/* ========================================================================== 
   Variables
   ========================================================================== */

:root {
  /* Colors */
  --color-background: #05070b;
  --color-surface: #0c1018;
  --color-surface-soft: #151b26;
  --color-text: #f7fafc;
  --color-text-muted: #a0aec0;
  --color-border-subtle: #2d3748;

  /* Vibrant palette inspired by Flow Free pipes */
  --color-primary: #00bcd4;  /* Cyan */
  --color-primary-soft: rgba(0, 188, 212, 0.1);
  --color-success: #22c55e;  /* Green */
  --color-warning: #facc15;  /* Yellow */
  --color-danger: #ef4444;   /* Red */
  --color-accent-orange: #fb923c;
  --color-accent-blue: #3b82f6;
  --color-accent-purple: #a855f7;

  /* Neutral grays */
  --gray-50: #f9fafb;
  --gray-100: #f4f4f5;
  --gray-200: #e5e7eb;
  --gray-300: #d4d4d8;
  --gray-400: #a1a1aa;
  --gray-500: #71717a;
  --gray-600: #52525b;
  --gray-700: #3f3f46;
  --gray-800: #27272f;
  --gray-900: #18181b;

  /* Typography */
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;

  --font-size-xs: 0.75rem;   /* 12px */
  --font-size-sm: 0.875rem;  /* 14px */
  --font-size-base: 1rem;    /* 16px */
  --font-size-lg: 1.125rem;  /* 18px */
  --font-size-xl: 1.25rem;   /* 20px */
  --font-size-2xl: 1.5rem;   /* 24px */
  --font-size-3xl: 1.875rem; /* 30px */
  --font-size-4xl: 2.25rem;  /* 36px */

  --line-height-tight: 1.2;
  --line-height-normal: 1.6;
  --line-height-relaxed: 1.8;

  /* Spacing scale (px) */
  --space-0: 0;
  --space-1: 0.25rem;  /* 4px */
  --space-2: 0.5rem;   /* 8px */
  --space-3: 0.75rem;  /* 12px */
  --space-4: 1rem;     /* 16px */
  --space-5: 1.25rem;  /* 20px */
  --space-6: 1.5rem;   /* 24px */
  --space-8: 2rem;     /* 32px */
  --space-10: 2.5rem;  /* 40px */
  --space-12: 3rem;    /* 48px */
  --space-16: 4rem;    /* 64px */
  --space-20: 5rem;    /* 80px */
  --space-24: 6rem;    /* 96px */

  /* Radius */
  --radius-xs: 2px;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 16px;
  --radius-pill: 999px;

  /* Shadows (subtle, to keep focus/relaxation feel) */
  --shadow-xs: 0 1px 2px rgba(15, 23, 42, 0.35);
  --shadow-sm: 0 4px 10px rgba(15, 23, 42, 0.45);
  --shadow-md: 0 12px 30px rgba(15, 23, 42, 0.55);

  /* Transitions */
  --transition-fast: 120ms ease-out;
  --transition-normal: 200ms ease-out;
  --transition-slow: 320ms ease-out;

  /* Layout */
  --container-max-width: 1120px;
}

@media (min-width: 768px) {
  :root {
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.375rem;
    --font-size-2xl: 1.75rem;
    --font-size-3xl: 2.125rem;
    --font-size-4xl: 2.5rem;
  }
}

/* ========================================================================== 
   Reset / Normalize
   ========================================================================== */

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

html,
body {
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  text-size-adjust: 100%;
}

body {
  min-height: 100vh;
}

img,
svg,
video,
canvas,
audio,
iframe {
  max-width: 100%;
  height: auto;
}

img,
svg,
video {
  display: block;
}

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

button {
  border: none;
  background: none;
  padding: 0;
  cursor: pointer;
}

ul,
ol {
  margin: 0;
  padding: 0;
}

h1,
h2,
h3,
h4,
h5,
h6,
p,
figure,
blockquote,
dl,
dd {
  margin: 0;
}

fieldset {
  margin: 0;
  padding: 0;
  border: 0;
}

/* Respect reduced motion preference */

@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ========================================================================== 
   Base Styles
   ========================================================================== */

body {
  font-family: var(--font-sans);
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  background-color: var(--color-background);
  color: var(--color-text);
  -webkit-font-smoothing: antialiased;
}

