/* Septober 2026 Modern Stylesheet
 * Guided by modern-web-guidance:
 * - dark-mode: CSS custom properties, light-dark(), color-scheme
 * - improve-text-layout-and-legibility: text-wrap balance and pretty
 * - Accessible focus rings, modern surface tokens, and responsive layout
 */

:root {
  --font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;

  /* Theme Tokens - Light */
  --bg-light: #f8fafc;
  --surface-light: #ffffff;
  --surface-subtle-light: #f1f5f9;
  --surface-hover-light: #e2e8f0;
  --border-light: #cbd5e1;
  --border-subtle-light: #e2e8f0;
  --text-main-light: #0f172a;
  --text-muted-light: #64748b;
  --primary-light: #4f46e5;
  --primary-hover-light: #4338ca;
  --primary-subtle-light: #eef2ff;
  --danger-light: #dc2626;
  --danger-bg-light: #fef2f2;
  --warning-light: #d97706;
  --warning-bg-light: #fffbeb;
  --success-light: #16a34a;
  --success-bg-light: #f0fdf4;
  --shadow-light: 0 4px 20px -2px rgba(15, 23, 42, 0.08), 0 2px 6px -1px rgba(15, 23, 42, 0.04);

  /* Theme Tokens - Dark */
  --bg-dark: #0b0f19;
  --surface-dark: #121826;
  --surface-subtle-dark: #1e2638;
  --surface-hover-dark: #2a354d;
  --border-dark: #273349;
  --border-subtle-dark: #1d2638;
  --text-main-dark: #f8fafc;
  --text-muted-dark: #94a3b8;
  --primary-dark: #6366f1;
  --primary-hover-dark: #818cf8;
  --primary-subtle-dark: #1e1b4b;
  --danger-dark: #f87171;
  --danger-bg-dark: #450a0a;
  --warning-dark: #fbbf24;
  --warning-bg-dark: #451a03;
  --success-dark: #4ade80;
  --success-bg-dark: #052e16;
  --shadow-dark: 0 4px 24px -2px rgba(0, 0, 0, 0.5), 0 2px 8px -1px rgba(0, 0, 0, 0.3);

  /* Active Theme Defaults: DARK FIRST */
  --bg: var(--bg-dark);
  --surface: var(--surface-dark);
  --surface-subtle: var(--surface-subtle-dark);
  --surface-hover: var(--surface-hover-dark);
  --border: var(--border-dark);
  --border-subtle: var(--border-subtle-dark);
  --text-main: var(--text-main-dark);
  --text-muted: var(--text-muted-dark);
  --primary: var(--primary-dark);
  --primary-hover: var(--primary-hover-dark);
  --primary-subtle: var(--primary-subtle-dark);
  --danger: var(--danger-dark);
  --danger-bg: var(--danger-bg-dark);
  --warning: var(--warning-dark);
  --warning-bg: var(--warning-bg-dark);
  --success: var(--success-dark);
  --success-bg: var(--success-bg-dark);
  --shadow: var(--shadow-dark);

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;

  accent-color: var(--primary);
  color-scheme: dark light;
  scrollbar-color: var(--border) transparent;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: var(--bg-light);
    --surface: var(--surface-light);
    --surface-subtle: var(--surface-subtle-light);
    --surface-hover: var(--surface-hover-light);
    --border: var(--border-light);
    --border-subtle: var(--border-subtle-light);
    --text-main: var(--text-main-light);
    --text-muted: var(--text-muted-light);
    --primary: var(--primary-light);
    --primary-hover: var(--primary-hover-light);
    --primary-subtle: var(--primary-subtle-light);
    --danger: var(--danger-light);
    --danger-bg: var(--danger-bg-light);
    --warning: var(--warning-light);
    --warning-bg: var(--warning-bg-light);
    --success: var(--success-light);
    --success-bg: var(--success-bg-light);
    --shadow: var(--shadow-light);
  }
}

