/* ==================================================================
   Chemistry Lab — bright & playful kids' theme
   ================================================================== */
:root{
  --pink:#ff5d8f; --yellow:#ffd23f; --green:#3ddc97; --blue:#5b9dff;
  --purple:#c77dff; --orange:#ff8c42; --ink:#2a2350; --paper:#fff;
  --font:'Baloo 2','Comic Sans MS','Trebuchet MS',system-ui,sans-serif;
}
*{box-sizing:border-box;margin:0;padding:0}
html,body{height:100%}
body{
  font-family:var(--font);
  color:var(--ink);
  min-height:100vh;
  background:linear-gradient(135deg,#a1c4fd 0%,#c2e9fb 30%,#fbc2eb 70%,#fda1c4 100%);
  background-attachment:fixed;
  overflow-x:hidden;
}
/* floating bubbles background */
.bubbles{position:fixed;inset:0;z-index:0;overflow:hidden;pointer-events:none}
.bubbles i{
  position:absolute;bottom:-80px;border-radius:50%;
  background:rgba(255,255,255,.35);animation:rise linear infinite;
}
@keyframes rise{to{transform:translateY(-115vh) rotate(360deg);opacity:0}}

a{color:inherit;text-decoration:none}
.wrap{position:relative;z-index:1;max-width:1200px;margin:0 auto;padding:20px}

/* ---------------- Landing ---------------- */
.hero{text-align:center;padding:40px 16px 10px}
.hero h1{
  font-size:clamp(2.2rem,6vw,4rem);font-weight:800;letter-spacing:1px;
  color:#fff;text-shadow:0 4px 0 rgba(0,0,0,.12),0 8px 20px rgba(0,0,0,.2);
  animation:pop-in .6s cubic-bezier(.2,1.4,.4,1) both;
}
.hero p{font-size:1.2rem;color:#fff;margin-top:8px;text-shadow:0 2px 6px rgba(0,0,0,.2)}
.hero .beaker{font-size:3.4rem;display:inline-block;animation:wiggle 2.5s ease-in-out infinite}
@keyframes wiggle{0%,100%{transform:rotate(-8deg)}50%{transform:rotate(8deg)}}
@keyframes pop-in{from{transform:scale(.6);opacity:0}to{transform:scale(1);opacity:1}}

.doors{display:flex;gap:32px;flex-wrap:wrap;justify-content:center;margin-top:36px}
.door{
  width:320px;max-width:90vw;border-radius:32px;padding:36px 28px;text-align:center;
  color:#fff;cursor:pointer;position:relative;overflow:hidden;
  box-shadow:0 14px 30px rgba(0,0,0,.22);
  transition:transform .25s cubic-bezier(.2,1.4,.4,1),box-shadow .25s;
  animation:float-in .7s both;
}
.door:nth-child(2){animation-delay:.15s}
@keyframes float-in{from{transform:translateY(40px);opacity:0}to{transform:translateY(0);opacity:1}}
.door:hover{transform:translateY(-10px) scale(1.03) rotate(-1deg);box-shadow:0 22px 44px rgba(0,0,0,.3)}
.door.sophie{background:linear-gradient(160deg,#ff9ac1,#ff5d8f 60%,#c77dff)}
.door.toby{background:linear-gradient(160deg,#7ee8fa,#5b9dff 60%,#3ddc97)}
.door .avatar{font-size:5rem;display:block;animation:bob 3s ease-in-out infinite}
.door:nth-child(2) .avatar{animation-delay:.4s}
@keyframes bob{0%,100%{transform:translateY(0)}50%{transform:translateY(-12px)}}
.door h2{font-size:2rem;margin:10px 0 4px}
.door .age{opacity:.9;font-weight:600}
.door .go{margin-top:18px;display:inline-block;background:rgba(255,255,255,.25);
  padding:10px 22px;border-radius:999px;font-weight:700;backdrop-filter:blur(4px)}
.door .sparkle{position:absolute;font-size:1.4rem;opacity:.85;animation:twinkle 2s infinite}
.door .s1{top:16px;left:20px} .door .s2{top:30px;right:24px;animation-delay:.6s}
.door .s3{bottom:20px;left:30px;animation-delay:1s}
@keyframes twinkle{0%,100%{transform:scale(1);opacity:.4}50%{transform:scale(1.5);opacity:1}}

