:root{
  --ink:#04101c; --navy:#071b2e; --deep:#0b2a44; --line:rgba(255,255,255,.12);
  --cyan:#22d3ee; --cyan-d:#0891b2; --gold:#f5c451; --text:#dbe7f3; --muted:#8ea6bd;
  --paper:#f4f8fb; --card:#ffffff; --dark-text:#0b2a44;
  --err:#ef4444; --ok:#34d399;
}
*{box-sizing:border-box;margin:0;padding:0}
body{font-family:Inter,system-ui,sans-serif;background:var(--paper);color:var(--dark-text);line-height:1.55;-webkit-font-smoothing:antialiased}
h1,h2,h3{font-family:Sora,sans-serif;letter-spacing:-.02em}
a{color:inherit;text-decoration:none}
button{font-family:inherit;cursor:pointer}
:focus-visible{outline:3px solid var(--cyan);outline-offset:2px}

.auth-body{min-height:100vh;display:flex;align-items:center;justify-content:center;padding:2.5vh 2vw;background:var(--paper)}
.auth-shell{width:min(980px,100%);min-height:min(88vh,720px);display:grid;grid-template-columns:1fr 1.15fr;border-radius:28px;overflow:hidden;box-shadow:0 30px 80px rgba(11,42,68,.18);background:var(--card)}

/* left brand panel */
.side{position:relative;overflow:hidden;color:#fff;padding:2.6rem 2.2rem;display:flex;flex-direction:column;justify-content:space-between;
  background:radial-gradient(ellipse at 30% 15%,#0f4a72,var(--navy) 55%,var(--ink))}
.side::before{content:"";position:absolute;inset:0;background-image:linear-gradient(var(--line) 1px,transparent 1px),linear-gradient(90deg,var(--line) 1px,transparent 1px);background-size:40px 40px;opacity:.2;mask-image:radial-gradient(circle at 30% 60%,#000,transparent 72%);-webkit-mask-image:radial-gradient(circle at 30% 60%,#000,transparent 72%)}
.rings{position:absolute;z-index:0;left:15%;bottom:10%;width:0;height:0}
.rings i{position:absolute;border:1.5px solid var(--cyan);border-radius:50%;transform:translate(-50%,-50%);opacity:0;animation:ping 7s ease-out infinite}
.rings i:nth-child(2){animation-delay:2.3s}.rings i:nth-child(3){animation-delay:4.6s}
@keyframes ping{0%{width:60px;height:60px;opacity:.55}100%{width:640px;height:640px;opacity:0}}
.side-content{position:relative;z-index:1}
.back{display:inline-flex;align-items:center;gap:.5rem;font-size:.85rem;color:var(--text);opacity:.85;margin-bottom:2.2rem;transition:opacity .2s,transform .2s}
.back:hover{opacity:1;transform:translateX(-3px)}
.brand{display:flex;align-items:center;gap:.6rem;font-family:Sora;font-weight:800;font-size:1.15rem;margin-bottom:1.6rem}
.brand .mk{width:34px;height:34px;border-radius:10px;display:grid;place-items:center;background:linear-gradient(135deg,var(--cyan),#3b82f6);color:var(--ink);font-size:.95rem}
.brand em{font-style:normal;color:var(--cyan)}
.side h2{font-size:1.55rem;font-weight:800;line-height:1.25;margin-bottom:.8rem}
.side>.side-content>p{color:var(--text);opacity:.85;font-size:.92rem;max-width:340px;margin-bottom:1.6rem}
.side-points{list-style:none;display:flex;flex-direction:column;gap:.7rem}
.side-points li{font-size:.85rem;color:var(--text);display:flex;align-items:flex-start;gap:.55rem}
.side-points i{color:var(--cyan);margin-top:.15rem;flex-shrink:0}
.side .meta{position:relative;z-index:1;font-size:.78rem;color:var(--muted)}

/* right form panel */
.panel{padding:2.6rem 2.8rem;display:flex;flex-direction:column;position:relative;overflow:hidden}

.tabs{position:relative;display:flex;gap:.2rem;background:#eef3f8;border-radius:999px;padding:5px;margin-bottom:1.8rem}
.tab{position:relative;z-index:2;flex:1;border:0;background:none;padding:.65rem 0;border-radius:999px;font-weight:600;font-size:.85rem;color:#5a7488;transition:color .3s}
.tab.on{color:var(--ink)}
.tab-ind{position:absolute;z-index:1;top:5px;left:5px;height:calc(100% - 10px);width:calc(33.333% - 3.33px);background:var(--cyan);border-radius:999px;transition:transform .35s cubic-bezier(.4,0,.2,1)}

