:root {
  --brand: #6c4cf1;
  --brand-dark: #5636d6;
  --bg: #f5f4fb;
  --text: #1f1b2e;
  --muted: #6b6779;
  --error: #d64545;
  --error-bg: #fdeaea;
  --success: #1e7e46;
  --success-bg: #e7f7ee;
  --card-bg: #ffffff;
  --radius: 16px;
}

* {
  box-sizing: border-box;
}

html, body {
  height: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  padding: 20px;
}

.card {
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: 0 10px 30px rgba(30, 20, 60, 0.08);
  padding: 40px 32px;
  width: 100%;
  max-width: 380px;
  text-align: center;
}

.logo {
  margin-bottom: 18px;
}

.logo img {
  width: 72px;
  height: 72px;
  display: block;
  margin: 0 auto;
}

.brand-name {
  font-weight: 700;
  font-size: 1.25rem;
  margin: 0 0 4px;
}

.subtitle {
  color: var(--muted);
  font-size: 0.95rem;
  margin: 0 0 28px;
  line-height: 1.4;
}

.field {
  text-align: left;
  margin-bottom: 18px;
}

label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 6px;
}

input[type="text"] {
  width: 100%;
  padding: 13px 14px;
  font-size: 1rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  border: 1.5px solid #dcd9ea;
  border-radius: 10px;
  outline: none;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
  -webkit-appearance: none;
}

input[type="text"]::placeholder {
  text-transform: none;
  letter-spacing: normal;
  color: #a9a5bb;
}

input[type="text"]:focus {
  border-color: var(--brand);
  box-shadow: 0 0 0 3px rgba(108, 76, 241, 0.15);
}

input[type="text"].shake {
  animation: shake 0.35s ease;
  border-color: var(--error);
}

@keyframes shake {
  10%, 90% { transform: translateX(-1px); }
  20%, 80% { transform: translateX(2px); }
  30%, 50%, 70% { transform: translateX(-4px); }
  40%, 60% { transform: translateX(4px); }
}

button.submit {
  width: 100%;
  padding: 13px 14px;
  font-size: 1rem;
  font-weight: 600;
  color: #fff;
  background: var(--brand);
  border: none;
  border-radius: 10px;
  cursor: pointer;
  transition: background 0.15s ease, opacity 0.15s ease;
}

button.submit:hover {
  background: var(--brand-dark);
}

button.submit:disabled {
  opacity: 0.7;
  cursor: default;
}

.alert {
  display: flex;
  align-items: center;
  gap: 8px;
  border-radius: 10px;
  padding: 10px 14px;
  font-size: 0.88rem;
  margin-bottom: 18px;
  text-align: left;
}

.alert-error {
  background: var(--error-bg);
  color: var(--error);
}

.alert-success {
  background: var(--success-bg);
  color: var(--success);
}

.alert[hidden] {
  display: none;
}

.footer-note {
  margin-top: 22px;
  font-size: 0.78rem;
  color: var(--muted);
}

/* Welcome / success page */
.welcome-card { max-width: 460px; text-align: left; }
.welcome-card h1 { margin: 0 0 12px; font-size: 1.4rem; }
.welcome-card p { color: var(--muted); line-height: 1.5; }
.back-link {
  display: inline-block;
  margin-top: 22px;
  color: var(--brand);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.9rem;
}
.back-link:hover { text-decoration: underline; }

/* --- Responsive breakpoints --- */

/* Small phones */
@media (max-width: 360px) {
  .card {
    padding: 30px 20px;
  }
  .logo img {
    width: 56px;
    height: 56px;
  }
  .brand-name {
    font-size: 1.1rem;
  }
}

/* Tablets and up: a touch more breathing room */
@media (min-width: 600px) {
  .card {
    padding: 48px 44px;
  }
}

/* Large desktop: cap width, slightly bigger type */
@media (min-width: 1200px) {
  .card {
    max-width: 420px;
  }
  .brand-name {
    font-size: 1.4rem;
  }
}

/* Short viewports (landscape phones): avoid clipping */
@media (max-height: 480px) {
  body {
    align-items: flex-start;
    padding-top: 24px;
  }
}