/* ---------------- Top bar (inner pages) ---------------- */
.topbar{display:flex;align-items:center;gap:14px;flex-wrap:wrap;margin-bottom:14px}
.back{background:#fff;color:var(--ink);padding:10px 18px;border-radius:999px;font-weight:700;
  box-shadow:0 6px 14px rgba(0,0,0,.14);transition:transform .2s}
.back:hover{transform:translateX(-4px) scale(1.05)}
.page-title{font-size:1.9rem;color:#fff;text-shadow:0 3px 0 rgba(0,0,0,.12);font-weight:800}
.page-title .who{font-size:2.4rem;vertical-align:-4px;margin-right:6px}

/* ---------------- Tabs ---------------- */
.tabs{display:flex;gap:10px;flex-wrap:wrap;margin:6px 0 18px}
.tab{
  border:none;cursor:pointer;font-family:var(--font);font-weight:800;font-size:1.05rem;
  padding:12px 22px;border-radius:999px;color:var(--ink);background:rgba(255,255,255,.7);
  box-shadow:0 6px 14px rgba(0,0,0,.12);transition:transform .18s,background .2s;
}
.tab:hover{transform:translateY(-3px) scale(1.04)}
.tab.active{background:#fff;color:var(--pink);box-shadow:0 8px 20px rgba(255,93,143,.4);
  transform:translateY(-2px) scale(1.06)}
.tab .ico{margin-right:6px}

.panel{display:none;animation:fade-up .4s both}
.panel.active{display:block}
@keyframes fade-up{from{opacity:0;transform:translateY(14px)}to{opacity:1;transform:none}}

.card{background:rgba(255,255,255,.82);border-radius:26px;padding:20px;
  box-shadow:0 12px 30px rgba(0,0,0,.14);backdrop-filter:blur(4px)}
.card h2{color:var(--ink);margin-bottom:4px;font-size:1.5rem}
.card .lead{color:#5b5480;margin-bottom:14px}

/* ---------------- Periodic table ---------------- */
.ptable-scroll{overflow-x:auto;padding:6px 2px 12px}
.ptable{
  display:grid;grid-template-columns:repeat(18,minmax(46px,1fr));
  grid-auto-rows:minmax(46px,auto);gap:5px;min-width:900px;
}
.el{
  position:relative;border:none;cursor:pointer;border-radius:10px;
  color:#fff;font-family:var(--font);padding:3px 2px;aspect-ratio:1/1;
  display:flex;flex-direction:column;align-items:center;justify-content:center;
  box-shadow:0 3px 0 rgba(0,0,0,.18);transition:transform .12s ease, box-shadow .12s;
  overflow:hidden;line-height:1;
}
.el:hover{transform:translateY(-4px) scale(1.12);z-index:5;box-shadow:0 10px 18px rgba(0,0,0,.3)}
.el:active{transform:scale(.96)}
.el-num{position:absolute;top:3px;left:5px;font-size:.52rem;opacity:.85;font-weight:600}
.el-sym{font-size:1.1rem;font-weight:800;margin-top:2px}
.el-name{font-size:.44rem;opacity:.9;text-align:center;padding:0 1px;
  white-space:nowrap;overflow:hidden;text-overflow:ellipsis;max-width:100%}
.el .tick{position:absolute;inset:0;display:none;align-items:center;justify-content:center;
  font-size:1.8rem;background:rgba(61,220,151,.85);color:#fff;font-weight:900}
.el.secured .tick{display:flex;animation:pop-in .3s both}
.el.secured{filter:saturate(.6)}
.el.is-common{outline:2px solid #fff;outline-offset:-2px;
  box-shadow:0 0 0 2px rgba(255,255,255,.5),0 3px 0 rgba(0,0,0,.18),0 0 14px rgba(255,255,255,.6)}
.el.dimmed{opacity:.4}
.el.placeholder,.el.placeholder:hover{background:transparent;box-shadow:none;color:#4a3f7a;
  transform:none;cursor:default;font-size:.6rem;font-weight:700;border:2px dashed rgba(74,63,122,.4)}
.el.shake{animation:shake .4s}
.el.pop-anim{animation:pop-in .4s}
@keyframes shake{0%,100%{transform:translateX(0)}25%{transform:translateX(-5px)}75%{transform:translateX(5px)}}

