items:center;flex-wrap:wrap}
.answer-row input{
  flex:1;min-width:130px;padding:8px 11px;border-radius:9px;
  border:1px solid var(--border-strong);background:var(--surface);color:var(--text);
  font-family:var(--mono);font-size:14.5px;direction:ltr;text-align:left;
}
.answer-row input:focus{outline:2px solid var(--primary);outline-offset:1px}
.unit{color:var(--text-dim);font-size:13.5px;font-weight:700;min-width:26px}
.btn{
  border:none;border-radius:9px;padding:8px 15px;font-size:13.5px;font-weight:700;
  cursor:pointer;transition:.15s;white-space:nowrap;
}
.btn-primary{background:var(--primary);color:#fff}
.btn-primary:hover{background:var(--primary-dark)}
.btn-soft{background:var(--surface-3);color:var(--text);border:1px solid var(--border)}
.btn-soft:hover{background:var(--border)}
.btn-sm{padding:6px 11px;font-size:12.5px}

.fb{margin-top:9px;padding:10px 13px;border-radius:var(--radius-sm);font-size:14px;display:none}
.fb.show{display:block;animation:pop .22s ease}
@keyframes pop{from{opacity:0;transform:translateY(-4px)}to{opacity:1;transform:none}}
.fb-ok{background:var(--ok-soft);border:1px solid var(--ok);color:var(--ok)}
.fb-err{background:var(--danger-soft);border:1px solid var(--danger);color:var(--danger)}
.fb-warn{background:var(--warn-soft);border:1px solid var(--warn);color:var(--warn)}
.fb b{display:block;margin-bottom:3px}
.fb ul{margin:5px 0 0;padding-inline-start:20px}
.fb code{
  font-family:var(--mono);direction:ltr;display:inline-block;
  background:rgba(127,127,127,.16);padding:1px 5px;border-radius:5px;font-size:13px;
}

/* שלבי פתרון */
.steps-wrap{margin-top:18px;border-top:1px dashed var(--border-strong);padding-top:16px}
.steps-title{font-size:16px;font-weight:800;margin-bottom:4px;display:flex;align-items:center;gap:8px}
.steps-hint{font-size:13px;color:var(--text-dim);margin-bottom:12px}
.step{
  border:1px solid var(--border);border-inline-start:4px solid var(--border-strong);
  border-radius:var(--radius-sm);padding:12px 14px;margin-bottom:10px;background:var(--surface);
}
.step.done{border-inline-start-color:var(--ok);background:color-mix(in srgb,var(--ok-soft) 45%,var(--surface))}
.step-head{display:flex;gap:9px;align-items:flex-start;margin-bottom:8px}
.step-num{
  flex:none;width:25px;height:25px;border-radius:50%;background:var(--surface-3);
  color:var(--text-dim);font-weight:800;font-size:12.5px;display:grid;place-items:center;
}
.step.done .step-num{background:var(--ok);color:#fff}
.step-prompt{font-size:14.6px;flex:1}
.step-syntax{font-size:12px;color:var(--text-faint);margin-top:3px}
.step-syntax code{font-family:var(--mono);direction:ltr;display:inline-block}

/* רמזים */
.hint-bar{display:flex;gap:8px;flex-wrap:wrap;margin-top:16px;padding-top:14px;border-top:1px dashed var(--border-strong)}
.hint-box{
  margin-top:11px;border-radius:var(--radius-sm);padding:13px 16px;
  background:var(--warn-soft);border:1px solid var(--warn);font-size:14.5px;display:none;
}
.hint-box.show{display:block;animation:pop .22s ease}
.hint-box h4{margin:0 0 6px;font-size:14.5px;color:var(--warn);display:flex;gap:7px;align-items:center}
.hint-box ol,.hint-box ul{margin:6px 0 0;padding-inline-start:22px}
.hint-box li{margin-bottom:4px}
.hint-lvl-1{background:var(--primary-soft);border-color:var(--primary)}
.hint-lvl-1 h4{color:var(--primary-dark)}
:root[data-theme="dark"] .hint-lvl-1 h4{color:var(--primary)}
.hint-lvl-3{background:var(--challenge-soft);border-color:var(--challenge)}
.hint-lvl-3 h4{color:var(--challenge)}

