:root{
  --bg:#0f1220; --bg2:#161a2e; --card:#1a2038; --card2:#202642;
  --accent:#6d8bff; --accent2:#9b6dff; --green:#3ddc97; --red:#ff5d5d;
  --text:#e8eaf2; --muted:#9aa0b8; --border:#2a3152;
  --mono:'JetBrains Mono',monospace; --sans:'Inter',system-ui,sans-serif;
}
*{box-sizing:border-box;margin:0;padding:0}
body{background:var(--bg);color:var(--text);font-family:var(--sans);line-height:1.6}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}

/* Topbar */
.topbar{display:flex;align-items:center;justify-content:space-between;padding:16px 28px;background:#11142a;border-bottom:1px solid var(--border);flex-wrap:wrap;gap:12px}
.brand{font-size:20px;font-weight:800;color:var(--text)}
.brand-accent{color:var(--accent)}
.nav{display:flex;align-items:center;gap:18px;flex-wrap:wrap}
.nav a{color:var(--muted);font-weight:500;font-size:14px}
.nav a:hover{color:var(--text);text-decoration:none}
.admin-link{color:var(--accent2)!important}

/* Buttons */
.btn{display:inline-block;padding:10px 18px;border-radius:10px;font-weight:600;border:none;cursor:pointer;font-family:var(--sans);font-size:14px;transition:.2s;text-decoration:none}
.btn:hover{text-decoration:none;transform:translateY(-1px)}
.btn-primary{background:linear-gradient(135deg,var(--accent),var(--accent2));color:#fff}
.btn-ghost{background:transparent;color:var(--text);border:1px solid var(--border)}
.btn-ghost:hover{border-color:var(--accent)}
.btn-danger{background:rgba(255,93,93,.15);color:var(--red);border:1px solid var(--red)}
.btn-lg{padding:14px 26px;font-size:16px}
.btn-sm{padding:7px 14px;font-size:13px}
.btn-xs{padding:4px 10px;font-size:12px}
.btn-block{width:100%}

/* Flash */
.flash-wrap{max-width:1000px;margin:14px auto;padding:0 20px}
.flash{padding:12px 16px;border-radius:10px;margin-bottom:10px;font-size:14px}
.flash-success{background:rgba(61,220,151,.12);border:1px solid var(--green);color:var(--green)}
.flash-danger{background:rgba(255,93,93,.12);border:1px solid var(--red);color:var(--red)}
.flash-warning{background:rgba(255,200,90,.12);border:1px solid #ffc85a;color:#ffc85a}
.flash-info{background:var(--card);border:1px solid var(--border)}

.container{max-width:1000px;margin:0 auto;padding:28px 20px;min-height:70vh}

/* Hero */
.hero{display:grid;grid-template-columns:1.2fr 1fr;gap:40px;align-items:center;margin-bottom:50px}
.hero h1{font-size:40px;line-height:1.15;margin-bottom:18px}
.accent{color:var(--accent)}
.hero p{color:var(--muted);font-size:17px;margin-bottom:24px}
.hero-actions{display:flex;gap:12px;flex-wrap:wrap}
.code-card{background:var(--card);border:1px solid var(--border);border-radius:14px;padding:18px}
.code-dots{display:flex;gap:8px;margin-bottom:14px}
.code-dots span{width:12px;height:12px;border-radius:50%;background:#ff5f57}
.code-dots span:nth-child(2){background:#febc2e}
.code-dots span:nth-child(3){background:#28c840}
.code-card pre{font-family:var(--mono);font-size:15px;color:#9bd8ff;white-space:pre-wrap}

/* Features */
.features{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}
.feature-card{background:var(--card);border:1px solid var(--border);border-radius:14px;padding:24px}
.feature-icon{font-size:30px;margin-bottom:10px}
.feature-card h3{margin-bottom:8px}
.feature-card p{color:var(--muted);font-size:14px}

/* Page head */
.page-head{margin-bottom:24px}
.page-head h1{font-size:30px;margin-bottom:6px}
.muted{color:var(--muted)}
.center{text-align:center;margin-top:12px}