/* category colours */
.cat-alkali{background:linear-gradient(160deg,#ff9a6b,#ff6b6b)}
.cat-alkaline{background:linear-gradient(160deg,#ffd36b,#ffab2e)}
.cat-transition{background:linear-gradient(160deg,#6bd6ff,#3d9dff)}
.cat-post{background:linear-gradient(160deg,#9be15d,#3ddc97)}
.cat-metalloid{background:linear-gradient(160deg,#c77dff,#9d4edd)}
.cat-nonmetal{background:linear-gradient(160deg,#5be7c4,#2bb59a)}
.cat-halogen{background:linear-gradient(160deg,#ffe37a,#ffc93c);color:#5a4a00}
.cat-halogen .el-num{color:#5a4a00}
.cat-noble{background:linear-gradient(160deg,#ff8fd0,#ff5d8f)}
.cat-lanthanide{background:linear-gradient(160deg,#a0e9ff,#6ac6ff)}
.cat-actinide{background:linear-gradient(160deg,#f6a5c0,#e46b9c)}

/* legend */
.legend{display:flex;gap:8px 14px;flex-wrap:wrap;margin-top:14px;font-size:.82rem;color:var(--ink)}
.legend span{display:inline-flex;align-items:center;gap:6px;font-weight:600}
.legend i{width:16px;height:16px;border-radius:5px;display:inline-block}
.hint{margin-top:10px;color:#5b5480;font-weight:600}

/* ---------------- Modal ---------------- */
#modal{position:fixed;inset:0;z-index:50;background:rgba(30,20,60,.55);
  display:none;align-items:center;justify-content:center;padding:16px;backdrop-filter:blur(3px)}
#modal.open{display:flex;animation:fade-up .2s both}
.modal-box{background:#fff;border-radius:28px;max-width:460px;width:100%;
  max-height:90vh;overflow:auto;padding:26px;position:relative;
  box-shadow:0 24px 60px rgba(0,0,0,.4);animation:pop-in .35s cubic-bezier(.2,1.4,.4,1) both}
.modal-close{position:absolute;top:14px;right:16px;font-size:1.6rem;cursor:pointer;
  border:none;background:#f0eef8;width:40px;height:40px;border-radius:50%;font-weight:800;color:var(--ink)}
.modal-close:hover{background:#ffd7e5}
.modal-tile{width:96px;height:96px;border-radius:18px;color:#fff;margin:0 auto 6px;
  display:flex;flex-direction:column;align-items:center;justify-content:center;position:relative;
  box-shadow:0 8px 18px rgba(0,0,0,.25)}
.modal-tile .mt-num{position:absolute;top:6px;left:10px;font-size:.7rem;opacity:.85}
.modal-tile .mt-sym{font-size:2.4rem;font-weight:800}
.modal-tile .mt-mass{font-size:.7rem;opacity:.85}
.modal-name{text-align:center;font-size:1.8rem;margin-top:4px}
.modal-cat{text-align:center;color:#8b83b0;font-weight:700;margin-bottom:8px}
.modal-tag{text-align:center;font-size:1.05rem;color:var(--pink);font-weight:700;margin-bottom:14px}
.info-block{background:#f6f4ff;border-radius:16px;padding:12px 16px;margin-bottom:10px}
.info-block h3{font-size:1rem;margin-bottom:4px;color:var(--ink)}
.info-block ul{margin-left:18px} .info-block li{margin:2px 0}
.info-block.fun{background:linear-gradient(160deg,#fff3c4,#ffe08a)}
.secure-btn{width:100%;margin-top:8px;border:none;cursor:pointer;font-family:var(--font);
  font-weight:800;font-size:1.05rem;padding:14px;border-radius:16px;color:#fff;
  background:linear-gradient(160deg,#3ddc97,#2bb59a);box-shadow:0 6px 0 #1f8a76;transition:transform .12s}
.secure-btn:hover{transform:translateY(-2px)} .secure-btn:active{transform:translateY(2px);box-shadow:0 2px 0 #1f8a76}
.secure-btn.is-on{background:linear-gradient(160deg,#ffd23f,#ffab2e);box-shadow:0 6px 0 #c8850f;color:#5a4a00}

