:root{
  --crust:#0c0a08;--base:#111009;--surface:#161310;--card:#1c1814;--card2:#231e19;
  --ember:#e07b35;--ember-dim:rgba(224,123,53,.12);--ember-border:rgba(224,123,53,.22);
  --sand:#ede0cc;--sand2:#c4b49e;--fog:#7a6a58;--muted:#3d3028;
  --green:#3ecf6e;--blue:#4a9eff;--red:#e05252;--yellow:#f5c842;
  --border:rgba(255,255,255,.06);--border2:rgba(255,255,255,.1);
  --font:'DM Sans',system-ui,sans-serif;
  --head:'Syne',system-ui,sans-serif;
  --mono:'JetBrains Mono',monospace;
  --r:14px;--r-sm:10px;--r-xs:8px;
  --ease:cubic-bezier(.4,0,.2,1);
  --shadow:0 8px 32px rgba(0,0,0,.45);
}
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0;}
html{scroll-behavior:smooth;}
body{font-family:var(--font);background:var(--crust);color:var(--sand);min-height:100vh;
  background-image:radial-gradient(ellipse 70% 30% at 50% 0%,rgba(224,123,53,.05),transparent);}

/* ── TOPBAR ── */
.topbar{position:sticky;top:0;z-index:100;height:56px;
  background:rgba(12,10,8,.88);backdrop-filter:blur(20px);-webkit-backdrop-filter:blur(20px);
  border-bottom:1px solid var(--border);display:flex;align-items:center;gap:0;padding:0 16px;}
.topbar-logo{font-family:var(--head);font-weight:800;font-size:1.1rem;color:var(--sand);
  text-decoration:none;display:flex;align-items:center;gap:6px;flex-shrink:0;}
.topbar-logo .dot{color:var(--ember);}
.topbar-sep{width:1px;height:22px;background:var(--border);margin:0 14px;}
.topbar-title{font-family:var(--head);font-size:.95rem;font-weight:700;color:var(--sand2);}
.topbar-right{margin-left:auto;display:flex;align-items:center;gap:8px;}
.topbar-btn{display:flex;align-items:center;gap:6px;padding:7px 14px;border-radius:var(--r-sm);
  border:1px solid var(--border2);background:rgba(255,255,255,.04);color:var(--sand2);
  font-size:.8rem;font-family:var(--font);cursor:pointer;text-decoration:none;transition:all .2s;}
.topbar-btn:hover{border-color:var(--ember-border);color:var(--ember);}
.topbar-btn.primary{background:linear-gradient(135deg,#c96820,var(--ember));
  border-color:transparent;color:#0c0a08;font-weight:700;}
.topbar-btn.primary:hover{transform:translateY(-1px);box-shadow:0 4px 16px rgba(224,123,53,.3);}
.topbar-back{width:36px;height:36px;border-radius:var(--r-xs);border:1px solid var(--border);
  background:transparent;color:var(--fog);cursor:pointer;display:flex;align-items:center;
  justify-content:center;transition:all .2s;text-decoration:none;}
.topbar-back:hover{border-color:var(--ember-border);color:var(--ember);}

/* ── LAYOUT ── */
.layout{max-width:1200px;margin:0 auto;padding:24px 16px 80px;}

/* Desktop : sidebar + main */
.layout-grid{display:grid;grid-template-columns:220px 1fr;gap:20px;align-items:start;}

/* ── SIDEBAR DESKTOP ── */
.filter-sidebar{position:sticky;top:72px;}
.filter-card{background:var(--card);border:1px solid var(--border);border-radius:var(--r);padding:14px;margin-bottom:10px;}
.filter-card-title{font-family:var(--head);font-size:.68rem;font-weight:700;text-transform:uppercase;
  letter-spacing:1.2px;color:var(--fog);margin-bottom:10px;display:flex;align-items:center;gap:5px;}
.filter-card-title i{color:var(--ember);}

/* Difficulté — pills compactes desktop */
.diff-pills{display:flex;flex-direction:column;gap:4px;}
.diff-pill{display:flex;align-items:center;justify-content:space-between;padding:7px 10px;
  border-radius:var(--r-xs);border:1px solid transparent;cursor:pointer;transition:all .15s;
  font-size:.78rem;background:rgba(255,255,255,.02);}
.diff-pill:hover{background:rgba(255,255,255,.04);}
.diff-pill.active{border-color:currentColor;background:rgba(255,255,255,.04);}
.diff-pill.all{color:var(--sand2);}
.diff-pill.all.active{border-color:var(--border2);}
.diff-pill.beginner{color:var(--green);}
.diff-pill.intermediate{color:var(--blue);}
.diff-pill.advanced{color:var(--ember);}
.diff-pill.expert{color:var(--red);}
.diff-pill-left{display:flex;align-items:center;gap:7px;}
.diff-pill-dot{width:6px;height:6px;border-radius:50%;background:currentColor;flex-shrink:0;}
.diff-pill-count{font-size:.65rem;font-family:var(--mono);color:var(--fog);
  background:rgba(255,255,255,.04);padding:1px 5px;border-radius:8px;}

