/* ============================================================
   LinkaGoGo — Shared Design Tokens
   Brand blue: #003ED3 (from linkagogo.com)
   Shared across landing page and /app
   ============================================================ */

/* --- CSS Custom Properties --- */
:root {
  /* Brand palette */
  --color-primary: #003ED3;
  --color-primary-dark: #0A2350;
  --color-primary-light: #87CCFF;
  --color-primary-hover: #0032A8;

  /* Surfaces */
  --color-bg: #ffffff;
  --color-bg-alt: #f5f7fa;
  --color-bg-card: #ffffff;
  --color-bg-hero: #f0f5ff;

  /* Text */
  --color-text: #1a1a2e;
  --color-text-secondary: #4a5568;
  --color-text-muted: #718096;
  --color-text-inverse: #ffffff;

  /* Borders */
  --color-border: #e2e8f0;
  --color-border-light: #edf2f7;

  /* Feedback */
  --color-success: #22c55e;
  --color-warning: #f59e0b;
  --color-error: #ef4444;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;

  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SF Mono", "Fira Code", "Fira Mono", "Roboto Mono", monospace;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;
  --text-5xl: 3rem;

  /* Sizing */
  --container-max: 1200px;
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07);
  --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 50px rgba(0, 0, 0, 0.12);
}

/* --- Dark Mode --- */
[data-theme="dark"] {
  --color-primary: #4d8aff;
  --color-primary-dark: #87CCFF;
  --color-primary-light: #0A2350;
  --color-primary-hover: #6b9fff;

  --color-bg: #0f1219;
  --color-bg-alt: #181d28;
  --color-bg-card: #1e2433;
  --color-bg-hero: #141824;

  --color-text: #e8eaf0;
  --color-text-secondary: #a0aec0;
  --color-text-muted: #718096;
  --color-text-inverse: #0f1219;

  --color-border: #2d3748;
  --color-border-light: #252d3d;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.25);
  --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.3);
  --shadow-xl: 0 20px 50px rgba(0, 0, 0, 0.35);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --color-primary: #4d8aff;
    --color-primary-dark: #87CCFF;
    --color-primary-light: #0A2350;
    --color-primary-hover: #6b9fff;

    --color-bg: #0f1219;
    --color-bg-alt: #181d28;
    --color-bg-card: #1e2433;
    --color-bg-hero: #141824;

    --color-text: #e8eaf0;
    --color-text-secondary: #a0aec0;
    --color-text-muted: #718096;
    --color-text-inverse: #0f1219;

    --color-border: #2d3748;
    --color-border-light: #252d3d;

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.2);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.25);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.3);
    --shadow-xl: 0 20px 50px rgba(0, 0, 0, 0.35);
  }
}

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

html {
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--color-primary);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

ul[role="list"] {
  list-style: none;
}

/* --- Skip Link --- */
.skip-link {
  position: absolute;
  top: -100%;
  left: var(--space-md);
  z-index: 1000;
  padding: var(--space-sm) var(--space-md);
  background: var(--color-primary);
  color: var(--color-text-inverse);
  border-radius: var(--radius-sm);
  font-weight: 600;
}

.skip-link:focus {
  top: var(--space-md);
}

/* --- Visually Hidden --- */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  font-family: inherit;
  font-weight: 600;
  text-decoration: none;
  border: 2px solid transparent;
  border-radius: var(--radius-md);
  cursor: pointer;
  white-space: nowrap;
  line-height: 1;
}

@media (prefers-reduced-motion: no-preference) {
  .btn {
    transition: background-color 0.15s ease, border-color 0.15s ease, transform 0.1s ease;
  }
}

.btn:hover {
  text-decoration: none;
}

.btn:focus-visible {
  outline: 3px solid var(--color-primary);
  outline-offset: 2px;
}

.btn-sm {
  padding: var(--space-sm) var(--space-md);
  font-size: var(--text-sm);
}

.btn-lg {
  padding: var(--space-md) var(--space-xl);
  font-size: var(--text-lg);
}

.btn-primary {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
  border-color: var(--color-primary);
}

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

.btn-outline {
  background-color: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.btn-outline:hover {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
}

.btn-ghost {
  background-color: transparent;
  color: var(--color-text-secondary);
  border-color: var(--color-border);
}

.btn-ghost:hover {
  border-color: var(--color-text-secondary);
  color: var(--color-text);
}

.btn-block {
  display: block;
  width: 100%;
  text-align: center;
  padding: var(--space-md) var(--space-lg);
  font-size: var(--text-base);
}

.btn-danger {
  background-color: var(--color-error);
  color: #ffffff;
  border-color: var(--color-error);
}

.btn-danger:hover {
  background-color: #dc2626;
  border-color: #dc2626;
}

/* --- Focus visible for keyboard nav --- */
a:focus-visible,
button:focus-visible {
  outline: 3px solid var(--color-primary);
  outline-offset: 2px;
}

/* --- Theme toggle --- */
.theme-toggle {
  background: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  padding: var(--space-sm);
  min-width: 44px;
  min-height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-secondary);
  flex-shrink: 0;
}

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

.theme-toggle:focus-visible {
  outline: 3px solid var(--color-primary);
  outline-offset: 2px;
}

.theme-toggle-icon::after {
  content: "\2600"; /* sun */
  font-size: 1.25rem;
}

[data-theme="dark"] .theme-toggle-icon::after {
  content: "\1F319"; /* crescent moon */
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .theme-toggle-icon::after {
    content: "\1F319";
  }
}