:root {
  color-scheme: light;
  --bg: #eef4ff;
  --ink: #172133;
  --muted: #5f6f85;
  --card: rgba(255, 255, 255, 0.92);
  --line: rgba(23, 33, 51, 0.14);
  --accent: #156ad8;
  --plastic-hi: #2d86f3;
  --plastic-low: #0f54b4;
  --plastic-shadow: rgba(4, 24, 56, 0.48);
  --plastic-glow: rgba(21, 106, 216, 0.28);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px;
  font-family: "Nunito", "Segoe UI", Tahoma, sans-serif;
  color: var(--ink);
  background:
    radial-gradient(circle at 10% 10%, #d7e9ff 0, rgba(215, 233, 255, 0) 40%),
    radial-gradient(circle at 88% 90%, #e1f2ff 0, rgba(225, 242, 255, 0) 46%),
    linear-gradient(150deg, #f7fbff 0%, var(--bg) 100%);
}

.card {
  width: min(540px, 100%);
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 22px;
  padding: 30px 24px;
  box-shadow: 0 20px 48px rgba(8, 22, 48, 0.18);
}

h1 {
  margin: 0 0 8px;
  font-size: clamp(1.8rem, 5vw, 2.6rem);
  letter-spacing: -0.02em;
}

.sub {
  margin: 0 0 20px;
  color: var(--muted);
  line-height: 1.55;
}

.field {
  margin-bottom: 12px;
}

label {
  display: block;
  margin-bottom: 6px;
  font-size: 0.86rem;
  font-weight: 700;
  color: #25423d;
}

input {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 11px 12px;
  font-size: 1rem;
}

.actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-top: 8px;
}

.btn {
  border: 1px solid rgba(255, 255, 255, 0.3);
  border-radius: 14px;
  padding: 10px 14px;
  font-weight: 700;
  cursor: pointer;
  color: #fff;
  background: linear-gradient(180deg, var(--plastic-hi), var(--plastic-low));
  box-shadow:
    0 7px 0 var(--plastic-shadow),
    0 14px 24px var(--plastic-glow),
    inset 0 1px 0 rgba(255, 255, 255, 0.38);
  transition: transform 140ms ease, box-shadow 180ms ease, filter 180ms ease;
  text-decoration: none;
}

.btn-main {
  background: linear-gradient(180deg, var(--plastic-hi), var(--plastic-low));
}

.btn-ghost {
  border-color: rgba(255, 255, 255, 0.3);
  background: linear-gradient(180deg, var(--plastic-hi), var(--plastic-low));
  color: #fff;
}

.btn:active {
  transform: translateY(3px);
  box-shadow:
    0 4px 0 var(--plastic-shadow),
    0 9px 16px var(--plastic-glow),
    inset 0 1px 0 rgba(255, 255, 255, 0.34);
}

.msg {
  margin-top: 14px;
  font-size: 0.92rem;
  color: #20514a;
  min-height: 1.35em;
}

.session-card {
  margin-top: 16px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.78);
}

.session-card p {
  margin: 0;
}

@media (max-width: 640px) {
  body {
    padding: 12px;
  }

  .card {
    padding: 20px 14px;
    border-radius: 18px;
  }
}