/* Tags sidebar desktop */
.tag-grid{display:flex;flex-wrap:wrap;gap:5px;}
.tag-opt{padding:4px 10px;border-radius:20px;border:1px solid var(--border);
  background:rgba(255,255,255,.02);color:var(--fog);font-size:.72rem;cursor:pointer;transition:all .15s;}
.tag-opt:hover{border-color:var(--ember-border);color:var(--sand2);}
.tag-opt.active{border-color:var(--ember);color:var(--ember);background:var(--ember-dim);}

/* Statut */
.status-opts{display:flex;flex-direction:column;gap:5px;}
.status-opt{display:flex;align-items:center;gap:8px;padding:7px 9px;border-radius:var(--r-xs);
  cursor:pointer;border:1px solid transparent;transition:all .15s;font-size:.78rem;color:var(--sand2);}
.status-opt:hover{background:rgba(255,255,255,.03);}
.status-opt.active{background:var(--ember-dim);border-color:var(--ember-border);color:var(--ember);}
.status-opt input[type=checkbox]{width:13px;height:13px;accent-color:var(--ember);}
.reset-btn{width:100%;padding:7px;border-radius:var(--r-xs);border:1px solid var(--border);
  background:transparent;color:var(--fog);font-family:var(--font);font-size:.75rem;
  cursor:pointer;transition:all .15s;margin-top:4px;}
.reset-btn:hover{border-color:var(--ember-border);color:var(--ember);}

/* ─────────────────────────────────────────────
   FILTER BAR MOBILE — sélecteurs compacts
   ───────────────────────────────────────────── */
.mobile-filter-bar{
  display:none;
  gap:6px;
  padding:10px 12px;
  background:var(--surface);
  border-bottom:1px solid var(--border);
  overflow-x:auto;
  scrollbar-width:none;
  -webkit-overflow-scrolling:touch;
  flex-wrap:nowrap;
  position:sticky;top:56px;z-index:90;
}
.mobile-filter-bar::-webkit-scrollbar{display:none;}

/* Sélecteur compact stylé */
.mf-select{
  appearance:none;-webkit-appearance:none;
  padding:6px 28px 6px 10px;
  border-radius:20px;
  border:1px solid var(--border2);
  background:var(--card);
  color:var(--sand2);
  font-family:var(--mono);font-size:.72rem;
  outline:none;cursor:pointer;
  white-space:nowrap;flex-shrink:0;
  background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6' fill='none'%3E%3Cpath d='M1 1l4 4 4-4' stroke='%237a6a58' stroke-width='1.5' stroke-linecap='round'/%3E%3C/svg%3E");
  background-repeat:no-repeat;
  background-position:right 8px center;
  transition:border-color .15s;
}
.mf-select:focus,.mf-select:hover{border-color:var(--ember-border);color:var(--ember);}
.mf-select option{background:var(--card);}
.mf-select.active{border-color:var(--ember);color:var(--ember);background-color:var(--ember-dim);}

/* Toggle pill mobile */
.mf-toggle{
  padding:6px 12px;border-radius:20px;border:1px solid var(--border2);
  background:var(--card);color:var(--sand2);font-family:var(--mono);font-size:.72rem;
  cursor:pointer;white-space:nowrap;flex-shrink:0;display:flex;align-items:center;gap:5px;
  transition:all .15s;
}
.mf-toggle.active{border-color:var(--ember);color:var(--ember);background:var(--ember-dim);}
.mf-toggle i{font-size:.65rem;}

/* Séparateur mobile */
.mf-sep{width:1px;height:20px;background:var(--border);flex-shrink:0;align-self:center;}

