/* =========================
   CSS RESET
========================= */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

/* =========================
   ROOT VARIABLES
========================= */
:root {
  --bg-gradient: linear-gradient(135deg, #667eea, #764ba2);
  --card-bg: #ffffff;
  --primary: #667eea;
  --primary-hover: #5a67d8;
  --text-main: #333333;
  --text-muted: #666666;
  --border: #dddddd;
  --radius: 12px;
  --shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

/* =========================
   PAGE LAYOUT
========================= */
body {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    Roboto, Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue",
    sans-serif;
  background: var(--bg-gradient);
}

/* =========================
   LOGIN CARD
========================= */
.login-form {
  background: var(--card-bg);
  width: 320px;
  padding: 2rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

/* =========================
   HEADING
========================= */
.login-form h2 {
  text-align: center;
  margin-bottom: 1.5rem;
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-main);
}

/* =========================
   INPUT FIELDS
========================= */
.login-form input {
  width: 100%;
  padding: 0.75rem 0.85rem;
  margin-bottom: 1rem;
  font-size: 1rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text-main);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.login-form input::placeholder {
  color: var(--text-muted);
}

.login-form input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.25);
}

/* =========================
   BUTTON
========================= */
.login-form button {
  width: 100%;
  padding: 0.75rem;
  margin-top: 0.5rem;
  border: none;
  border-radius: 8px;
  background: var(--primary);
  color: white;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s ease, transform 0.1s ease,
    box-shadow 0.1s ease;
}

.login-form button:hover {
  background: var(--primary-hover);
}

.login-form button:active {
  transform: translateY(1px);
  box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15) inset;
}

/* =========================
   RESPONSIVE (MOBILE)
========================= */
@media (max-width: 400px) {
  .login-form {
    width: 90%;
    padding: 1.5rem;
  }
}