.solution-box{
  margin-top:12px;border:1px solid var(--border);border-radius:var(--radius-sm);
  background:var(--surface-2);padding:14px 17px;display:none;font-size:14.6px;
}
.solution-box.show{display:block}
.solution-box h4{margin:0 0 8px;font-size:15px}
.sol-step{margin-bottom:10px;padding-inline-start:12px;border-inline-start:3px solid var(--accent)}
.sol-step .sl{font-weight:800;color:var(--accent);font-size:13px;display:block}

/* ---------- מודאלים ---------- */
.modal{
  position:fixed;inset:0;z-index:100;display:none;
  background:rgba(10,18,32,.55);backdrop-filter:blur(3px);
  padding:24px;overflow-y:auto;
}
.modal.open{display:flex;align-items:flex-start;justify-content:center}
.modal-card{
  background:var(--surface);border-radius:18px;box-shadow:var(--shadow-lg);
  width:100%;max-width:640px;margin:auto;animation:rise .22s ease;
  border:1px solid var(--border);
}
.modal-wide{max-width:980px}
@keyframes rise{from{opacity:0;transform:translateY(14px)}to{opacity:1;transform:none}}
.modal-head{
  display:flex;align-items:center;gap:12px;padding:16px 22px;
  border-bottom:1px solid var(--border);position:sticky;top:0;
  background:var(--surface);border-radius:18px 18px 0 0;z-index:2;flex-wrap:wrap;
}
.modal-head h2{margin:0;font-size:19px;flex:1;min-width:150px}
.modal-head-actions{display:flex;gap:7px;align-items:center}
.modal-body{padding:20px 22px 26px}

/* דף נוסחאות */
.fs-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(310px,1fr));gap:16px}
.fs-sec{border:1px solid var(--border);border-radius:var(--radius-sm);overflow:hidden;background:var(--surface-2)}
.fs-sec > h3{
  margin:0;padding:9px 14px;font-size:14.5px;
  background:var(--primary);color:#fff;display:flex;align-items:center;gap:7px;
}
.fs-sec.teal > h3{background:var(--accent)}
.fs-sec.purple > h3{background:var(--challenge)}
.fs-sec.amber > h3{background:var(--warn)}
.fs-sec-body{padding:12px 14px}
.fs-line{
  display:flex;gap:10px;align-items:center;justify-content:space-between;
  padding:7px 0;border-bottom:1px dashed var(--border);flex-wrap:wrap;
}
.fs-line:last-child{border-bottom:none}
.fs-name{font-size:13.4px;color:var(--text-dim);flex:1;min-width:110px}
.fs-math{direction:ltr;font-size:15px;flex:none}

/* מחשבון */
.calc-tabs{display:flex;gap:6px;margin-bottom:14px;flex-wrap:wrap}
.calc-tab{
  border:1px solid var(--border-strong);background:var(--surface-2);color:var(--text-dim);
  padding:6px 13px;border-radius:999px;font-size:13px;font-weight:700;cursor:pointer;
}
.calc-tab.active{background:var(--primary);border-color:var(--primary);color:#fff}
.keys{display:flex;flex-wrap:wrap;gap:6px;align-items:center;margin:6px 0 2px;direction:ltr;justify-content:flex-start}
.key{
  font-family:var(--mono);font-size:12.5px;font-weight:700;
  background:var(--surface-3);border:1px solid var(--border-strong);border-bottom-width:3px;
  border-radius:7px;padding:3px 9px;white-space:nowrap;
}
.key-arrow{color:var(--text-faint);font-size:14px}

/* אתגר */
.ch-opt{
  display:flex;gap:12px;align-items:flex-start;
  border:1px solid var(--border);border-radius:var(--radius-sm);
  padding:13px 15px;margin-bottom:10px;cursor:pointer;transition:.15s;background:var(--surface-2);
}
.ch-opt:hover{border-color:var(--challenge);background:var(--challenge-soft)}
.ch-opt .ch-ico{font-size:22px;flex:none}
.ch-opt h4{margin:0 0 2px;font-size:15px}
.ch-opt p{margin:0;font-size:13px;color:var(--text-dim)}

/* בית */
.hero{
  background:linear-gradient(135deg,var(--primary),var(--accent));
  color:#fff;border-radius:18px;padding:30px 32px;margin-bottom:24px;
  box-shadow:0 20px 50px -22px var(--primary);
}
.hero h1{font-size:31px;margin:0 0 8px;color:#fff}
.hero p{font-size:15.5px;opacity:.94;max-width:62ch;margin:0}
.hero-actions{display:flex;gap:10px;margin-top:18px;flex-wrap:wrap}
.hero-actions .pill{background:rgba(255,255,255,.18);border-color:rgba(255,255,255,.34);color:#fff}
.hero-actions .pill:hover{background:rgba(255,255,255,.3)}

