:root {
  --bg:           #f0ede8;
  --bg2:          #e8e4de;
  --card:         rgba(253,250,246,0.88);
  --card-solid:   #fdfaf6;
  --ink:          #1c1814;
  --ink2:         #3a342e;
  --muted:        #8c8077;
  --faint:        #b5afa8;
  --border:       rgba(28,24,20,0.10);
  --border-hard:  rgba(28,24,20,0.18);
  --accent:       #10b981;
  --accent-light: rgba(16,185,129,0.10);
  --accent-glow:  rgba(16,185,129,0.22);
  --success:      #1a7a4a;
  --success-bg:   rgba(26,122,74,0.08);
  --error:        #c0392b;
  --error-bg:     rgba(192,57,43,0.08);
  --neu-out:      4px 4px 10px rgba(0,0,0,0.10), -3px -3px 8px rgba(255,255,255,0.80);
  --neu-in:       inset 2px 2px 5px rgba(0,0,0,0.08), inset -2px -2px 4px rgba(255,255,255,0.72);
  --grid-line:    rgba(28,24,20,0.08);
  --f-display:    'DM Serif Display', Georgia, serif;
  --f-body:       'Syne', system-ui, sans-serif;
  --f-mono:       'DM Mono', 'Fira Mono', monospace;
  --radius:       14px;
}

body.dark {
  --bg:           #141210;
  --bg2:          #1c1916;
  --card:         rgba(28,24,20,0.90);
  --card-solid:   #1e1a16;
  --ink:          #f0ebe4;
  --ink2:         #c8c0b6;
  --muted:        #7a7268;
  --faint:        #524c46;
  --border:       rgba(240,235,228,0.08);
  --border-hard:  rgba(240,235,228,0.16);
  --accent:       #10b981;
  --accent-light: rgba(16,185,129,0.12);
  --accent-glow:  rgba(16,185,129,0.24);
  --success:      #3eb97a;
  --success-bg:   rgba(62,185,122,0.10);
  --error:        #e05c4a;
  --error-bg:     rgba(224,92,74,0.10);
  --neu-out:      4px 4px 10px rgba(0,0,0,0.40), -3px -3px 8px rgba(255,255,255,0.03);
  --neu-in:       inset 2px 2px 5px rgba(0,0,0,0.35), inset -2px -2px 4px rgba(255,255,255,0.03);
  --grid-line:    rgba(240,235,228,0.07);
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  font-family: var(--f-body);
  background: var(--bg);
  color: var(--ink);
  min-height: 100vh;
  display: flex; align-items: center; justify-content: center;
  padding: 24px 16px;
  transition: background .35s, color .35s;
  position: relative;
  overflow-x: hidden;
}

.grain {
  position: fixed; inset: 0; z-index: 0; pointer-events: none; opacity: .03;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  background-size: 180px;
}

.auth-bg {
  position: fixed; inset: 0; z-index: 0; pointer-events: none;
}
.bg-line {
  position: absolute;
  background: var(--grid-line);
}
.bg-line.v { width: 1px; top: 0; bottom: 0; }
.bg-line.h { height: 1px; left: 0; right: 0; }

.auth-wrapper {
  position: relative; z-index: 1;
  width: 100%; max-width: 460px;
  display: flex; flex-direction: column; align-items: center; gap: 20px;
}

.auth-brand {
  display: flex; align-items: center; gap: 10px;
  text-decoration: none;
  animation: fadeUp .5s cubic-bezier(.22,1,.36,1) both;
}
.brand-logo {
  width: 38px; height: 38px; border-radius: 10px;
  background: var(--ink); color: var(--bg);
  font-family: var(--f-display); font-style: italic; font-size: 1.15rem;
  display: flex; align-items: center; justify-content: center;
  box-shadow: var(--neu-out);
}
.brand-name {
  font-family: var(--f-mono);
  font-size: .75rem; font-weight: 500;
  letter-spacing: .16em; text-transform: uppercase;
  color: var(--ink);
}

.auth-card {
  width: 100%;
  background: var(--card);
  backdrop-filter: blur(20px) saturate(1.5);
  -webkit-backdrop-filter: blur(20px) saturate(1.5);
  border: 1px solid var(--border-hard);
  border-radius: 20px;
  padding: 32px 32px 28px;
  box-shadow: 0 24px 64px rgba(0,0,0,.10), var(--neu-out);
  animation: fadeUp .5s .08s cubic-bezier(.22,1,.36,1) both;
}

