:root {
  --black: #000000;
  --white: #ffffff;
  --gray-100: #f5f5f5;
  --gray-300: #d4d4d4;
  --gray-500: #737373;
  --gray-700: #404040;
  --border: 1px solid var(--black);
  --radius: 4px;
  --font: "IBM Plex Sans", "Segoe UI", "Helvetica Neue", Arial, sans-serif;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  min-height: 100%;
  background: var(--white);
  color: var(--black);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--black);
  text-decoration: underline;
  text-underline-offset: 3px;
}

a:hover {
  color: var(--gray-700);
}

.site-header {
  border-bottom: var(--border);
  padding: 1rem 1.25rem;
}

.brand {
  font-weight: 600;
  letter-spacing: -0.02em;
  text-decoration: none;
}

.brand:hover {
  color: var(--black);
}

.page {
  width: 100%;
  max-width: 420px;
  margin: 0 auto;
  padding: 3rem 1.25rem 4rem;
}

.page-title {
  margin: 0 0 0.5rem;
  font-size: 1.75rem;
  font-weight: 600;
  letter-spacing: -0.03em;
}

.page-subtitle {
  margin: 0 0 2rem;
  color: var(--gray-500);
  font-size: 0.95rem;
}

.form {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.field {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.field label {
  font-size: 0.875rem;
  font-weight: 500;
}

.input-wrap {
  position: relative;
  display: flex;
  align-items: center;
}

.field input {
  width: 100%;
  padding: 0.75rem 0.85rem;
  border: var(--border);
  border-radius: var(--radius);
  background: var(--white);
  color: var(--black);
  font-family: inherit;
  font-size: 1rem;
  outline: none;
}

.field input:focus {
  background: var(--gray-100);
}

.field input.has-toggle {
  padding-right: 2.75rem;
}

.field input.invalid {
  border-color: var(--black);
  background: var(--gray-100);
}

.toggle-password {
  position: absolute;
  right: 0.35rem;
  top: 50%;
  transform: translateY(-50%);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.25rem;
  height: 2.25rem;
  padding: 0;
  border: none;
  background: transparent;
  color: var(--black);
  cursor: pointer;
}

.toggle-password:hover {
  color: var(--gray-700);
}

.toggle-password svg {
  display: block;
  width: 1.25rem;
  height: 1.25rem;
  stroke: currentColor;
  fill: none;
  stroke-width: 1.75;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.toggle-password svg[hidden] {
  display: none;
}

.toggle-password .icon-eye circle,
.toggle-password .icon-eye-off circle {
  fill: currentColor;
  stroke: none;
}

.toggle-password .eye-slash {
  stroke-width: 2.25;
}

.hint {
  margin: 0;
  font-size: 0.8rem;
  color: var(--gray-500);
}

.hint-break {
  margin-top: 1rem;
  word-break: break-all;
}

.hint.ok {
  color: var(--gray-700);
}

.error {
  margin: 0;
  min-height: 1.1em;
  font-size: 0.8rem;
  color: var(--black);
  font-weight: 500;
}

.form-error {
  margin: 0;
  padding: 0.75rem 0.85rem;
  border: var(--border);
  border-radius: var(--radius);
  background: var(--gray-100);
  font-size: 0.875rem;
}

.form-error[hidden],
.error:empty {
  display: none;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  min-height: 2.75rem;
  padding: 0.75rem 1rem;
  border: var(--border);
  border-radius: var(--radius);
  background: var(--black);
  color: var(--white);
  font-family: inherit;
  font-size: 0.95rem;
  font-weight: 500;
  cursor: pointer;
}

.btn:hover:not(:disabled) {
  background: var(--gray-700);
}

.btn:disabled {
  background: var(--gray-500);
  border-color: var(--gray-500);
  cursor: not-allowed;
}

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

.btn-secondary:hover:not(:disabled) {
  background: var(--gray-100);
}

.form-footer {
  margin-top: 0.5rem;
  text-align: center;
  font-size: 0.9rem;
  color: var(--gray-700);
}

.form-success {
  margin: 0;
  padding: 0.75rem 0.85rem;
  border: var(--border);
  border-radius: var(--radius);
  background: var(--gray-100);
  font-size: 0.875rem;
}

.form-success[hidden] {
  display: none;
}

.profile-avatar-block {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  margin-bottom: 1.75rem;
}

.avatar-preview {
  position: relative;
  width: 5.5rem;
  height: 5.5rem;
  border: var(--border);
  border-radius: 50%;
  overflow: hidden;
  flex-shrink: 0;
  background: var(--gray-100);
  display: flex;
  align-items: center;
  justify-content: center;
}