@supports (color: light-dark(white, black)) {
  :root {
    --bg: light-dark(var(--bg-light), var(--bg-dark));
    --surface: light-dark(var(--surface-light), var(--surface-dark));
    --surface-subtle: light-dark(var(--surface-subtle-light), var(--surface-subtle-dark));
    --surface-hover: light-dark(var(--surface-hover-light), var(--surface-hover-dark));
    --border: light-dark(var(--border-light), var(--border-dark));
    --border-subtle: light-dark(var(--border-subtle-light), var(--border-subtle-dark));
    --text-main: light-dark(var(--text-main-light), var(--text-main-dark));
    --text-muted: light-dark(var(--text-muted-light), var(--text-muted-dark));
    --primary: light-dark(var(--primary-light), var(--primary-dark));
    --primary-hover: light-dark(var(--primary-hover-light), var(--primary-hover-dark));
    --primary-subtle: light-dark(var(--primary-subtle-light), var(--primary-subtle-dark));
    --danger: light-dark(var(--danger-light), var(--danger-dark));
    --danger-bg: light-dark(var(--danger-bg-light), var(--danger-bg-dark));
    --warning: light-dark(var(--warning-light), var(--warning-dark));
    --warning-bg: light-dark(var(--warning-bg-light), var(--warning-bg-dark));
    --success: light-dark(var(--success-light), var(--success-dark));
    --success-bg: light-dark(var(--success-bg-light), var(--success-bg-dark));
    --shadow: light-dark(var(--shadow-light), var(--shadow-dark));
  }
}

html[data-theme='light'],
body[data-theme='light'] {
  --bg: var(--bg-light);
  --surface: var(--surface-light);
  --surface-subtle: var(--surface-subtle-light);
  --surface-hover: var(--surface-hover-light);
  --border: var(--border-light);
  --border-subtle: var(--border-subtle-light);
  --text-main: var(--text-main-light);
  --text-muted: var(--text-muted-light);
  --primary: var(--primary-light);
  --primary-hover: var(--primary-hover-light);
  --primary-subtle: var(--primary-subtle-light);
  --danger: var(--danger-light);
  --danger-bg: var(--danger-bg-light);
  --warning: var(--warning-light);
  --warning-bg: var(--warning-bg-light);
  --success: var(--success-light);
  --success-bg: var(--success-bg-light);
  --shadow: var(--shadow-light);
  color-scheme: light;
}

html[data-theme='dark'],
body[data-theme='dark'] {
  --bg: var(--bg-dark);
  --surface: var(--surface-dark);
  --surface-subtle: var(--surface-subtle-dark);
  --surface-hover: var(--surface-hover-dark);
  --border: var(--border-dark);
  --border-subtle: var(--border-subtle-dark);
  --text-main: var(--text-main-dark);
  --text-muted: var(--text-muted-dark);
  --primary: var(--primary-dark);
  --primary-hover: var(--primary-hover-dark);
  --primary-subtle: var(--primary-subtle-dark);
  --danger: var(--danger-dark);
  --danger-bg: var(--danger-bg-dark);
  --warning: var(--warning-dark);
  --warning-bg: var(--warning-bg-dark);
  --success: var(--success-dark);
  --success-bg: var(--success-bg-dark);
  --shadow: var(--shadow-dark);
  color-scheme: dark;
}

* {
  box-sizing: border-box;
}

body {
  background-color: var(--bg);
  color: var(--text-main);
  font-family: var(--font-family);
  font-size: 15px;
  line-height: 1.55;
  margin: 0;
  padding: 0 1rem 3rem;
  transition: background-color 0.2s ease, color 0.2s ease;
  -webkit-font-smoothing: antialiased;
}

h1 {
  font-size: 2.25rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.2;
  margin: 0.5rem 0 1rem;
  text-wrap: balance;
}

