/* --- Variables --- */
:root {
  --bg: #f5f7fa;
  --card-bg: #ffffff;
  --text: #1a1a2e;
  --text-secondary: #6b7280;
  --input-bg: #f9fafb;
  --input-border: #d1d5db;
  --input-focus: #3b82f6;
  --btn-bg: #3b82f6;
  --btn-hover: #2563eb;
  --btn-text: #ffffff;
  --error: #ef4444;
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.08);
  --logo-bg: linear-gradient(135deg, #3b82f6, #1d4ed8);
}

[data-theme="dark"] {
  --bg: #0f172a;
  --card-bg: #1e293b;
  --text: #f1f5f9;
  --text-secondary: #94a3b8;
  --input-bg: #334155;
  --input-border: #475569;
  --input-focus: #60a5fa;
  --btn-bg: #3b82f6;
  --btn-hover: #60a5fa;
  --btn-text: #ffffff;
  --error: #f87171;
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.3);
  --logo-bg: linear-gradient(135deg, #60a5fa, #3b82f6);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  transition: background-color 0.3s, color 0.3s;
}

/* --- Theme Toggle --- */
.theme-toggle {
  position: absolute;
  top: 16px;
  right: 16px;
  width: 38px;
  height: 38px;
  border-radius: 10px;
  border: 1.5px solid var(--input-border);
  background: var(--input-bg);
  cursor: pointer;
  display: flex;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.08);
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  transition: all 0.3s;
  z-index: 100;
}

.theme-toggle:hover {
  color: var(--text);
  border-color: var(--input-focus);
}

.icon-moon { display: none; }
[data-theme="dark"] .icon-sun { display: none; }
[data-theme="dark"] .icon-moon { display: block; }

/* --- Layout --- */
.login-container {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.login-card {
  position: relative;
  width: 100%;
  max-width: 400px;
  background: var(--card-bg);
  border-radius: 16px;
  padding: 48px 40px 36px;
  box-shadow: var(--shadow);
  transition: background-color 0.3s, box-shadow 0.3s;
}

/* --- Logo --- */
.logo-section {
  text-align: center;
  margin-bottom: 36px;
}

.logo-icon {
  width: 64px;
  height: 64px;
  background: var(--logo-bg);
  border-radius: 16px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 28px;
  font-weight: 700;
  color: white;
  margin-bottom: 16px;
}

.logo-section h1 {
  font-size: 24px;
  font-weight: 700;
  letter-spacing: -0.5px;
  margin-bottom: 4px;
}

.subtitle {
  color: var(--text-secondary);
  font-size: 14px;
}

/* --- Form --- */
.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 6px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.form-group input {
  width: 100%;
  padding: 12px 16px;
  font-size: 15px;
  border: 1px solid var(--input-border);
  border-radius: 10px;
  background: var(--input-bg);
  color: var(--text);
  outline: none;
  transition: all 0.2s;
}

.form-group input:focus {
  border-color: var(--input-focus);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}

.form-group input::placeholder {
  color: var(--text-secondary);
  opacity: 0.6;
}

/* --- Error --- */
.error-msg {
  background: rgba(239, 68, 68, 0.1);
  color: var(--error);
  padding: 10px 14px;
  border-radius: 8px;
  font-size: 14px;
  margin-bottom: 16px;
  border: 1px solid rgba(239, 68, 68, 0.2);
}

/* --- Button --- */
button[type="submit"] {
  width: 100%;
  padding: 13px;
  font-size: 15px;
  font-weight: 600;
  border: none;
  border-radius: 10px;
  background: var(--btn-bg);
  color: var(--btn-text);
  cursor: pointer;
  transition: all 0.2s;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  margin-top: 8px;
}

button[type="submit"]:hover:not(:disabled) {
  background: var(--btn-hover);
  transform: translateY(-1px);
}

button[type="submit"]:active:not(:disabled) {
  transform: translateY(0);
}

button[type="submit"]:disabled {
  opacity: 0.7;
  cursor: not-allowed;
}

/* --- Footer --- */
.footer-text {
  text-align: center;
  margin-top: 28px;
  font-size: 12px;
  color: var(--text-secondary);
  opacity: 0.7;
}

/* --- Responsive --- */
@media (max-width: 480px) {
  .login-card {
    padding: 36px 24px 28px;
  }
}