:root {
  --color-bg: #f5f7fa;
  --color-surface: #ffffff;
  --color-text: #0f172a;
  --color-text-muted: #475569;
  --color-primary: #0f766e;
  --color-primary-dark: #0b5e57;
  --color-accent: #f59e0b;
  --color-success: #16a34a;
  --color-error: #dc2626;
  --color-border: #e2e8f0;
  --radius-sm: 0.5rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.06);
  --shadow-md: 0 4px 12px rgba(15, 23, 42, 0.08);
  --space-xs: 0.5rem;
  --space-sm: 0.75rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --font-base: 1rem;
  --font-sm: 0.875rem;
  --font-lg: 1.125rem;
  --font-xl: 1.5rem;
  --font-2xl: 2rem;
}

* {
  box-sizing: border-box;
}

html {
  font-size: 18px;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", sans-serif;
  font-size: var(--font-base);
  line-height: 1.5;
  color: var(--color-text);
  background: var(--color-bg);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.topnav {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--color-primary);
  color: #fff;
  padding: 0.5rem var(--space-md);
  display: flex;
  align-items: center;
  box-shadow: var(--shadow-sm);
  min-height: 3.5rem;
}

.topnav-brand {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.15rem;
}

.brand-row {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-weight: 600;
  font-size: var(--font-lg);
}

.topnav-brand .brand-icon {
  filter: brightness(0) invert(1);
  display: block;
  width: 1.25rem;
  height: 1.25rem;
}

.brand-phone {
  font-size: 0.75rem;
  opacity: 0.75;
  padding-left: calc(1.25rem + 0.4rem);
  white-space: nowrap;
}

.brand-phone[hidden] {
  display: none;
}

.nav-signin,
.nav-signout {
  color: rgba(255, 255, 255, 0.8);
  text-decoration: none;
  font-size: 0.8125rem;
  font-weight: 500;
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius-sm);
  transition: background 0.15s;
  white-space: nowrap;
  margin-left: auto;
}

.nav-signin:hover,
.nav-signout:hover {
  background: rgba(255, 255, 255, 0.12);
  color: #fff;
}

.nav-signin[hidden],
.nav-signout[hidden] {
  display: none;
}

.container {
  flex: 1;
  width: 100%;
  max-width: 28rem;
  margin: 0 auto;
  padding: var(--space-lg) var(--space-md);
}

.screen {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-xl) var(--space-lg);
  box-shadow: var(--shadow-md);
  margin-bottom: var(--space-lg);
  animation: fadeIn 0.25s ease-out;
}

.screen-title {
  margin: 0 0 var(--space-sm);
  font-size: var(--font-2xl);
  font-weight: 700;
  letter-spacing: -0.01em;
}

.screen-text {
  margin: 0 0 var(--space-lg);
  color: var(--color-text-muted);
}

.screen-error {
  border: 2px solid var(--color-error);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-xs);
  border: 0;
  cursor: pointer;
  font-size: var(--font-base);
  font-weight: 600;
  padding: 0.75rem 1.25rem;
  border-radius: var(--radius-md);
  min-height: 3rem;
  transition: background-color 0.15s ease, transform 0.05s ease;
}

.btn:active {
  transform: scale(0.98);
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
}

.btn-primary:hover,
.btn-primary:focus-visible {
  background: var(--color-primary-dark);
  outline: none;
}

.btn-ghost {
  background: transparent;
  color: var(--color-primary);
  border: 1px solid var(--color-border);
}

.btn-block {
  width: 100%;
  margin-top: var(--space-md);
}

.btn:disabled {
  opacity: 0.7;
  cursor: not-allowed;
}

.plan-list {
  display: grid;
  gap: var(--space-md);
  margin-bottom: var(--space-md);
}

.plan-card {
  background: var(--color-bg);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  cursor: pointer;
  transition: border-color 0.15s ease, transform 0.05s ease;
}

.plan-card:hover,
.plan-card:focus-within {
  border-color: var(--color-primary);
}

.plan-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: var(--space-xs);
}

.plan-name {
  margin: 0;
  font-size: var(--font-lg);
  font-weight: 700;
}

.plan-price {
  font-size: var(--font-xl);
  font-weight: 700;
  color: var(--color-primary);
}

.plan-features {
  list-style: none;
  padding: 0;
  margin: var(--space-sm) 0 var(--space-md);
  color: var(--color-text-muted);
  font-size: var(--font-sm);
}

.plan-features li {
  padding: 0.25rem 0;
}

.plan-card-free {
  border-color: var(--color-accent);
  background: linear-gradient(135deg, rgba(245, 158, 11, 0.05), rgba(245, 158, 11, 0.02));
}

.plan-card-free .plan-price {
  color: var(--color-success);
  font-size: 1.25rem;
}

.form {
  display: grid;
  gap: var(--space-md);
  margin-bottom: var(--space-md);
}

.field {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.field-label {
  font-size: var(--font-sm);
  font-weight: 600;
  color: var(--color-text-muted);
}

.field-error {
  color: var(--color-error);
  font-size: var(--font-sm);
  text-align: center;
  padding: var(--space-sm);
  background: rgba(220, 38, 38, 0.05);
  border-radius: var(--radius-sm);
  margin: 0;
}

.field-error a {
  color: var(--color-primary);
  font-weight: 600;
  text-decoration: underline;
}