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(18px); }
  to   { opacity: 1; transform: none; }
}

.tab-switcher {
  display: flex;
  background: var(--bg2);
  border-radius: 10px;
  padding: 3px;
  margin-bottom: 26px;
  box-shadow: var(--neu-in);
}
.tab-btn {
  flex: 1; padding: 9px;
  border: none; background: none; border-radius: 8px;
  font-family: var(--f-mono); font-size: .72rem; font-weight: 500;
  letter-spacing: .06em; text-transform: uppercase;
  color: var(--muted); cursor: pointer; transition: all .2s;
}
.tab-btn.active {
  background: var(--card-solid);
  color: var(--ink);
  box-shadow: var(--neu-out);
}

.form-section { display: none; }
.form-section.active {
  display: block;
  animation: fadeUp .2s cubic-bezier(.22,1,.36,1) both;
}

.form-heading { margin-bottom: 22px; }
.form-heading h2 {
  font-family: var(--f-display); font-style: italic;
  font-size: 1.5rem; color: var(--ink); line-height: 1.1; margin-bottom: 4px;
}
.form-heading p {
  font-family: var(--f-mono); font-size: .68rem;
  color: var(--muted); letter-spacing: .04em;
}

.form-group { margin-bottom: 16px; }
.form-group label {
  display: flex; align-items: center; justify-content: space-between;
  font-family: var(--f-mono); font-size: .68rem; font-weight: 500;
  letter-spacing: .08em; text-transform: uppercase;
  color: var(--muted); margin-bottom: 7px;
}
.forgot-link {
  font-size: .68rem; font-weight: 500; color: var(--accent);
  cursor: pointer; text-transform: none; letter-spacing: 0;
  transition: opacity .2s;
}
.forgot-link:hover { opacity: .7; }

.input-wrap { position: relative; }
.input-icon {
  position: absolute; left: 13px; top: 50%; transform: translateY(-50%);
  color: var(--faint); font-size: .8rem; pointer-events: none;
}
.toggle-pw {
  position: absolute; right: 11px; top: 50%; transform: translateY(-50%);
  background: none; border: none; color: var(--faint);
  font-size: .8rem; cursor: pointer; padding: 4px; border-radius: 4px;
  transition: color .2s;
}
.toggle-pw:hover { color: var(--accent); }

.form-control {
  width: 100%; padding: 11px 40px 11px 38px;
  background: var(--card-solid);
  border: 1px solid var(--border-hard);
  border-radius: 10px;
  font-family: var(--f-mono); font-size: .78rem;
  color: var(--ink);
  box-shadow: var(--neu-in);
  outline: none;
  transition: border-color .2s, box-shadow .2s;
}
.form-control.no-right { padding-right: 14px; }
.form-control::placeholder { color: var(--faint); }
.form-control:focus {
  border-color: var(--accent);
  box-shadow: var(--neu-in), 0 0 0 3px var(--accent-light);
}
.form-control.is-invalid {
  border-color: var(--error);
  box-shadow: var(--neu-in), 0 0 0 3px rgba(192,57,43,0.10);
}
.form-control.is-valid { border-color: var(--success); }

.field-hint {
  font-family: var(--f-mono); font-size: .66rem;
  margin-top: 5px; display: none; letter-spacing: .02em;
}
.field-hint.show { display: block; }
.field-hint.err  { color: var(--error); }
.field-hint.ok   { color: var(--success); }

.otp-wrap { display: flex; gap: 8px; }
.otp-wrap .form-control {
  flex: 1; letter-spacing: 8px; font-size: 1rem; font-weight: 500;
  text-align: center; padding-left: 14px; padding-right: 14px;
}
.btn-get-otp {
  flex-shrink: 0; padding: 0 16px; border-radius: 10px; border: none;
  background: var(--ink); color: var(--bg);
  font-family: var(--f-mono); font-weight: 500; font-size: .7rem;
  letter-spacing: .06em; cursor: pointer;
  box-shadow: var(--neu-out);
  transition: all .2s cubic-bezier(.34,1.56,.64,1);
  white-space: nowrap; display: flex; align-items: center; gap: 6px;
}
.btn-get-otp:hover { background: var(--accent); transform: translateY(-1px); }
.btn-get-otp:disabled { opacity: .5; cursor: not-allowed; transform: none; }
.otp-countdown {
  font-family: var(--f-mono); font-size: .66rem;
  color: var(--muted); margin-top: 5px; display: none;
}
.otp-countdown.show { display: block; }
.otp-countdown span { color: var(--accent); font-weight: 500; }

