:root {
  --color-charcoal: #36454f;
  --color-charcoal-light: #576673;
  --color-charcoal-dark: #232e36;
  --color-red: #e63946;

  --color-white: #ffffff;
  --color-off-white: #f8f9fa;
  --color-light-gray: #e9ecef;
  --color-gray: #ced4da;
  --color-dark-gray: #6c757d;
  --color-black: #212529;

  --color-success: #28a745;
  --color-warning: #ffc107;
  --color-error: #dc3545;
  --color-info: #17a2b8;

  --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-secondary: 'Georgia', serif;
  --font-mono: 'Courier New', monospace;

  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.5rem;
  --space-6: 2rem;
  --space-7: 3rem;

  --radius-sm: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 1rem;
  --radius-pill: 999px;

  --shadow-sm: 0 2px 4px rgba(0,0,0,0.08);
  --shadow-md: 0 8px 24px rgba(0,0,0,0.10);
  --shadow-lg: 0 20px 40px rgba(0,0,0,0.14);

  --container: 1200px;
  --container-narrow: 960px;

  --transition-fast: 0.15s ease;
  --transition-normal: 0.3s ease;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-primary);
  color: var(--color-black);
  background: var(--color-off-white);
  line-height: 1.5;
}

img,
svg,
video {
  display: block;
  max-width: 100%;
}

a {
  color: var(--color-charcoal);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-red);
}

button,
input,
textarea,
select {
  font: inherit;
}

h1, h2, h3, h4, h5, h6 {
  margin: 0 0 var(--space-4);
  line-height: 1.2;
  color: var(--color-charcoal);
}

p {
  margin: 0 0 var(--space-4);
}

ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

:focus {
  outline: none;
}

/* layout */
.container {
  width: min(100% - 2rem, var(--container));
  margin-inline: auto;
}

.container-narrow {
  width: min(100% - 2rem, var(--container-narrow));
  margin-inline: auto;
}

.section {
  padding-block: var(--space-7);
}

.stack > * + * {
  margin-top: var(--space-4);
}

.cluster {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-3);
}

.split {
  display: grid;
  gap: var(--space-6);
}

.split-2 {
  grid-template-columns: 1fr 1fr;
}

@media (max-width: 992px) {
  .split-2 {
    grid-template-columns: 1fr;
  }
}

/* site chrome */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--color-white);
  box-shadow: var(--shadow-sm);
}

.site-header-bar {
  min-height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}

.site-brand {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--color-charcoal);
}

.checkmark {
  color: var(--color-red);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.site-nav a {
  font-weight: 500;
}

.site-footer {
  margin-top: var(--space-7);
  background: linear-gradient(135deg, #1f2937 0%, #111827 100%);
  color: #d1d5db;
  border-top: 1px solid #374151;
}

.site-footer a {
  color: #93c5fd;
}

.site-footer a:hover {
  color: #dbeafe;
  text-decoration: underline;
}

.site-footer .site-brand {
  color: #ffffff;
}

.site-footer .checkmark {
  color: var(--color-red);
}

.site-footer-inner {
  padding: var(--space-6) 0;
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: var(--space-5);
}

.site-footer-label {
  display: block;
  margin-bottom: var(--space-2);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: #9ca3af;
}

.site-footer-copy {
  color: #d1d5db;
}

.site-footer-bottom {
  border-top: 1px solid #374151;
  padding: var(--space-3) 0;
}

.site-footer-bottom p {
  margin: 0;
  color: #9ca3af;
  font-size: 0.875rem;
}

@media (max-width: 768px) {
  .site-footer-inner {
    grid-template-columns: 1fr;
    gap: var(--space-4);
    text-align: center;
    justify-items: center;
  }

  .site-footer-inner > div {
    display: flex;
    flex-direction: column;
    align-items: center;
  }

  .site-footer-bottom,
  .site-footer-bottom p {
    text-align: center;
  }
}

/* components */
.panel {
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-md);
}

.panel-light {
  background: var(--color-white);
  color: var(--color-black);
}

.panel-dark {
  background: linear-gradient(to right, #1e272e 0%, #36454f 100%);
  color: var(--color-white);
}

.panel-dark h1,
.panel-dark h2,
.panel-dark h3,
.panel-dark p {
  color: var(--color-white);
}

.card {
  background: var(--color-white);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  padding: var(--space-5);
}

.notice {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-4);
  background: var(--color-off-white);
  border-radius: var(--radius-md);
}

.feature-list {
  display: grid;
  gap: var(--space-4);
}

.feature {
  display: grid;
  grid-template-columns: 40px 1fr;
  gap: var(--space-3);
  align-items: start;
}