.tiles{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:15px}
.tile{
  background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);
  padding:18px 20px;cursor:pointer;transition:.18s;box-shadow:var(--shadow);
}
.tile:hover{transform:translateY(-3px);border-color:var(--primary);box-shadow:0 16px 34px -18px var(--primary)}
.tile .t-ico{font-size:26px;margin-bottom:8px}
.tile h3{margin:0 0 4px;font-size:16.5px}
.tile p{margin:0;font-size:13.4px;color:var(--text-dim)}
.tile .t-meta{margin-top:10px;font-size:11.5px;color:var(--text-faint);display:flex;gap:8px;flex-wrap:wrap}

/* טוסט */
.toast{
  position:fixed;bottom:24px;inset-inline-start:50%;transform:translateX(50%) translateY(140%);
  background:var(--text);color:var(--surface);padding:11px 20px;border-radius:999px;
  font-size:14px;font-weight:600;z-index:200;transition:transform .3s;box-shadow:var(--shadow-lg);
  max-width:90vw;text-align:center;
}
.toast.show{transform:translateX(50%) translateY(0)}

/* עזר */
.muted{color:var(--text-dim)}
.small{font-size:13px}
.center{text-align:center}
.ltr{direction:ltr;display:inline-block}
.mono{font-family:var(--mono);direction:ltr;display:inline-block}
.chips{display:flex;gap:7px;flex-wrap:wrap;margin:8px 0}
.chip{font-size:12.5px;background:var(--surface-3);border:1px solid var(--border);padding:3px 10px;border-radius:999px}
.katex{font-size:1.06em}
.katex-display{margin:.5em 0 !important}
table.tbl{width:100%;border-collapse:collapse;margin:12px 0;font-size:14px}
table.tbl th,table.tbl td{border:1px solid var(--border);padding:7px 11px;text-align:start}
table.tbl th{background:var(--surface-3);font-weight:700}
table.tbl td.ltr{direction:ltr;text-align:left}

/* ---------- רספונסיבי ---------- */
@media (max-width: 1000px){
  .menu-toggle{display:grid}
  .sidebar{
    position:fixed;top:59px;right:0;left:auto;z-index:70;
    transform:translateX(110%);transition:transform .25s;
    background:var(--surface);width:280px;box-shadow:var(--shadow-lg);
    border-inline-start:1px solid var(--border);
  }
  .sidebar.open{transform:none}
  .scrim{display:block;position:fixed;inset:59px 0 0;background:rgba(8,14,24,.5);z-index:65;opacity:0;pointer-events:none;transition:.25s}
  .scrim.open{opacity:1;pointer-events:auto}
  .content{padding:20px 16px 80px}
  .brand-text small{display:none}
}
@media (max-width: 640px){
  .topbar{padding:8px 11px;gap:8px}
  .topbar-actions .pill{padding:6px 10px;font-size:12.5px}
  .hero{padding:22px 18px}
  .hero h1{font-size:24px}
  .card{padding:16px 15px}
  .ex-body,.ex-head{padding:13px 14px}
  .modal{padding:10px}
  .modal-body{padding:16px 14px 22px}
  .modal-head{padding:13px 15px}
  .answer-row input{min-width:100px}
}

@media print{
  .topbar,.sidebar,.hint-bar,.steps-wrap,.answer-row,.scrim{display:none !important}
  .content{padding:0;max-width:none}
  .card,.ex-card{box-shadow:none;break-inside:avoid}
}

/* ============================================================
   הורדות — דפי עזר כקובצי PDF
   ============================================================ */
.pill-dl{background:var(--ok-soft);border-color:transparent;color:var(--ok)}
.tag-practice{background:var(--primary-soft);color:var(--primary-dark)}
:root[data-theme="dark"] .tag-practice{color:var(--primary)}
.tag-lvl-easy{background:var(--ok-soft);color:var(--ok)}
.tag-lvl-mid{background:var(--warn-soft);color:var(--warn)}
.tag-lvl-hard{background:var(--danger-soft);color:var(--danger)}