.form{display:none;flex-direction:column;gap:1.1rem;animation:fadeUp .4s ease both}
.form.on{display:flex}
@keyframes fadeUp{from{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}
.form h3{font-size:1.4rem;font-weight:800;margin-bottom:.15rem}
.form .sub{color:#5a7488;font-size:.9rem;margin-bottom:.2rem}

label{display:flex;flex-direction:column;gap:.4rem;font-size:.85rem;font-weight:600;color:var(--dark-text)}
label .req{font-weight:500;color:#8393a3;font-size:.75rem}
input,select{font-family:inherit;font-size:.95rem;font-weight:500;padding:.8rem .95rem;border-radius:10px;border:1.5px solid #dde6ee;background:#fbfcfe;color:var(--dark-text);transition:border-color .2s,box-shadow .2s}
input::placeholder{color:#a7b4c0;font-weight:400}
input:focus,select:focus{border-color:var(--cyan);box-shadow:0 0 0 4px rgba(34,211,238,.15);outline:none}
input.bad{border-color:var(--err);animation:shake .35s}
.bad-shake{animation:shake .35s}
@keyframes shake{0%,100%{transform:translateX(0)}20%{transform:translateX(-6px)}40%{transform:translateX(6px)}60%{transform:translateX(-4px)}80%{transform:translateX(4px)}}
.err{min-height:1em;font-size:.78rem;font-weight:600;color:var(--err)}

.pw-wrap{position:relative;display:flex}
.pw-wrap input{flex:1;padding-right:2.6rem}
.eye{position:absolute;right:.7rem;top:50%;transform:translateY(-50%);background:none;border:0;color:#8393a3;font-size:.95rem}
.eye:hover{color:var(--cyan-d)}

.two{display:grid;grid-template-columns:1fr 1fr;gap:1rem}
@media(max-width:560px){.two{grid-template-columns:1fr}}

.meter{height:5px;border-radius:99px;background:#eef3f8;overflow:hidden;margin-top:-.4rem}
.meter .bar{height:100%;width:0%;border-radius:99px;background:var(--err);transition:width .35s ease,background .35s ease}
.hint{font-size:.76rem;color:#8393a3;margin-top:-.55rem}

.chk{flex-direction:row;align-items:center;gap:.55rem;font-weight:500;font-size:.85rem;color:#4a6378}
.chk input{width:16px;height:16px;accent-color:var(--cyan-d);padding:0}

.row{display:flex;align-items:center;justify-content:space-between;font-size:.85rem;margin-top:-.3rem}
.link{color:var(--cyan-d);font-weight:600}
.link:hover{text-decoration:underline}

.btn{display:inline-flex;align-items:center;justify-content:center;gap:.55rem;font-weight:700;font-size:.95rem;padding:.85rem 1.4rem;border-radius:10px;border:1px solid transparent;transition:transform .2s,box-shadow .2s}
.btn:hover{transform:translateY(-2px)}
.btn:active{transform:translateY(0)}
.btn-cyan{background:linear-gradient(135deg,var(--cyan),#3b82f6);color:#fff}
.btn-cyan:hover{box-shadow:0 10px 26px rgba(34,211,238,.35)}
.wide{width:100%;margin-top:.2rem}

.switch{text-align:center;font-size:.85rem;color:#5a7488;margin-top:.2rem}
.switch a{color:var(--cyan-d);font-weight:700}
.switch a:hover{text-decoration:underline}

/* toast */
.toast{position:fixed;left:50%;bottom:28px;transform:translate(-50%,120%);background:var(--ink);color:#fff;padding:.85rem 1.4rem;border-radius:12px;font-size:.9rem;font-weight:600;display:flex;align-items:center;gap:.6rem;box-shadow:0 14px 34px rgba(0,0,0,.3);transition:transform .35s cubic-bezier(.4,0,.2,1);z-index:50}
.toast.show{transform:translate(-50%,0)}
.toast i{color:var(--ok)}
.toast.bad i{color:var(--err)}

@media(max-width:820px){
  .auth-shell{grid-template-columns:1fr;min-height:0}
  .side{padding:2rem 1.6rem;min-height:220px}
  .side h2{font-size:1.25rem}
  .side>.side-content>p,.side-points{display:none}
  .panel{padding:2rem 1.5rem 2.4rem}
}
@media(prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}}