:root {
  --bg: #04131d;
  --bg-soft: #0d2433;
  --panel: rgba(8, 24, 36, 0.82);
  --panel-border: rgba(11, 197, 234, 0.24);
  --text: #f1f6fa;
  --muted: #adc6d8;
  --primary: #0bc5ea;
  --primary-hover: #09a3c1;
  --secondary: #2f4858;
  --secondary-hover: #3f5f74;
  --danger: #f87171;
  --success: #34d399;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  background-color: var(--bg);
  color: var(--text);
}

a {
  color: var(--primary);
}

.page {
  min-height: 100vh;
  background-position: center;
  background-repeat: no-repeat;
  background-size: cover;
}

.page-landing {
  background-image: linear-gradient(rgba(4, 19, 29, 0.65), rgba(4, 19, 29, 0.72)),
    url("/public/assets/Landing_Page_Enter_Selection.png");
}

.page-classroom {
  background-image: linear-gradient(rgba(4, 19, 29, 0.68), rgba(4, 19, 29, 0.84)),
    url("/public/assets/Classroom.png");
}

.page-auth,
.page-characters {
  background: radial-gradient(circle at 20% 10%, #134159 0%, var(--bg) 42%);
}

.site-nav {
  width: 100%;
  padding: 0.85rem 1.25rem;
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  background: rgba(3, 11, 17, 0.92);
  border-bottom: 1px solid var(--panel-border);
  backdrop-filter: blur(8px);
}

.brand {
  color: var(--text);
  font-weight: 700;
  letter-spacing: 0.04em;
  text-decoration: none;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  flex-wrap: wrap;
}

.nav-links a {
  color: var(--muted);
  text-decoration: none;
  font-weight: 600;
}

.nav-links a:hover {
  color: var(--primary);
}

.nav-auth {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.auth-chip {
  padding: 0.2rem 0.55rem;
  border-radius: 999px;
  border: 1px solid var(--panel-border);
  color: var(--muted);
  font-size: 0.8rem;
}

.nav-action {
  color: var(--text);
  font-weight: 600;
  text-decoration: none;
}

.page-content {
  width: min(1120px, calc(100% - 2rem));
  margin: 0 auto;
  padding: 2.25rem 0 2.75rem;
}

.hero-panel,
.panel,
.auth-panel,
.cta-card {
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: 14px;
  box-shadow: 0 14px 30px rgba(0, 0, 0, 0.22);
}

.hero-panel {
  padding: 2.25rem;
  text-align: center;
}

.landing-panel {
  max-width: 760px;
  margin: 3.5rem auto 0;
}

.title {
  margin: 0 0 0.7rem;
  font-size: clamp(2.2rem, 5vw, 3.35rem);
}

.subtitle {
  margin: 0 0 1.8rem;
  color: var(--muted);
  font-size: clamp(1rem, 2.6vw, 1.4rem);
}

.options {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0.8rem;
}

.btn-primary,
.btn-secondary {
  border: none;
  border-radius: 8px;
  padding: 0.75rem 1.1rem;
  font-size: 0.98rem;
  font-weight: 700;
  cursor: pointer;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: background-color 0.2s ease, transform 0.2s ease;
}

.btn-primary {
  background: var(--primary);
  color: #021018;
}

.btn-primary:hover {
  background: var(--primary-hover);
}

.btn-secondary {
  background: var(--secondary);
  color: var(--text);
}

.btn-secondary:hover {
  background: var(--secondary-hover);
}

.btn-primary:disabled,
.btn-secondary:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.btn-sm {
  padding: 0.45rem 0.65rem;
  font-size: 0.82rem;
}

.btn-full {
  width: 100%;
}

.is-hidden {
  display: none;
}

.auth-panel {
  width: min(500px, 100%);
  margin: 2rem auto 0;
  padding: 2rem;
}

.auth-panel h1 {
  margin-top: 0;
  margin-bottom: 0.5rem;
}

.auth-panel p {
  margin-top: 0;
  color: var(--muted);
}

.auth-form {
  text-align: left;
}

.auth-form label {
  display: block;
  margin: 0.72rem 0 0.35rem;
  font-weight: 600;
}

.auth-form input {
  width: 100%;
  border: 1px solid rgba(173, 198, 216, 0.3);
  border-radius: 8px;
  background: rgba(2, 10, 16, 0.65);
  color: var(--text);
  padding: 0.68rem 0.72rem;
}

.auth-form input:focus {
  border-color: var(--primary);
  outline: none;
}

.divider {
  margin: 0.9rem 0 1rem;
  text-align: center;
  color: var(--muted);
  position: relative;
}

.divider::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 50%;
  border-top: 1px solid rgba(173, 198, 216, 0.25);
}

.divider span {
  background: rgba(8, 24, 36, 0.95);
  position: relative;
  padding: 0 0.55rem;
}

.auth-footer {
  margin-top: 1rem;
}

.status-text {
  min-height: 1.4rem;
  margin: 0.8rem 0 0;
  color: var(--muted);
}

.status-error {
  color: var(--danger);
}

.status-success {
  color: var(--success);
}

.character-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 0.95rem;
  width: 100%;
  margin: 1.2rem auto 1.1rem;
}

.character-card {
  background: rgba(3, 13, 20, 0.76);
  border: 1px solid rgba(173, 198, 216, 0.16);
  border-radius: 10px;
  padding: 0.65rem;
  cursor: pointer;
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.character-card:hover {
  transform: translateY(-3px);
  border-color: var(--primary);
}

.character-card img {
  width: 100%;
  height: 175px;
  object-fit: cover;
  border-radius: 8px;
}

.character-card.selected {
  border: 2px solid var(--primary);
  transform: translateY(-2px) scale(1.01);
}

.character-card p {
  margin: 0.58rem 0 0.2rem;
  font-weight: 600;
}

.classroom-content {
  padding-top: 1.6rem;
}

.classroom-hero {
  margin-bottom: 1.1rem;
  background-image: linear-gradient(rgba(8, 24, 36, 0.6), rgba(8, 24, 36, 0.74)),
    url("/public/assets/Classroom_with_navigation.png");
  background-size: cover;
  background-position: center;
  min-height: 260px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.classroom-hero h1 {
  margin: 0 0 0.5rem;
}

.cta-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  margin-top: 1rem;
}

.cta-card {
  padding: 1rem;
  text-align: left;
}

.cta-card h2 {
  margin: 0 0 0.45rem;
  font-size: 1.15rem;
}

.cta-card p {
  min-height: 72px;
  color: var(--muted);
}

.panel {
  margin-top: 1rem;
  padding: 1rem 1.2rem;
}

.lessons ul {
  margin: 0;
  padding-left: 1.2rem;
}

@media (max-width: 860px) {
  .site-nav {
    justify-content: center;
  }

  .nav-links,
  .nav-auth {
    justify-content: center;
  }

  .landing-panel {
    margin-top: 2rem;
  }
}

@media (max-width: 640px) {
  .page-content {
    width: calc(100% - 1rem);
    padding-top: 1.2rem;
  }

  .hero-panel,
  .auth-panel,
  .panel,
  .cta-card {
    padding: 0.9rem;
  }

  .character-card img {
    height: 145px;
  }

  .classroom-hero {
    min-height: 220px;
  }
}