::selection {
  background: rgba(0, 188, 212, 0.25);
  color: #f9fafb;
}

/* Headings: clean hierarchy, suited for clear guides/FAQs */

h1,
h2,
h3,
h4,
h5,
h6 {
  font-weight: 700;
  line-height: var(--line-height-tight);
  letter-spacing: 0.02em;
  color: var(--color-text);
}

h1 {
  font-size: var(--font-size-4xl);
  margin-bottom: var(--space-4);
}

h2 {
  font-size: var(--font-size-3xl);
  margin-top: var(--space-8);
  margin-bottom: var(--space-2);
}

h3 {
  font-size: var(--font-size-2xl);
  margin-top: var(--space-6);
  margin-bottom: var(--space-2);
}

h4 {
  font-size: var(--font-size-xl);
  margin-top: var(--space-4);
  margin-bottom: var(--space-2);
}

h5 {
  font-size: var(--font-size-lg);
  margin-top: var(--space-3);
  margin-bottom: var(--space-1);
}

h6 {
  font-size: var(--font-size-sm);
  margin-top: var(--space-3);
  margin-bottom: var(--space-1);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
}

p {
  margin-top: 0;
  margin-bottom: var(--space-3);
  color: var(--color-text);
  }

p + p {
  margin-top: var(--space-2);
}

small {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

strong {
  font-weight: 600;
}

code,
pre {
  font-family: var(--font-mono);
}

pre {
  padding: var(--space-3);
  border-radius: var(--radius-md);
  background: rgba(15, 23, 42, 0.9);
  overflow-x: auto;
}

/* Links: minimalist but clearly interactive */

a {
  color: var(--color-primary);
  text-decoration: none;
  position: relative;
  transition: color var(--transition-normal),
              opacity var(--transition-fast);
}

a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -0.1em;
  width: 0;
  height: 2px;
  border-radius: var(--radius-pill);
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent-purple));
  transition: width var(--transition-normal);
}

a:hover::after,
a:focus-visible::after {
  width: 100%;
}

a:hover {
  color: #5ee7ff;
}

a:active {
  opacity: 0.85;
}

/* Lists for organized content (guides, FAQs) */

ul,
ol {
  padding-left: var(--space-5);
  margin-bottom: var(--space-3);
}

li + li {
  margin-top: var(--space-1);
}

hr {
  border: none;
  border-top: 1px solid var(--color-border-subtle);
  margin: var(--space-6) 0;
}

/* ========================================================================== 
   Accessibility & Focus
   ========================================================================== */

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

:focus {
  outline: none;
}

/* Screen reader only */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.sr-only-focusable:active,
.sr-only-focusable:focus {
  position: static;
  width: auto;
  height: auto;
  margin: 0;
  overflow: visible;
  clip: auto;
  white-space: normal;
}

/* ========================================================================== 
   Utilities
   ========================================================================== */

/* Layout containers */

.container {
  width: 100%;
  max-width: var(--container-max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--space-4);
  padding-right: var(--space-4);
}

.section {
  padding-top: var(--space-12);
  padding-bottom: var(--space-12);
}

.section--compact {
  padding-top: var(--space-8);
  padding-bottom: var(--space-8);
}

/* Flex helpers */

.flex {
  display: flex;
}

.inline-flex {
  display: inline-flex;
}

.flex-col {
  flex-direction: column;
}

.flex-row {
  flex-direction: row;
}

.flex-center {
  display: flex;
  align-items: center;
  justify-content: center;
}

.items-center {
  align-items: center;
}

.items-start {
  align-items: flex-start;
}

.items-end {
  align-items: flex-end;
}

.justify-center {
  justify-content: center;
}

.justify-between {
  justify-content: space-between;
}

.gap-2 {
  gap: var(--space-2);
}

.gap-3 {
  gap: var(--space-3);
}

.gap-4 {
  gap: var(--space-4);
}

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

/* Grid helpers (for boards/diagrams or FAQ layouts) */

.grid {
  display: grid;
}

.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.grid-auto-fit {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

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

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

@media (max-width: 767px) {
  .grid-2,
  .grid-3 {
    grid-template-columns: minmax(0, 1fr);
  }
}

/* Spacing utilities (for quick layout tweaks) */

.mt-0 { margin-top: 0; }
.mt-2 { margin-top: var(--space-2); }
.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.mt-8 { margin-top: var(--space-8); }

.mb-0 { margin-bottom: 0; }
.mb-2 { margin-bottom: var(--space-2); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }
.mb-8 { margin-bottom: var(--space-8); }

.pt-4 { padding-top: var(--space-4); }
.pt-6 { padding-top: var(--space-6); }
.pt-8 { padding-top: var(--space-8); }

.pb-4 { padding-bottom: var(--space-4); }
.pb-6 { padding-bottom: var(--space-6); }
.pb-8 { padding-bottom: var(--space-8); }

.text-center { text-align: center; }
.text-right { text-align: right; }

.text-muted { color: var(--color-text-muted); }


/* Focused board-like blocks (for diagrams/puzzle grids) */

.board-frame {
  border-radius: var(--radius-lg);
  background: radial-gradient(circle at top left, rgba(59, 130, 246, 0.15), transparent),
              radial-gradient(circle at bottom right, rgba(244, 63, 94, 0.15), transparent),
              var(--color-surface);
  padding: var(--space-4);
  box-shadow: var(--shadow-sm);
}

/* ========================================================================== 
   Components
   ========================================================================== */