/* Lessons */
.lesson-list{display:flex;flex-direction:column;gap:10px}
.lesson-item{display:flex;align-items:center;gap:16px;background:var(--card);border:1px solid var(--border);border-radius:12px;padding:14px 18px;transition:.15s}
.lesson-item:hover{background:var(--card2);text-decoration:none;transform:translateX(3px)}
.lesson-num{width:34px;height:34px;border-radius:50%;background:linear-gradient(135deg,var(--accent),var(--accent2));display:flex;align-items:center;justify-content:center;font-weight:700;color:#fff;flex-shrink:0}
.lesson-body{flex:1;display:flex;flex-direction:column}
.lesson-title{font-weight:600}
.lesson-cat{color:var(--muted);font-size:12px;text-transform:capitalize}
.badge{padding:5px 12px;border-radius:20px;font-size:12px;font-weight:600;background:var(--bg2);border:1px solid var(--border);flex-shrink:0}
.badge-done{background:rgba(61,220,151,.15);color:var(--green);border-color:var(--green)}

/* Lesson page */
.back-link{color:var(--muted);font-size:14px;display:inline-block;margin-bottom:16px}
.lesson-page{background:var(--card);border:1px solid var(--border);border-radius:14px;padding:28px}
.lesson-page h1{margin-bottom:8px}
.chip{background:var(--bg2);border:1px solid var(--border);padding:4px 12px;border-radius:20px;font-size:12px;text-transform:capitalize;display:inline-block;margin-bottom:16px}
.markdown{font-size:16px;margin-bottom:20px}
.quick-box{background:rgba(109,139,255,.08);border:1px solid var(--accent);border-radius:12px;padding:14px;margin-top:20px;font-size:14px}

/* Auth */
.auth-card{max-width:420px;margin:30px auto;background:var(--card);border:1px solid var(--border);border-radius:16px;padding:32px}
.auth-card h2{margin-bottom:6px}
.form{display:flex;flex-direction:column;gap:16px;margin-top:18px}
.form label{display:flex;flex-direction:column;gap:6px;font-size:14px;font-weight:500;color:var(--muted)}
.form input,.form select,.form textarea{background:var(--bg2);border:1px solid var(--border);border-radius:10px;padding:12px;color:var(--text);font-family:var(--sans);font-size:15px}
.form input:focus,.form textarea:focus{outline:none;border-color:var(--accent)}

/* AI grid */
.ai-grid{display:grid;grid-template-columns:1fr 1fr;gap:20px}
.panel{background:var(--card);border:1px solid var(--border);border-radius:14px;padding:22px}
.panel h3{margin-bottom:14px}
.field-label{font-size:13px;font-weight:600;color:var(--muted);display:block;margin-bottom:8px}
.code-input{width:100%;background:#0b0e1f;border:1px solid var(--border);border-radius:10px;padding:14px;color:#c7f9cc;font-family:var(--mono);font-size:14px;line-height:1.5;min-height:120px}
.code-input:focus{outline:none;border-color:var(--accent)}
.row-gap{display:flex;gap:12px;margin-top:14px;flex-wrap:wrap}
.row-gap-sm{display:flex;gap:6px;align-items:center}
.output-box{background:var(--bg2);border:1px solid var(--border);border-radius:10px;padding:16px;min-height:200px;max-height:480px;overflow:auto;font-size:14px}
.explain-text{white-space:pre-wrap}
.error{color:var(--red)}
.loading{color:var(--accent);margin-top:10px;font-size:14px}
.hidden{display:none}

/* Compare */
.compare-output{margin:20px 0}
.style-row{display:grid;grid-template-columns:1fr 1fr;gap:16px}
.style-col h3{margin:0 0 10px;font-size:16px}
.code-block{background:#0b0e1f;border:1px solid var(--border);border-radius:10px;padding:16px;font-family:var(--mono);font-size:13px;overflow-x:auto;white-space:pre;color:#9bd8ff}
.compare-note{background:var(--card2);border:1px solid var(--border);border-radius:10px;padding:12px 16px;margin-bottom:16px;font-size:14px}
.snippet-list{display:flex;gap:8px;flex-wrap:wrap}
.snippet-btn{background:var(--bg2);border:1px solid var(--border);border-radius:8px;padding:6px 12px;font-size:12px;color:var(--muted);cursor:pointer}
.snippet-btn:hover{border-color:var(--accent);color:var(--text)}

