:root{
  /* Palette (light blues) */
  --bg: #f6fbff;           /* page background - very light blue */
  --surface: #ffffff;      /* cards, panels */
  --muted: #e6f2fb;        /* subtle surface tint */
  --text: #0b324d;         /* main body text (dark blue) */
  --heading: #073049;      /* headings - slightly darker */
  --accent: #2f9bff;       /* primary accent / links (mid blue) */
  --accent-strong: #1977d6;/* stronger accent for buttons etc */
  --accent-soft: #d7efff;  /* gentle accent background */
  --border: #d7e9f6;       /* soft border color */
  --muted-text: #40637a;   /* secondary text */
  --code-bg: #eaf7ff;      /* code block background */
  --success: #2ea44f;
  --danger: #d64545;

  --radius: 10px;
  --radius-sm: 6px;
  --gap: 1rem;
  --max-width: 85ch; /* good measure for readable text */
  --text-size: 16px;
  --line-height: 1.65;
  --shadow: 0 6px 18px rgba(11,50,77,0.06);
  --shadow-sm: 0 3px 8px rgba(11,50,77,0.04);
}

/* Global reset + typographic rhythm */
* { box-sizing: border-box; }
html,body { height: 100%; }
body{
  background: linear-gradient(180deg, var(--bg), #fbfeff);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial;
  font-size: var(--text-size);
  line-height: var(--line-height);
  margin: 0;
  padding: 2rem;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Content wrapper for comfortable reading */
.container{
  max-width: calc(var(--max-width) + 4rem);
  margin: 0 auto;
  padding: 2rem;
}

/* Article / readable text block */
.article {
  max-width: var(--max-width);
  margin: 0 auto;
  background: linear-gradient(180deg, rgba(255,255,255,0.6), rgba(255,255,255,0.9));
  padding: 2rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
}

/* Headings */
h1,h2,h3,h4{
  color: var(--heading);
  margin: 0 0 0.5rem 0;
  line-height: 1.15;
  letter-spacing: -0.01em;
}
h1{ font-size: 1.8rem; margin-bottom: 0.6rem; }
h2{ font-size: 1.35rem; margin-top: 1.1rem; }
h3{ font-size: 1.15rem; }

/* Paragraphs & lists */
p { margin: 0 0 1rem 0; color: var(--muted-text); }
ul,ol { margin: 0 0 1rem 1.25rem; color: var(--muted-text); }

/* Links */
a{
  color: var(--accent);
  text-decoration: none;
  border-bottom: 2px solid rgba(47,155,255,0.12);
  padding-bottom: 1px;
}
a:hover, a:focus { color: var(--accent-strong); outline: none; }

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.6ch;
  background: linear-gradient(180deg,var(--accent),var(--accent-strong));
  color: white;
  border: none;
  padding: 0.55rem 0.9rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  box-shadow: var(--shadow-sm);
  cursor: pointer;
  transition: transform 160ms ease, box-shadow 160ms ease;
}
.btn:hover{ transform: translateY(-2px); box-shadow: 0 8px 22px rgba(25,119,214,0.12); }
.btn:active{ transform: translateY(0); }
.btn.ghost{
  background: transparent;
  color: var(--accent-strong);
  border: 1px solid var(--border);
  box-shadow: none;
}

/* Cards */
.card{
  background: var(--surface);
  border-radius: var(--radius);
  padding: 1rem;
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
}

/* Form elements */
input[type="text"], textarea, select {
  width: 100%;
  padding: 0.65rem 0.75rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: linear-gradient(180deg,#ffffff,var(--muted));
  font: inherit;
  color: var(--text);
  outline: none;
  transition: box-shadow 120ms ease, border-color 120ms ease;
}
input[type="text"]:focus, textarea:focus, select:focus{
  border-color: var(--accent-strong);
  box-shadow: 0 6px 20px rgba(31,119,214,0.06);
}

/* Table */
.table {
  width: 100%;
  border-collapse: collapse;
  background: var(--surface);
  border-radius: var(--radius);
  overflow: hidden;
}
.table th, .table td {
  padding: 0.6rem 0.8rem;
  border-bottom: 1px solid var(--muted);
  color: var(--muted-text);
  text-align: left;
}
.table thead th {
  background: linear-gradient(180deg,var(--muted),white);
  color: var(--heading);
  font-weight: 700;
}

/* Code blocks and inline code */
pre, code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, "Roboto Mono", monospace;
  font-size: 0.95rem;
}
code {
  background: var(--code-bg);
  padding: 0.15rem 0.35rem;
  border-radius: 6px;
  color: var(--heading);
}
pre {
  background: linear-gradient(180deg,var(--code-bg),#f4fbff);
  padding: 1rem;
  border-radius: var(--radius-sm);
  overflow: auto;
  border: 1px solid var(--border);
  color: var(--text);
}

/* Small utilities */
.kicker{ font-size: 0.85rem; color: var(--accent-strong); font-weight: 700; letter-spacing: 0.06em; }
.lead{ font-size: 1.05rem; color: var(--muted-text); margin-bottom: 1rem; }

/* Focus for keyboard users */
:focus {
  outline: none;
}
:focus-visible {
  box-shadow: 0 0 0 4px rgba(47,155,255,0.14), 0 2px 10px rgba(11,50,77,0.06);
  border-radius: 8px;
}

/* Accessibility helpers */
@media (prefers-reduced-motion: reduce) {
  .btn, a, input, textarea { transition: none !important; }
}

/* Optional — subtle page header */
.page-header {
  display:flex;
  align-items:center;
  gap: 1rem;
  margin-bottom: 1.25rem;
}
.brand {
  width:56px;
  height:56px;
  border-radius: 10px;
  background: linear-gradient(180deg,var(--accent-soft),var(--accent));
  display:flex;
  align-items:center;
  justify-content:center;
  color: var(--accent-strong);
  font-weight:700;
  box-shadow: var(--shadow-sm);
}