.pw-strength { margin-top: 8px; display: none; }
.pw-strength.show { display: block; }
.pw-bars { display: flex; gap: 4px; margin-bottom: 4px; }
.pw-bar {
  flex: 1; height: 3px; border-radius: 99px;
  background: var(--border-hard); transition: background .3s;
}
.pw-bar.weak   { background: var(--error); }
.pw-bar.medium { background: #d4a017; }
.pw-bar.strong { background: var(--success); }
.pw-label {
  font-family: var(--f-mono); font-size: .64rem;
  color: var(--muted); letter-spacing: .04em;
}

.btn-submit {
  width: 100%; padding: 12px 20px;
  background: var(--ink); color: var(--bg);
  border: none; border-radius: 10px;
  font-family: var(--f-mono); font-size: .78rem; font-weight: 500;
  letter-spacing: .08em; cursor: pointer;
  box-shadow: var(--neu-out);
  display: flex; align-items: center; justify-content: center; gap: 10px;
  margin-top: 8px;
  transition: all .22s cubic-bezier(.34,1.56,.64,1);
}
.btn-submit:hover {
  background: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px var(--accent-glow);
}
.btn-submit:disabled { opacity: .5; cursor: not-allowed; transform: none; box-shadow: var(--neu-out); }

.alert {
  display: none; gap: 10px; align-items: flex-start;
  padding: 11px 14px; border-radius: 10px;
  font-family: var(--f-mono); font-size: .72rem; line-height: 1.6;
  margin-bottom: 16px; border: 1px solid transparent;
}
.alert.show { display: flex; }
.alert i { flex-shrink: 0; margin-top: 1px; font-size: .8rem; }
.alert-error   { background: var(--error-bg);   color: var(--error);   border-color: rgba(192,57,43,.2); }
.alert-success { background: var(--success-bg); color: var(--success); border-color: rgba(26,122,74,.2); }

.back-btn {
  background: none; border: none; color: var(--accent);
  font-family: var(--f-mono); font-size: .7rem; font-weight: 500;
  letter-spacing: .06em; cursor: pointer; padding: 0;
  display: flex; align-items: center; gap: 6px; margin-bottom: 18px;
  transition: opacity .2s;
}
.back-btn:hover { opacity: .7; }

.back-home {
  font-family: var(--f-mono); font-size: .68rem;
  color: var(--muted); text-decoration: none;
  letter-spacing: .06em;
  display: flex; align-items: center; gap: 7px;
  transition: color .2s;
  animation: fadeUp .5s .16s cubic-bezier(.22,1,.36,1) both;
}
.back-home:hover { color: var(--ink); }

.spinner {
  width: 14px; height: 14px;
  border: 2px solid rgba(255,255,255,.3);
  border-top-color: #fff; border-radius: 50%;
  animation: spin .7s linear infinite; flex-shrink: 0;
}
@keyframes spin { to { transform: rotate(360deg); } }

@media (max-width: 480px) {
  .auth-card { padding: 24px 20px 20px; border-radius: 16px; }
  .form-heading h2 { font-size: 1.3rem; }
}

.remember-wrap {
  margin: 12px 0 4px;
}
.remember-label {
  display: flex; align-items: center; gap: 9px;
  cursor: pointer; user-select: none;
}
.remember-cb { display: none; }
.remember-box {
  width: 17px; height: 17px; border-radius: 5px;
  border: 1.5px solid var(--border-hard);
  background: var(--card-solid);
  box-shadow: var(--neu-in);
  flex-shrink: 0;
  display: flex; align-items: center; justify-content: center;
  transition: all .2s;
  position: relative;
}
.remember-box::after {
  content: '';
  width: 9px; height: 5px;
  border-left: 2px solid #fff;
  border-bottom: 2px solid #fff;
  transform: rotate(-45deg) scale(0);
  transition: transform .15s cubic-bezier(.34,1.56,.64,1);
  position: absolute; top: 3px; left: 2px;
}
.remember-cb:checked + .remember-box {
  background: var(--accent);
  border-color: var(--accent);
  box-shadow: 0 2px 8px var(--accent-glow);
}
.remember-cb:checked + .remember-box::after {
  transform: rotate(-45deg) scale(1);
}
.remember-txt {
  font-family: var(--f-mono);
  font-size: .68rem;
  color: var(--muted);
  letter-spacing: .04em;
}
.remember-label:hover .remember-txt { color: var(--ink); }