/* Dashboard */
.stats{margin-bottom:20px}
.stat-card{background:var(--card);border:1px solid var(--border);border-radius:14px;padding:22px;max-width:360px}
.stat-value{font-size:34px;font-weight:800;color:var(--accent)}
.stat-label{color:var(--muted);font-size:14px;margin-bottom:10px}
.progress{height:10px;background:var(--bg2);border-radius:20px;overflow:hidden}
.progress-bar{height:100%;background:linear-gradient(135deg,var(--accent),var(--green));border-radius:20px}
.grid-2{display:grid;grid-template-columns:1fr 1fr;gap:20px}
.plain-list{list-style:none}
.plain-list li{padding:6px 0;border-bottom:1px solid var(--border)}
.tool-links{display:flex;flex-direction:column;gap:10px}
.tool-link{background:var(--bg2);border:1px solid var(--border);border-radius:10px;padding:12px 14px;font-weight:600;color:var(--text)}
.tool-link:hover{text-decoration:none;border-color:var(--accent)}

/* Admin */
.admin-grid{display:grid;grid-template-columns:1fr 1fr;gap:20px;align-items:start}
.table{width:100%;border-collapse:collapse;font-size:14px}
.table th,.table td{padding:10px;border-bottom:1px solid var(--border);text-align:left;vertical-align:middle}
.table th{color:var(--muted);font-size:12px;text-transform:uppercase;letter-spacing:.5px}

/* Footer */
.footer{border-top:1px solid var(--border);padding:24px;text-align:center;color:var(--muted);font-size:13px}

@media (max-width:820px){
  .hero,.ai-grid,.style-row,.grid-2,.admin-grid{grid-template-columns:1fr}
  .hero h1{font-size:30px}
  .features{grid-template-columns:1fr}
}

/* Playground */
.pg-layout{display:grid;grid-template-columns:1fr 1fr;gap:18px;margin:18px 0}
@media(max-width:760px){.pg-layout{grid-template-columns:1fr}}
.pg-toolbar{display:flex;align-items:center;gap:12px;justify-content:space-between;margin-bottom:10px}
.pg-status{font-size:12px;color:var(--green);font-family:var(--mono)}
.pg-err{color:var(--red);white-space:pre-wrap}
.mono{font-family:var(--mono)}

/* Quiz */
.quiz-q{margin-bottom:14px}
.quiz-text{font-size:17px;margin-bottom:12px}
.quiz-opts{display:grid;gap:8px}
.quiz-opt{display:flex;align-items:center;gap:10px;padding:10px 14px;border:1px solid var(--border);border-radius:10px;cursor:pointer;background:var(--card2);transition:.15s}
.quiz-opt:hover{border-color:var(--accent)}
.quiz-opt input{margin:0}
.quiz-actions{margin:18px 0}
.quiz-detail{padding:10px 0;border-bottom:1px solid var(--border)}
.green-text{color:var(--green)}
.red-text{color:var(--red)}
.small{font-size:13px}

.badge-admin{background:rgba(250,204,21,.15);color:#facc15;border-color:#facc15}
.badge-student{background:rgba(96,165,250,.15);color:#60a5fa;border-color:#60a5fa}
.panel-head{display:flex;justify-content:space-between;align-items:center;gap:1rem;flex-wrap:wrap}
.table-wrap{overflow-x:auto}
.panel .table{width:100%}
.panel .table th,.panel .table td{padding:8px 10px;text-align:left;border-bottom:1px solid var(--border);white-space:nowrap}
.panel .table th{font-size:12px;text-transform:uppercase;letter-spacing:.05em;color:var(--muted)}

/* Phone row: country code + number */
.phone-row{display:flex;gap:8px;align-items:stretch}
.phone-row select{flex:0 0 auto;max-width:180px;padding:10px 8px;border:1px solid var(--border);border-radius:8px;background:var(--bg2);color:var(--text);font-size:14px}
.phone-row input{flex:1 1 auto;min-width:0}
.hint{display:block;font-size:12px;color:var(--muted);margin-top:4px}

