@import url('https://fonts.googleapis.com/css2?family=Noto+Sans:wght@700&family=Poppins:wght@400;500;600&display=swap');

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Poppins", sans-serif;
}

/* =========================
   Base (Mobile First)
   ========================= */

body {
  min-height: 100vh;
  background: linear-gradient(120deg, #2980b9, #8e44ad);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
}

/* Card */
.center {
  width: 100%;
  max-width: 360px;
  background: #fff;
  border-radius: 12px;
  box-shadow: 0 10px 20px rgba(0,0,0,0.08);
  overflow: hidden;
}

.center h1 {
  text-align: center;
  padding: 16px;
  font-size: 22px;
  border-bottom: 1px solid #eee;
}

/* Form */
.center form {
  padding: 20px;
}

/* Input wrapper */
.txt_field {
  position: relative;
  border-bottom: 2px solid #ccc;
  margin: 28px 0;
}

.txt_field input {
  width: 100%;
  height: 44px;
  font-size: 16px;
  border: none;
  background: none;
  outline: none;
}

/* Floating label */
.txt_field label {
  position: absolute;
  top: 50%;
  left: 4px;
  color: #999;
  transform: translateY(-50%);
  font-size: 15px;
  pointer-events: none;
  transition: 0.3s ease;
}

.txt_field span::before {
  content: "";
  position: absolute;
  left: 0;
  bottom: -2px;
  width: 0%;
  height: 2px;
  background: #2691d9;
  transition: 0.3s ease;
}

/* Active states */
.txt_field input:focus ~ label,
.txt_field input:valid ~ label {
  top: -6px;
  font-size: 13px;
  color: #2691d9;
}

.txt_field input:focus ~ span::before,
.txt_field input:valid ~ span::before {
  width: 100%;
}

/* Submit button */
input[type="submit"] {
  width: 100%;
  height: 48px;
  border: none;
  background: #2691d9;
  border-radius: 24px;
  font-size: 17px;
  color: #fff;
  font-weight: 600;
  cursor: pointer;
}

input[type="submit"]:active {
  transform: scale(0.98);
}

/* Links */
.signup_link {
  margin-top: 24px;
  text-align: center;
  font-size: 14px;
  color: #666;
}

.signup_link a {
  color: #2691d9;
  text-decoration: none;
}

.signup_link a:hover {
  text-decoration: underline;
}

/* =========================
   Tablet (≥ 600px)
   ========================= */

@media (min-width: 600px) {
  .center {
    max-width: 400px;
  }

  .center h1 {
    font-size: 24px;
    padding: 20px;
  }

  .center form {
    padding: 24px 32px;
  }
}

/* =========================
   Desktop (≥ 992px)
   ========================= */

@media (min-width: 992px) {
  body {
    padding: 0;
  }

  .center {
    max-width: 420px;
  }
}