.feature-badge {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  background: rgba(255,255,255,0.14);
  box-shadow: var(--shadow-sm);
}

.feature-copy h3 {
  margin-bottom: var(--space-1);
  font-size: 1.125rem;
}

.hero-art {
  text-align: center;
}

.hero-art img {
  max-height: 300px;
  margin-inline: auto;
}

/* forms */
.auth-card {
  width: min(100%, 450px);
  margin-inline: auto;
}

.form-group {
  margin-bottom: var(--space-5);
}

.form-label {
  display: block;
  margin-bottom: var(--space-2);
  font-weight: 600;
  color: var(--color-charcoal);
}

.form-control {
  width: 100%;
  padding: 0.8rem 1rem;
  border: 2px solid var(--color-gray);
  border-radius: var(--radius-sm);
  background: var(--color-white);
  color: var(--color-black);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.form-control:focus {
  border-color: var(--color-charcoal);
  box-shadow: 0 0 0 0.2rem rgba(54, 69, 79, 0.2);
  outline: 0;
}

.form-control:disabled {
  background: var(--color-light-gray);
  color: var(--color-dark-gray);
}

.form-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-3);
}

@media (max-width: 576px) {
  .form-row {
    flex-direction: column;
    align-items: flex-start;
  }
}

.form-help {
  font-size: 0.875rem;
  color: var(--color-dark-gray);
  margin-top: var(--space-2);
}

.form-toggle {
  background: none;
  border: none;
  padding: 0;
  color: var(--color-charcoal);
  cursor: pointer;
  font-size: 0.875rem;
}

.form-toggle:hover {
  color: var(--color-red);
  text-decoration: underline;
}

.message {
  padding: 0.75rem 1rem;
  border-radius: var(--radius-sm);
  text-align: center;
}

.message-error {
  background: rgba(220, 53, 69, 0.10);
  color: #b42318;
}

.message-success {
  background: rgba(40, 167, 69, 0.10);
  color: #1f7a36;
}

/* buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: 0.7rem 1.15rem;
  border: 2px solid transparent;
  border-radius: var(--radius-sm);
  font-weight: 600;
  cursor: pointer;
  transition: transform var(--transition-fast),
              background var(--transition-fast),
              border-color var(--transition-fast),
              color var(--transition-fast),
              box-shadow var(--transition-fast);
}

.btn:disabled {
  opacity: 0.65;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--color-charcoal);
  border-color: var(--color-charcoal);
  color: var(--color-white);
}

.btn-primary:hover {
  background: var(--color-charcoal-dark);
  border-color: var(--color-charcoal-dark);
  color: var(--color-white);
}

/* Shared hover: subtle scale + lift, no ring */
.btn:hover:not(:disabled) {
  transform: translateY(-1px) scale(1.02);
  box-shadow: var(--shadow-sm);
}

/* Active: slight press down */
.btn:active:not(:disabled) {
  transform: translateY(0) scale(0.99);
  box-shadow: none;
}

button:focus-visible,
.btn:focus-visible {
  outline: none;
  box-shadow: 0 0 0 2px rgba(54, 69, 79, 0.15);
}

.btn-danger {
  background: var(--color-red);
  border-color: var(--color-red);
  color: var(--color-white);
}

.btn-block {
  width: 100%;
}

.badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.35rem 0.65rem;
  border-radius: var(--radius-pill);
  font-size: 0.75rem;
  font-weight: 700;
  line-height: 1;
}

.badge-primary {
  background: var(--color-charcoal);
  color: var(--color-white);
}

/* utilities */
.text-center { text-align: center; }
.text-small { font-size: 0.875rem; }
.text-muted { color: var(--color-dark-gray); }
.text-bold { font-weight: 700; }
.w-100 { width: 100%; }

.mt-1 { margin-top: var(--space-2); }
.mt-2 { margin-top: var(--space-4); }
.mt-3 { margin-top: var(--space-5); }
.mt-4 { margin-top: var(--space-6); }

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: var(--space-2); }
.mb-2 { margin-bottom: var(--space-4); }
.mb-3 { margin-bottom: var(--space-5); }
.mb-4 { margin-bottom: var(--space-6); }

@media (prefers-color-scheme: dark) {
  :root {
    --color-white: #1e1e1e;
    --color-off-white: #2d2d2d;
    --color-light-gray: #3a3a3a;
    --color-gray: #555555;
    --color-dark-gray: #aaaaaa;
    --color-black: #eeeeee;
    --color-red: #ff5252;
    --color-charcoal: #90a4ae;
    --color-charcoal-light: #b0bec5;
    --color-charcoal-dark: #78909c;
  }
}