/* ---------------- Progress bar ---------------- */
.prog-head{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:10px;margin-bottom:8px}
.prog-count{font-weight:800;font-size:1.2rem;color:var(--pink)}
.prog-track{height:22px;background:#efeaff;border-radius:999px;overflow:hidden;margin-bottom:6px;
  box-shadow:inset 0 2px 4px rgba(0,0,0,.1)}
.prog-fill{height:100%;width:0;border-radius:999px;
  background:linear-gradient(90deg,#3ddc97,#ffd23f,#ff5d8f);transition:width .5s cubic-bezier(.2,1.4,.4,1)}
.prog-msg{font-weight:700;color:var(--ink);margin-bottom:12px}

/* ---------------- Quiz ---------------- */
.quiz-top{display:flex;justify-content:space-between;align-items:center;margin-bottom:6px;font-weight:800}
#q-count{color:#7a72a8} #q-score{color:var(--pink);font-size:1.2rem}
.q-bar{height:14px;background:#efeaff;border-radius:999px;overflow:hidden;margin-bottom:18px}
.q-bar-fill{height:100%;width:0;background:linear-gradient(90deg,#5b9dff,#c77dff);transition:width .4s}
.q-prompt{font-size:1.5rem;text-align:center;margin:8px 0 20px;font-weight:800;line-height:1.3}
.q-prompt b{color:var(--blue)}
.q-options{display:grid;grid-template-columns:1fr 1fr;gap:14px}
@media(max-width:520px){.q-options{grid-template-columns:1fr}}
.q-opt{border:none;cursor:pointer;font-family:var(--font);font-weight:800;font-size:1.25rem;
  padding:22px 12px;border-radius:18px;color:#fff;box-shadow:0 5px 0 rgba(0,0,0,.18);
  transition:transform .12s;position:relative}
.q-opt:hover{transform:translateY(-3px) scale(1.03)}
.q-opt:active{transform:translateY(2px)}
.q-opt.locked{cursor:default}
.q-opt.right{background:linear-gradient(160deg,#3ddc97,#2bb59a)!important;
  box-shadow:0 0 0 4px #fff,0 8px 20px rgba(61,220,151,.6);animation:pop-in .3s}
.q-opt.right::after{content:"✓";position:absolute;top:6px;right:12px;font-size:1.4rem}
.q-opt.wrong{background:linear-gradient(160deg,#ff8a8a,#ff5d5d)!important;opacity:.9}
.q-opt.wrong::after{content:"✗";position:absolute;top:6px;right:12px;font-size:1.4rem}
.q-feedback{text-align:center;font-size:1.3rem;font-weight:800;margin:18px 0 6px;
  min-height:1.6em;opacity:0;transition:opacity .2s}
.q-feedback.show{opacity:1}
.q-feedback b{color:var(--pink)}
.center{text-align:center;margin-top:6px}
.big-btn{border:none;cursor:pointer;font-family:var(--font);font-weight:800;font-size:1.1rem;
  padding:14px 30px;border-radius:16px;color:#fff;margin:6px;
  background:linear-gradient(160deg,#ff8fbf,#ff5d8f);box-shadow:0 6px 0 #c23768;transition:transform .12s}
.big-btn:hover{transform:translateY(-2px)} .big-btn:active{transform:translateY(2px);box-shadow:0 2px 0 #c23768}
.big-btn.ghost{background:linear-gradient(160deg,#7ea8ff,#5b9dff);box-shadow:0 6px 0 #3a6fc8}
#next-btn{display:none}