/* Code Review platform */
.review-link{color:#f472b6;font-weight:600}
.upload-row{display:flex;align-items:center;gap:10px;margin:10px 0}
.file-btn{display:inline-block;cursor:pointer}
.review-verdict{display:flex;align-items:center;gap:12px;flex-wrap:wrap;margin-bottom:6px}
.review-score{font-size:26px;font-weight:800;color:var(--text)}
.review-h{margin:14px 0 6px;font-size:14px;text-transform:uppercase;letter-spacing:.04em;color:var(--muted)}
.cat-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:10px}
.cat-top{display:flex;justify-content:space-between;font-size:13px;margin-bottom:3px}
.cat-top b{color:var(--text)}
.cat .progress{height:6px}
.algo code{background:var(--bg2);padding:2px 8px;border-radius:6px;border:1px solid var(--border)}
.badge-warn{background:rgba(250,204,21,.15);color:#facc15;border-color:#facc15}
.badge-danger{background:rgba(239,68,68,.15);color:#ef4444;border-color:#ef4444}

/* Membership & pricing */
.upgrade-link{color:#facc15;font-weight:700}
.member-card{border:1px solid rgba(250,204,21,.4);background:linear-gradient(135deg,rgba(250,204,21,.06),rgba(244,114,182,.05))}
.member-head{display:flex;align-items:center;gap:12px;flex-wrap:wrap}
.pricing-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:1.25rem;margin-top:1rem}
.pricing-card{display:flex;flex-direction:column;gap:.75rem}
.pricing-card.featured{border:2px solid rgba(250,204,21,.5);position:relative}
.pricing-card .price{font-size:30px;font-weight:800;color:var(--text)}
.pricing-card .price .muted{font-size:13px;font-weight:400}
.trial-limit{text-align:center;padding:2rem 1rem;border:1px dashed var(--border);border-radius:12px}
.trial-limit h3{margin-bottom:.5rem}
.inline-form{display:inline-flex;gap:6px;align-items:center}
.input-xs{padding:4px 6px;font-size:12px;border:1px solid var(--border);border-radius:6px;background:var(--bg2);color:var(--text);max-width:130px}

/* Bank transfer details */
.bank-details{background:rgba(52,211,153,.06);border:1px dashed var(--accent);border-radius:12px;padding:14px 18px;margin:14px 0;display:grid;grid-template-columns:1fr 1fr;gap:6px 18px}
.bank-details p{margin:0;font-size:14px}
@media(max-width:560px){.bank-details{grid-template-columns:1fr}}

/* Membership popup modal */
.modal-overlay{position:fixed;inset:0;background:rgba(4,6,15,.72);display:none;align-items:center;justify-content:center;z-index:1000;padding:1rem}
.modal{background:var(--card2);max-width:500px;width:100%;border-radius:18px;padding:1.9rem;box-shadow:0 24px 70px rgba(0,0,0,.5);position:relative;border:1px solid var(--border);animation:pop .25s ease}
@keyframes pop{from{transform:scale(.92);opacity:0}to{transform:scale(1);opacity:1}}
.modal-close{position:absolute;top:.85rem;right:1rem;background:none;border:none;font-size:1.15rem;cursor:pointer;color:var(--muted)}
.modal-close:hover{color:var(--text)}
.modal h2{margin:0 0 .4rem;font-size:1.35rem}
.modal-plans{display:grid;grid-template-columns:1fr 1fr;gap:.8rem;margin:1.1rem 0}
.modal-plan{border:1px solid var(--border);border-radius:14px;padding:1rem;text-align:center;background:var(--card)}
.modal-plan.featured{border-color:#f59e0b;background:linear-gradient(180deg,#2a2410,#1d2138)}
.modal-price{font-size:1.5rem;font-weight:800;color:var(--text)}
.modal-price span{font-size:.85rem;font-weight:500;color:var(--muted)}
.modal-price em{display:block;font-size:.75rem;font-style:normal;color:#fbbf24;margin-top:.15rem}
.center{text-align:center}

.lesson-locked{opacity:.62;cursor:not-allowed}
.lesson-locked .lesson-title{color:var(--muted)}
.checkbox-row{display:flex;align-items:center;gap:.5rem;margin:1rem 0;font-weight:600}