.dl-bar{
  display:flex;align-items:center;gap:10px;flex-wrap:wrap;
  background:var(--surface);border:1px solid var(--border);border-inline-start:4px solid var(--ok);
  border-radius:var(--radius);padding:11px 16px;margin-bottom:16px;box-shadow:var(--shadow);
}
.dl-txt{flex:1;min-width:190px;display:flex;flex-direction:column;line-height:1.35}
.dl-txt b{font-size:14.5px}
.btn-dl{text-decoration:none;display:inline-flex;align-items:center;gap:5px}
a.btn{text-decoration:none}

.dl-hero{display:flex;align-items:center;gap:20px;flex-wrap:wrap;
  background:linear-gradient(135deg,var(--primary),var(--accent));color:#fff;border:0}
.dl-hero .kicker,.dl-hero h2,.dl-hero .muted{color:#fff}
.dl-hero .muted{opacity:.92}
.dl-hero > div:first-child{flex:1;min-width:260px}
.dl-hero .btn-soft{background:rgba(255,255,255,.2);border-color:rgba(255,255,255,.4);color:#fff}
.dl-hero .btn-primary{background:#fff;color:var(--primary-dark)}
.dl-book{font-size:72px;line-height:1;flex:none}
.dl-row{display:flex;gap:8px;flex-wrap:wrap}

.dl-group{font-size:17px;margin:22px 0 10px;padding-bottom:4px;border-bottom:2px solid var(--border)}
.dl-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(268px,1fr));gap:12px}
.dl-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);
  padding:14px 16px;box-shadow:var(--shadow);display:flex;flex-direction:column;gap:10px}
.dl-card-top{display:flex;gap:10px;align-items:flex-start}
.dl-card h3{margin:0;font-size:15px;line-height:1.3}
.dl-ico{font-size:22px;flex:none}

@media (max-width:640px){
  .dl-bar{padding:10px 12px}
  .dl-hero{padding:18px 16px}
  .dl-book{font-size:48px}
}

/* ============================================================
   גרפים ואופייני מעבר (plot.js) — באתר
   ============================================================ */
:root{ --sig-in:#2563eb; --sig-out:#c2410c; --p-grid:#d6dee8; }
:root[data-theme="dark"]{ --sig-in:#7dd3fc; --sig-out:#fb923c; --p-grid:#2a374b; }
@media (prefers-color-scheme: dark){
  :root:not([data-theme="light"]){ --sig-in:#7dd3fc; --sig-out:#fb923c; --p-grid:#2a374b; }
}
svg .p-grid{stroke:var(--p-grid);stroke-width:.8}
svg .p-axis{stroke:var(--text);stroke-width:1.2;fill:none}
svg .p-ah{fill:var(--text)}
svg .p-in{fill:none;stroke:var(--sig-in);stroke-width:2.2;stroke-linejoin:round;stroke-linecap:round}
svg .p-out{fill:none;stroke:var(--sig-out);stroke-width:2.6;stroke-linejoin:round;stroke-linecap:round}
svg .p-outhead{fill:var(--sig-out)}
svg .p-inhead{fill:var(--sig-in)}
svg .p-th{stroke:var(--text-dim);stroke-width:1;stroke-dasharray:5 3;fill:none}
svg .p-drop{stroke:var(--text-faint);stroke-width:.9;stroke-dasharray:2 2.5;fill:none}
svg .p-dot{fill:var(--sig-in)}
svg .p-t{fill:var(--text);font:500 12px var(--mono)}
svg .p-t.sm{font-size:10.5px}
svg .p-t.b{font-weight:700}
svg .p-t.acc{fill:var(--accent)}
svg .p-halo{paint-order:stroke;stroke:var(--surface);stroke-width:4px;stroke-linejoin:round}
svg .p-meas{stroke:var(--accent);stroke-width:1.3;fill:none}
svg .p-meashead{fill:var(--accent)}
svg .p-brace{stroke:var(--accent);stroke-width:1.3;fill:none}


/* ============================================================
   פיתוח בשלושה שלבים: נוסחה ← סימני המעגל ← הצבה
   ============================================================ */
.derive{display:grid;grid-template-columns:auto minmax(0,1fr);gap:4px 10px;
  align-items:baseline;margin:8px 0 10px}
.derive > .dl{font-size:11px;font-weight:800;letter-spacing:.03em;color:#fff;
  background:var(--primary);border-radius:5px;padding:1px 8px;white-space:nowrap;
  justify-self:start;align-self:center}
.derive > .dl.n{background:var(--ok)}
.derive > div{min-width:0}