.quiz-result{display:none;text-align:center;padding:20px}
.quiz-result.show{display:block;animation:pop-in .4s}
.result-emoji{font-size:5rem;animation:bob 1.5s ease-in-out infinite}
.quiz-result h2{font-size:2rem;color:var(--pink);margin:6px 0}
.result-score{font-size:1.4rem;margin:6px 0}
.result-sub{color:#5b5480;font-weight:600;margin-bottom:6px}
.result-best{color:#8b83b0;font-weight:700;margin-bottom:12px}

/* ---------------- Quiz: element chooser ---------------- */
.el .sel-badge{position:absolute;top:2px;right:2px;width:18px;height:18px;border-radius:50%;
  background:#fff;color:#2bb59a;font-size:.8rem;font-weight:900;display:none;
  align-items:center;justify-content:center;box-shadow:0 1px 3px rgba(0,0,0,.35)}
.el.selected .sel-badge{display:flex;animation:pop-in .3s}
.el.selected{outline:3px solid #2bb59a !important;outline-offset:-3px;
  box-shadow:0 0 0 3px rgba(43,181,154,.55),0 6px 14px rgba(43,181,154,.5) !important;
  transform:translateY(-2px)}
.chip-row{display:flex;gap:8px;flex-wrap:wrap}
.chip{border:none;cursor:pointer;font-family:var(--font);font-weight:700;font-size:.9rem;
  padding:8px 14px;border-radius:999px;color:#fff;background:linear-gradient(160deg,#5be7c4,#2bb59a);
  box-shadow:0 4px 0 rgba(0,0,0,.15);transition:transform .12s}
.chip:hover{transform:translateY(-2px)} .chip:active{transform:translateY(1px)}
.chip.ghost{background:linear-gradient(160deg,#ffb3c6,#ff5d8f)}

/* ---------------- Quiz: fill in the blank ---------------- */
.q-sub{font-size:1rem;color:#7a72a8;font-weight:700}
.q-fill{display:flex;gap:12px;justify-content:center;flex-wrap:wrap;margin-bottom:4px}
#q-input{font-family:var(--font);font-weight:800;font-size:1.6rem;text-align:center;
  padding:14px 18px;border-radius:16px;border:3px solid #d9d2ff;width:min(320px,80vw);
  color:var(--ink);background:#fff;outline:none;transition:border-color .15s,box-shadow .15s}
#q-input:focus{border-color:var(--blue);box-shadow:0 0 0 4px rgba(91,157,255,.25)}
#q-input.right{border-color:#2bb59a;box-shadow:0 0 0 4px rgba(61,220,151,.35);color:#2bb59a}
#q-input.wrong{border-color:#ff5d5d;box-shadow:0 0 0 4px rgba(255,93,93,.3);color:#ff5d5d}
#q-input:disabled{opacity:1}

/* ---------------- Confetti ---------------- */
.confetti-layer{position:fixed;inset:0;z-index:100;pointer-events:none;overflow:hidden}
.confetti-layer i{position:absolute;top:-20px;border-radius:3px;animation:fall linear forwards}
@keyframes fall{to{transform:translateY(108vh) rotate(720deg);opacity:.9}}

/* ---------------- Coming soon (Toby) ---------------- */
.coming{background:rgba(255,255,255,.85);border-radius:28px;padding:50px 30px;text-align:center;
  max-width:560px;margin:30px auto;box-shadow:0 14px 34px rgba(0,0,0,.16)}
.coming .big{font-size:5rem;animation:bob 3s ease-in-out infinite;display:inline-block}
.coming h2{font-size:2rem;margin:10px 0}
.coming p{color:#5b5480;font-weight:600;font-size:1.1rem;margin-bottom:8px}