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

.input {
  width: 100%;
  padding: 0.75rem 1rem;
  font-size: var(--font-lg);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  min-height: 3rem;
  font-family: inherit;
}

.input:focus {
  outline: none;
  border-color: var(--color-primary);
}

.pin-boxes {
  display: flex;
  gap: 0.75rem;
  justify-content: center;
}

.pin-digit {
  width: 3.25rem;
  height: 3.5rem;
  text-align: center;
  font-size: 1.5rem;
  font-weight: 700;
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  font-family: inherit;
  caret-color: transparent;
}

.pin-digit:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(15, 118, 110, 0.15);
}

.pin-digit.filled {
  background: var(--color-bg);
  border-color: var(--color-primary);
}

.plan-summary {
  background: var(--color-bg);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  margin-bottom: var(--space-lg);
}

.plan-summary dl {
  margin: 0;
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.5rem var(--space-md);
}

.plan-summary dt {
  color: var(--color-text-muted);
  font-size: var(--font-sm);
}

.plan-summary dd {
  margin: 0;
  font-weight: 600;
}

.current-session {
  background: linear-gradient(135deg, var(--color-primary) 0%, #0b5e57 100%);
  color: #fff;
  border-radius: var(--radius-md);
  padding: var(--space-md);
  margin-bottom: var(--space-md);
}

.current-session-head {
  font-weight: 700;
  font-size: var(--font-sm);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  opacity: 0.85;
  margin-bottom: var(--space-sm);
}

.current-session-row {
  display: flex;
  justify-content: space-between;
  padding: 0.35rem 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.15);
  font-size: var(--font-sm);
}

.current-session-row:last-child {
  border-bottom: 0;
}

.session-expiry {
  font-weight: 700;
}

.spinner-inline {
  display: inline-block;
  width: 1.125rem;
  height: 1.125rem;
  border: 2px solid rgba(255,255,255,0.3);
  border-top-color: #fff;
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}

.spinner {
  width: 3rem;
  height: 3rem;
  border: 4px solid var(--color-border);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  margin: 0 auto var(--space-md);
  animation: spin 0.9s linear infinite;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

.muted {
  color: var(--color-text-muted);
  font-size: var(--font-sm);
  text-align: center;
  margin-top: var(--space-md);
}

.form-links {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
  margin-top: var(--space-md);
  text-align: center;
}

.form-links a {
  color: var(--color-primary);
  text-decoration: none;
  font-weight: 600;
  font-size: var(--font-sm);
  padding: 0.5rem 0;
  display: inline-block;
  transition: opacity 0.15s ease;
}

.form-links a:hover,
.form-links a:focus-visible {
  opacity: 0.75;
  outline: none;
}

.pulse-text {
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(0.5rem); }
  to { opacity: 1; transform: translateY(0); }
}

.app-footer {
  text-align: center;
  padding: var(--space-md);
  color: var(--color-text-muted);
  font-size: var(--font-sm);
}

.app-footer a {
  color: var(--color-primary);
  text-decoration: none;
  font-weight: 600;
}

.inline-voucher {
  display: flex;
  gap: 0.5rem;
  margin-bottom: var(--space-md);
}

.inline-voucher .input {
  flex: 1;
  min-width: 0;
}

.instruction-bold {
  font-weight: 700;
  font-size: var(--font-lg);
  text-align: center;
  margin-bottom: var(--space-md);
}

@media (max-width: 320px) {
  html {
    font-size: 16px;
  }
  .topnav {
    padding: 0.375rem var(--space-sm);
    min-height: 3rem;
  }
  .brand-row {
    font-size: 1rem;
  }
  .pin-digit {
    width: 2.75rem;
    height: 3rem;
    font-size: 1.25rem;
  }
  .plan-list {
    gap: var(--space-sm);
  }
}

@media (min-width: 375px) {
  .pin-digit {
    width: 3.5rem;
    height: 3.75rem;
    font-size: 1.75rem;
  }
  .pin-boxes {
    gap: 0.875rem;
  }
}

@media (min-width: 420px) {
  .pin-digit {
    width: 3.75rem;
    height: 4rem;
    font-size: 2rem;
  }
  .pin-boxes {
    gap: 1rem;
  }
}

@media (min-width: 768px) {
  html {
    font-size: 16px;
  }
  .container {
    max-width: 32rem;
  }
  .screen {
    padding: var(--space-2xl) var(--space-xl);
  }
  .pin-digit {
    width: 4rem;
    height: 4.25rem;
    font-size: 2rem;
  }
  .plan-list {
    grid-template-columns: 1fr 1fr;
  }
}

@media (min-width: 1024px) {
  .container {
    max-width: 36rem;
  }
  .screen-title {
    font-size: 2.5rem;
  }
}

@media (min-width: 1440px) {
  .container {
    max-width: 40rem;
  }
}

.status-banner {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.625rem var(--space-md);
  border-radius: var(--radius-md);
  font-size: var(--font-sm);
  font-weight: 600;
  margin-bottom: var(--space-md);
}
.status-banner.connected {
  background: rgba(22, 163, 74, 0.1);
  color: var(--color-success);
  border: 1px solid rgba(22, 163, 74, 0.2);
}
.status-banner.ended {
  background: rgba(245, 158, 11, 0.1);
  color: #92400e;
  border: 1px solid rgba(245, 158, 11, 0.2);
}
.status-icon {
  font-size: var(--font-lg);
  line-height: 1;
}