/* ── SEARCH + SORT BAR ── */
.toolbar-bar{display:flex;align-items:center;gap:8px;margin-bottom:14px;flex-wrap:wrap;}
.search-bar{display:flex;align-items:center;gap:8px;background:var(--card);border:1px solid var(--border);
  border-radius:var(--r-sm);padding:0 12px;flex:1;min-width:160px;transition:border-color .2s;}
.search-bar:focus-within{border-color:var(--ember-border);}
.search-bar i{color:var(--fog);font-size:.8rem;flex-shrink:0;}
.search-bar input{background:transparent;border:none;outline:none;color:var(--sand);
  font-family:var(--font);font-size:.84rem;padding:9px 0;width:100%;}
.search-bar input::placeholder{color:var(--fog);}
.sort-sel{padding:9px 10px;background:var(--card);border:1px solid var(--border);
  border-radius:var(--r-sm);color:var(--sand2);font-family:var(--font);font-size:.78rem;
  outline:none;cursor:pointer;}
.sort-sel:hover,.sort-sel:focus{border-color:var(--ember-border);}
.sort-sel option{background:var(--card);}

/* ── CHALLENGE CARDS ── */
.challenges-grid{display:flex;flex-direction:column;gap:8px;}
.c-card{background:var(--card);border:1px solid var(--border);border-radius:var(--r);
  padding:16px;cursor:pointer;transition:all .2s var(--ease);text-decoration:none;display:block;
  position:relative;overflow:hidden;}
.c-card::before{content:'';position:absolute;top:0;left:0;right:0;height:2px;
  background:linear-gradient(90deg,transparent,var(--ember),transparent);opacity:0;transition:opacity .2s;}
.c-card:hover{border-color:var(--ember-border);transform:translateY(-1px);box-shadow:0 8px 32px rgba(0,0,0,.4);}
.c-card:hover::before{opacity:1;}
.c-card.solved{border-color:rgba(62,207,110,.2);}
.c-card.solved::before{background:linear-gradient(90deg,transparent,var(--green),transparent);opacity:.5;}
.c-card.attempted{border-color:rgba(74,158,255,.12);}
.c-card-top{display:flex;align-items:flex-start;gap:12px;}
.c-status-icon{width:36px;height:36px;border-radius:9px;display:flex;align-items:center;
  justify-content:center;font-size:.9rem;flex-shrink:0;margin-top:1px;}
.c-status-icon.solved{background:rgba(62,207,110,.1);color:var(--green);}
.c-status-icon.attempted{background:rgba(74,158,255,.1);color:var(--blue);}
.c-status-icon.open{background:rgba(255,255,255,.04);color:var(--fog);}
.c-info{flex:1;min-width:0;}
.c-top-row{display:flex;align-items:center;gap:6px;flex-wrap:wrap;margin-bottom:4px;}
.diff-badge{display:inline-flex;align-items:center;gap:3px;font-size:.6rem;font-weight:700;
  text-transform:uppercase;letter-spacing:.8px;padding:2px 8px;border-radius:20px;font-family:var(--mono);}
.diff-badge.beginner{background:rgba(62,207,110,.1);color:var(--green);border:1px solid rgba(62,207,110,.2);}
.diff-badge.intermediate{background:rgba(74,158,255,.1);color:var(--blue);border:1px solid rgba(74,158,255,.2);}
.diff-badge.advanced{background:rgba(224,123,53,.1);color:var(--ember);border:1px solid var(--ember-border);}
.diff-badge.expert{background:rgba(224,82,82,.1);color:var(--red);border:1px solid rgba(224,82,82,.2);}
.state-badge{display:inline-flex;align-items:center;gap:3px;font-size:.6rem;font-weight:700;
  padding:2px 8px;border-radius:20px;font-family:var(--mono);}
.state-badge.solved{background:rgba(62,207,110,.1);color:var(--green);}
.state-badge.attempted{background:rgba(74,158,255,.1);color:var(--blue);}
.state-badge.company{background:var(--ember-dim);color:var(--ember);}
.c-title{font-family:var(--head);font-size:.94rem;font-weight:700;color:var(--sand);
  margin-bottom:4px;line-height:1.3;}
.c-desc{font-size:.76rem;color:var(--fog);line-height:1.5;
  overflow:hidden;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;}
.c-footer{display:flex;align-items:center;justify-content:space-between;margin-top:12px;
  padding-top:10px;border-top:1px solid var(--border);flex-wrap:wrap;gap:6px;}
.c-meta{display:flex;align-items:center;gap:10px;flex-wrap:wrap;}
.c-meta-item{display:flex;align-items:center;gap:4px;font-size:.7rem;color:var(--fog);font-family:var(--mono);}
.c-meta-item i{font-size:.62rem;}
.c-tags{display:flex;gap:4px;flex-wrap:wrap;}
.c-tag{font-size:.6rem;padding:2px 7px;border-radius:9px;border:1px solid var(--border);color:var(--fog);font-family:var(--mono);}
.c-xp{font-family:var(--mono);font-size:.76rem;font-weight:700;color:var(--ember);
  background:var(--ember-dim);border:1px solid var(--ember-border);
  border-radius:20px;padding:3px 10px;display:inline-flex;align-items:center;gap:4px;flex-shrink:0;}
.c-score{font-family:var(--mono);font-size:.7rem;color:var(--green);
  display:inline-flex;align-items:center;gap:3px;}