/* Flashy page title */
#container > h1 {
  background: linear-gradient(135deg, var(--text-main) 30%, var(--primary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
  filter: drop-shadow(0 2px 8px rgba(99, 102, 241, 0.25));
  font-size: 2.5rem;
  font-weight: 900;
  letter-spacing: -0.03em;
  margin-bottom: 1.25rem;
}

h2 {
  color: var(--text-main);
  font-size: 1.65rem;
  font-weight: 750;
  letter-spacing: -0.02em;
  margin: 0.5rem 0 0.75rem;
  text-wrap: balance;
}

h3, h4, h5, h6 {
  color: var(--text-main);
  font-weight: 700;
  letter-spacing: -0.015em;
  margin: 0.5rem 0 0.75rem;
  text-wrap: balance;
}

/* Theme Toggle Button */
.theme-toggle {
  align-items: center;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 9999px;
  bottom: 1.25rem;
  box-shadow: var(--shadow);
  color: var(--text-main);
  cursor: pointer;
  display: inline-flex;
  font-family: var(--font-family);
  font-size: 0.85rem;
  font-weight: 700;
  gap: 0.45rem;
  left: 1.25rem;
  padding: 0.45rem 0.95rem;
  position: fixed;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  z-index: 9999;
}

.theme-toggle:hover {
  border-color: var(--primary);
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.3);
  transform: translateY(-2px);
}

.theme-toggle .theme-icon {
  font-size: 1rem;
}

p, blockquote, li {
  text-wrap: pretty;
}

a {
  color: var(--primary);
  text-decoration: none;
  transition: color 0.15s ease-in-out;
}

a:hover {
  color: var(--primary-hover);
  text-decoration: underline;
}

a img {
  border: none;
}

.clear {
  clear: both;
  height: 0;
  overflow: hidden;
}

#container {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  margin: 1.5rem auto 3rem;
  max-width: 1100px;
  padding: 2rem 2.5rem;
  width: 92%;
}

@media (max-width: 768px) {
  #container {
    border-radius: var(--radius-md);
    margin: 1rem auto;
    padding: 1.25rem 1rem;
    width: 98%;
  }
}

input[type='text'],
input[type='password'],
input[type='email'],
select,
textarea {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-main);
  font-family: inherit;
  font-size: 0.95rem;
  padding: 0.45rem 0.65rem;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

input[type='text']:focus,
input[type='password']:focus,
input[type='email']:focus,
select:focus,
textarea:focus {
  border-color: var(--primary);
  outline: 2px solid var(--primary);
  outline-offset: 1px;
}

input[type='submit'],
button {
  background-color: var(--primary);
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  color: #ffffff;
  cursor: pointer;
  font-family: inherit;
  font-size: 0.9rem;
  font-weight: 500;
  padding: 0.45rem 0.9rem;
  transition: background-color 0.15s ease, transform 0.05s ease;
}

input[type='submit']:hover,
button:hover {
  background-color: var(--primary-hover);
}

input[type='submit']:active,
button:active {
  transform: translateY(1px);
}

#flash_notice,
#flash_error,
#flash_alert,
#flash_riccardo {
  border-radius: var(--radius-md);
  border-style: solid;
  border-width: 1px;
  font-weight: 500;
  margin: 1rem 0;
  padding: 0.75rem 1.25rem;
}

#flash_notice {
  background-color: var(--success-bg);
  border-color: var(--success);
  color: var(--success);
}

#flash_error,
#flash_alert {
  background-color: var(--danger-bg);
  border-color: var(--danger);
  color: var(--danger);
}

#flash_riccardo {
  background-color: var(--warning-bg);
  border-color: var(--warning);
  color: var(--warning);
}

.fieldWithErrors {
  display: inline;
}

.error_messages {
  background-color: var(--danger-bg);
  border: 1px solid var(--danger);
  border-radius: var(--radius-md);
  color: var(--danger);
  font-size: 0.9rem;
  margin-bottom: 1.5rem;
  padding: 1rem;
  width: 100%;
}

.error_messages h2 {
  background-color: transparent;
  color: var(--danger);
  font-size: 1rem;
  font-weight: 600;
  margin: 0 0 0.5rem;
  padding: 0;
  text-align: left;
}

.error_messages p {
  margin: 0.5rem 0;
}

.error_messages ul {
  margin: 0.5rem 0 0.5rem 1.5rem;
  padding: 0;
}