/* Buttons: primary CTAs for guides, downloads, joining community */

.btn,
button.btn,
input[type="button"].btn,
input[type="submit"].btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: 0.55rem 1.4rem;
  border-radius: var(--radius-pill);
  font-weight: 600;
  font-size: var(--font-size-sm);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  text-decoration: none;
  border: 1px solid transparent;
  color: #0b1120;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent-purple));
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-fast),
              box-shadow var(--transition-fast),
              filter var(--transition-fast),
              background var(--transition-normal);
}

.btn:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
  filter: brightness(1.05);
}

.btn:active {
  transform: translateY(0);
  box-shadow: var(--shadow-xs);
  filter: brightness(0.98);
}

.btn:disabled,
.btn[aria-disabled="true"] {
  cursor: not-allowed;
  opacity: 0.6;
  box-shadow: none;
}

.btn--outline {
  background: transparent;
  color: var(--color-primary);
  border-color: rgba(148, 163, 184, 0.6);
  box-shadow: none;
}

.btn--outline:hover {
  background: var(--color-primary-soft);
  box-shadow: var(--shadow-xs);
}

.btn--ghost {
  background: transparent;
  color: var(--color-text);
  box-shadow: none;
}

.btn--ghost:hover {
  background: rgba(15, 23, 42, 0.7);
}

/* Inputs / form controls for search, newsletter, contact, FAQ submit */

input[type="text"],
input[type="email"],
input[type="search"],
input[type="password"],
input[type="url"],
textarea,
select {
  width: 100%;
  padding: 0.6rem 0.8rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border-subtle);
  background-color: var(--color-surface-soft);
  color: var(--color-text);
  font-size: var(--font-size-sm);
  line-height: 1.4;
  transition: border-color var(--transition-fast),
              box-shadow var(--transition-fast),
              background-color var(--transition-fast);
}

input::placeholder,
textarea::placeholder {
  color: var(--color-text-muted);
}

input:focus-visible,
textarea:focus-visible,
select:focus-visible {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 1px rgba(0, 188, 212, 0.5);
  background-color: #050814;
}

textarea {
  min-height: 120px;
  resize: vertical;
}

label {
  display: inline-block;
  margin-bottom: var(--space-1);
  font-size: var(--font-size-sm);
  font-weight: 500;
}

.field-group {
  margin-bottom: var(--space-4);
}

.field-error {
  margin-top: var(--space-1);
  font-size: var(--font-size-xs);
  color: var(--color-danger);
}

/* Card: for content blocks, guides, FAQ items, community highlights */

.card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-4);
  box-shadow: var(--shadow-sm);
  border: 1px solid rgba(148, 163, 184, 0.2);
}

.card--soft {
  background: linear-gradient(145deg, rgba(15, 23, 42, 0.96), rgba(15, 23, 42, 0.98));
}

.card-header {
  margin-bottom: var(--space-3);
}

.card-title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin-bottom: var(--space-1);
}

.card-meta {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

.card-body {
  font-size: var(--font-size-sm);
  color: var(--color-text);
}

/* Tag / pill (e.g., difficulty levels, categories) */

.tag {
  display: inline-flex;
  align-items: center;
  padding: 0.1rem 0.6rem;
  border-radius: var(--radius-pill);
  font-size: var(--font-size-xs);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  border: 1px solid rgba(148, 163, 184, 0.45);
  color: var(--color-text-muted);
}

.tag--easy {
  border-color: rgba(34, 197, 94, 0.7);
  color: #bbf7d0;
}

.tag--medium {
  border-color: rgba(250, 204, 21, 0.7);
  color: #fef9c3;
}

.tag--hard {
  border-color: rgba(239, 68, 68, 0.7);
  color: #fecaca;
}

/* Info banners (community notes, updates) */

.banner {
  border-radius: var(--radius-lg);
  padding: var(--space-3) var(--space-4);
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  border: 1px solid rgba(148, 163, 184, 0.35);
  background: linear-gradient(135deg, rgba(15, 23, 42, 0.9), rgba(15, 23, 42, 0.96));
}

.banner--info {
  border-color: rgba(0, 188, 212, 0.7);
}

.banner--success {
  border-color: rgba(34, 197, 94, 0.7);
}

.banner--warning {
  border-color: rgba(250, 204, 21, 0.7);
}

.banner--danger {
  border-color: rgba(239, 68, 68, 0.7);
}

.banner-icon {
  font-size: 1.3em;
}

.banner-body {
  flex: 1;
  font-size: var(--font-size-sm);
}

/* Simple nav shell hint (for top navigation) */

.navbar {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(14px);
  background: linear-gradient(180deg, rgba(15, 23, 42, 0.92), rgba(15, 23, 42, 0.82));
  border-bottom: 1px solid rgba(148, 163, 184, 0.25);
}

.navbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-3) var(--space-4);
}

.nav-links {
  display: flex;
  gap: var(--space-4);
  align-items: center;
}

.nav-link {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.nav-link:hover,
.nav-link[aria-current="page"] {
  color: var(--color-text);
}

/* Footer */

.footer {
  border-top: 1px solid rgba(148, 163, 184, 0.25);
  padding: var(--space-6) 0;
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}

/* ========================================================================== 
   End of base.css
   ========================================================================== */