/* ── SKELETON ── */
.skeleton{background:linear-gradient(90deg,var(--card) 25%,var(--card2) 50%,var(--card) 75%);
  background-size:200% 100%;animation:shimmer 1.4s infinite;border-radius:var(--r);}
@keyframes shimmer{0%{background-position:200% 0}100%{background-position:-200% 0}}
.skel-card{height:110px;margin-bottom:8px;}

/* ── EMPTY ── */
.empty-state{text-align:center;padding:50px 20px;}
.empty-icon{font-size:2.8rem;margin-bottom:12px;}
.empty-title{font-family:var(--head);font-size:1rem;font-weight:700;margin-bottom:6px;}
.empty-sub{font-size:.8rem;color:var(--fog);}

/* ── PAGINATION ── */
.pagination{display:flex;align-items:center;justify-content:center;gap:6px;margin-top:24px;flex-wrap:wrap;}
.page-btn{width:34px;height:34px;border-radius:var(--r-xs);border:1px solid var(--border);
  background:transparent;color:var(--sand2);cursor:pointer;font-family:var(--mono);font-size:.78rem;
  transition:all .15s;display:flex;align-items:center;justify-content:center;}
.page-btn:hover,.page-btn.active{border-color:var(--ember);color:var(--ember);background:var(--ember-dim);}
.page-btn:disabled{opacity:.3;cursor:not-allowed;}

/* ── STATS HEADER ── */
.stats-hero{display:grid;grid-template-columns:repeat(4,1fr);gap:8px;margin-bottom:20px;}
.stat-hero-item{background:var(--card);border:1px solid var(--border);border-radius:var(--r);
  padding:12px;text-align:center;}
.stat-hero-val{font-family:var(--mono);font-size:1.3rem;font-weight:700;color:var(--ember);}
.stat-hero-lbl{font-size:.62rem;color:var(--fog);text-transform:uppercase;letter-spacing:1px;margin-top:3px;}

/* ── MOBILE NAV ── */
.mobile-bottom-nav{
  display:none;position:fixed;bottom:0;left:0;right:0;z-index:90;
  background:rgba(12,10,8,.95);backdrop-filter:blur(20px);border-top:1px solid var(--border);
  padding:6px 16px calc(6px + env(safe-area-inset-bottom));
}
@media(min-width:769px){.mobile-bottom-nav{display:none!important;}}
.mobile-bottom-nav nav{display:flex;align-items:center;justify-content:space-around;}
.mnav-btn{display:flex;flex-direction:column;align-items:center;gap:3px;
  color:var(--fog);font-size:.6rem;cursor:pointer;text-decoration:none;padding:4px 8px;
  border-radius:var(--r-xs);transition:color .15s;border:none;background:transparent;font-family:var(--font);}
.mnav-btn i{font-size:1rem;}
.mnav-btn.active{color:var(--ember);}

/* ─────────────────────────────────────────────
   RESPONSIVE
   ───────────────────────────────────────────── */
@media(max-width:900px){
  .layout-grid{grid-template-columns:1fr;}
  .filter-sidebar{display:none;}        /* Remplacé par mobile-filter-bar */
  .mobile-filter-bar{display:flex;}
  .stats-hero{grid-template-columns:repeat(2,1fr);}
  .layout{padding:12px 12px 80px;}
}
@media(max-width:768px){
  .topbar{padding:0 12px;}
  .topbar-title{display:none;}
  .topbar-sep{display:none;}
  .c-card{padding:12px;}
  .c-desc{-webkit-line-clamp:1;}
  .stats-hero{display:none;}
  .mobile-bottom-nav{display:block;}
}
@media(max-width:480px){
  .c-card-top{gap:8px;}
  .c-status-icon{width:30px;height:30px;font-size:.8rem;}
  .toolbar-bar{gap:6px;}
  .sort-sel{font-size:.74rem;padding:8px 8px;}
}