.avatar-preview img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.avatar-preview img[hidden] {
  display: none;
}

.avatar-fallback {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--gray-700);
}

.avatar-actions {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  min-width: 0;
}

.btn-file {
  width: auto;
  min-height: 2.25rem;
  padding: 0.5rem 0.9rem;
  cursor: pointer;
}

.field input[readonly] {
  background: var(--gray-100);
  color: var(--gray-700);
}

.profile-actions {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin-top: 0.25rem;
}

.btn-danger {
  background: var(--white);
  color: var(--black);
  border-style: dashed;
}

.btn-danger:hover:not(:disabled) {
  background: var(--gray-100);
}

.danger-zone {
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  border-top: var(--border);
}

.danger-title {
  margin: 0 0 0.5rem;
  font-size: 1rem;
  font-weight: 600;
}

.delete-confirm {
  margin-top: 1rem;
}

#delete-form[hidden] {
  display: none;
}

.account-card {
  border: var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  margin: 0 0 1.5rem;
}

#profile-view[hidden],
#profile-form[hidden],
#avatar-actions[hidden] {
  display: none;
}

.account-row {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  margin-bottom: 1rem;
}

.account-row:last-child {
  margin-bottom: 0;
}

.account-label {
  font-size: 0.8rem;
  color: var(--gray-500);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.account-value {
  font-size: 0.95rem;
  word-break: break-all;
}

@media (min-width: 640px) {
  .page {
    padding-top: 4.5rem;
  }

  .page-title {
    font-size: 2rem;
  }
}

.security-zone {
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  border-top: var(--border);
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.security-zone[hidden] {
  display: none;
}

.security-subtitle {
  margin: 0.5rem 0 0;
  font-size: 0.95rem;
  font-weight: 600;
}

.security-form {
  padding-top: 1rem;
  border-top: var(--border);
}

.checkbox-field[hidden] {
  display: none;
}

.checkbox-label {
  display: flex;
  align-items: flex-start;
  gap: 0.6rem;
  font-size: 0.875rem;
  line-height: 1.4;
  cursor: pointer;
}

.checkbox-label input[type="checkbox"] {
  width: 1.1rem;
  height: 1.1rem;
  margin-top: 0.15rem;
  flex-shrink: 0;
  accent-color: var(--black);
}

/* 2FA и устройства */
.security-block {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  padding-top: 1rem;
  border-top: var(--border);
}

.security-block [hidden] {
  display: none;
}

.twofa-qr {
  display: block;
  width: 192px;
  height: 192px;
  border: var(--border);
  border-radius: var(--radius);
  image-rendering: pixelated;
}

.twofa-secret {
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.85rem;
  word-break: break-all;
  background: var(--gray-100);
  padding: 0.15rem 0.35rem;
  border-radius: var(--radius);
}

.backup-codes {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.4rem 1rem;
  margin: 0;
  padding: 1rem;
  list-style: none;
  border: var(--border);
  border-radius: var(--radius);
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.95rem;
}

.sessions-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.session-item {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  padding: 0.85rem 1rem;
  border: var(--border);
  border-radius: var(--radius);
}

.session-meta {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
  min-width: 0;
}

.session-name {
  font-weight: 600;
  font-size: 0.95rem;
}

.session-badge {
  display: inline-block;
  margin-left: 0.4rem;
  padding: 0.05rem 0.4rem;
  border: var(--border);
  border-radius: var(--radius);
  font-size: 0.7rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.session-details {
  font-size: 0.8rem;
  color: var(--gray-500);
}

/* CAPTCHA (чёрно-белая; появляется только после нескольких неудач) */
.captcha {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  padding: 0.85rem 1rem;
  border: var(--border);
  border-radius: var(--radius);
  background: var(--white);
}

.captcha[hidden],
.captcha-altcha[hidden],
.captcha-turnstile[hidden] {
  display: none;
}

.captcha-title {
  margin: 0;
  font-size: 0.875rem;
  font-weight: 600;
}

.captcha-altcha {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.captcha-btn:disabled {
  background: var(--black);
  color: var(--white);
  opacity: 1;
}

.captcha-status {
  font-size: 0.8rem;
  color: var(--gray-700);
}

/* Уведомление (например, о согласии родителей) */
.notice {
  margin: 0 0 0.5rem;
  padding: 0.65rem 0.85rem;
  border: var(--border);
  border-radius: var(--radius);
  background: var(--gray-100);
  font-size: 0.8rem;
  line-height: 1.4;
}

.field[hidden] {
  display: none;
}

/* Альтернативные способы входа: Passkey и ссылка из письма */
.alt-login {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin-top: 1rem;
}

.alt-login[hidden] {
  display: none;
}