/* ========================================
   GPA Calculator Website - Main Stylesheet
   Refreshed UI (Calculator.net inspired) + Responsive
   ======================================== */

/* === Variables === */ 
:root {
  --nav-bg: #0b3f6a;
  --nav-bg-2: #0a355a;
  --nav-text: #ffffff;

  --primary: #1e5aa8;
  --primary-dark: #174a8a;
  --link: #1e5aa8;

  --success: #2f9d57;
  --danger: #d9534f;

  --text: #1f2a37;
  --text-muted: #52606d;

  --bg: #ffffff;
  --bg-soft: #f5f7fb;
  --panel: #ffffff;

  --border: #d9dee7;
  --border-soft: #e8ecf3;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 6px 18px rgba(0, 0, 0, 0.10);

  --radius: 8px;
  --radius-lg: 12px;

  --container: 1100px;
  --transition: 160ms ease;
}

/* === Reset === */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  /* Prefer Helvetica like Calculator.net */
  font-family: Helvetica, Arial, sans-serif;
  font-weight: 400;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
}
img { max-width: 100%; height: auto; }
a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }

/* === Typography === */
h1 { font-size: clamp(1.75rem, 3vw, 2.25rem); margin: 0 0 .5rem; line-height: 1.25; font-weight: 600; }
h2 { font-size: clamp(1.25rem, 2.4vw, 1.6rem); margin: 2rem 0 1rem; font-weight: 600; }
h3 { font-size: 1.15rem; margin: 1.5rem 0 .75rem; font-weight: 600; }
p { margin: 0 0 1rem; color: #262626; }

/* === Container === */
.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 16px;
}

/* === Header (Calculator.net style) === */
header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--nav-bg);
  box-shadow: var(--shadow-sm);
}

.header-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 0px;
}

.logo {
  color: var(--nav-text);
  font-weight: 600;
  font-size: 1.25rem;
  letter-spacing: .2px;
  text-decoration: none;
  white-space: nowrap;
}
.logo:hover { text-decoration: none; opacity: .92; }

nav ul {
  display: flex;
  gap: 18px;
  list-style: none;
  margin: 0;
  padding: 0;
}

nav ul li a {
  color: rgba(255, 255, 255, .92);
  font-weight: 500;
  font-size: .95rem;
  padding: 8px 10px;
  border-radius: 6px;
  transition: background var(--transition), color var(--transition);
}

nav ul li a:hover {
  background: rgba(255, 255, 255, .12);
  color: #fff;
  text-decoration: none;
}

/* Mobile Menu Toggle */
.menu-toggle {
  display: none;
  flex-direction: column;
  cursor: pointer;
  gap: 5px;
  padding: 8px;
  border-radius: 8px;
  background: rgba(255, 255, 255, .08);
}
.menu-toggle span {
  width: 24px;
  height: 3px;
  background: #fff;
  border-radius: 2px;
}

/* === Main === */
main {
  padding: 22px 0 40px;
}

.breadcrumbs {
  font-size: .9rem;
  color: var(--text-muted);
  margin: 10px 0 8px;
}

/* === Page Layout (Sidebar + Content) === */
.page-layout {
  display: grid;
}

.sidebar {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--panel);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
  padding: 0 15px;
}

.sidebar .sidebar-title {
  background: #f0f3f9;
  border-bottom: 1px solid var(--border);
  padding: 10px 12px;
  font-weight: 600;
  color: #20314a;
}

.sidebar ul {
  list-style: none;
  margin: 0;
  padding: 8px 0;
}

.sidebar a {
  display: block;
  padding: 8px 12px;
  color: var(--primary);
  font-weight: 500;
}

/* Keep bold usage subtle */
strong { font-weight: 600; }

.sidebar a:hover {
  background: var(--bg-soft);
  text-decoration: none;
}

/* === Hero (more compact) === */
.hero {
  padding: 6px 0 16px;
}

.hero p {
  margin: 0;
  color: var(--text-muted);
  max-width: 900px;
}

/* === Ad Placeholders === */
.ad-container {
  background: var(--bg-soft);
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: 18px;
  text-align: center;
  color: var(--text-muted);
  margin: 18px 0;
  min-height: 210px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: .9rem;
  font-weight: 600;
}
.ad-container::before { content: 'Ad Space'; }

/* === Calculator Container === */
.calculator-container {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  padding: 18px;
  margin: 10px 0 22px;
}

.calculator-header {
  background: var(--primary);
  border-radius: 10px;
  padding: 14px 16px;
  color: #fff;
  margin-bottom: 14px;
}

.calculator-header h2 {
  margin: 0;
  color: #fff;
  font-size: 1.25rem;
}

.calculator-header p {
  margin: 6px 0 0;
  color: rgba(255, 255, 255, .92);
}

.subjects-container { margin-bottom: 14px; }

.subject-row {
  display: grid;
  grid-template-columns: 2fr 1fr 1.1fr auto;
  gap: 10px;
  padding: 12px;
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  background: #fbfcfe;
  margin-bottom: 10px;
}

.form-group { display: flex; flex-direction: column; }
.form-group label { font-size: .85rem; font-weight: 600; color: #31465e; margin-bottom: 6px; }

.form-group input,
.form-group select {
  padding: 10px 10px;
  border: 1px solid var(--border);
  border-radius: 7px;
  font-size: 1rem;
  background: #fff;
  transition: border var(--transition), box-shadow var(--transition);
}

.form-group input:focus,
.form-group select:focus {
  outline: none;
  border-color: rgba(30, 90, 168, .65);
  box-shadow: 0 0 0 3px rgba(30, 90, 168, .14);
}

.form-group input[type="number"]::-webkit-outer-spin-button,
.form-group input[type="number"]::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.btn {
  border: none;
  cursor: pointer;
  border-radius: 8px;
  font-weight: 600;
  padding: 11px 14px;
  transition: transform var(--transition), background var(--transition), box-shadow var(--transition);
}

.btn-add-subject {
  width: 100%;
  background: var(--success);
  color: #fff;
  margin: 6px 0 12px;
}
.btn-add-subject:hover { background: #27874a; transform: translateY(-1px); box-shadow: var(--shadow-sm); }

.btn-calculate {
  width: 100%;
  background: var(--primary);
  color: #fff;
  padding: 12px 16px;
  font-size: 1.05rem;
}
.btn-calculate:hover { background: var(--primary-dark); transform: translateY(-1px); box-shadow: var(--shadow-sm); }

.btn-remove {
  background: var(--danger);
  color: #fff;
  padding: 10px 12px;
  min-width: 86px;
}
.btn-remove:hover { background: #c64642; transform: translateY(-1px); box-shadow: var(--shadow-sm); }

.calculator-actions {
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px solid var(--border);
}

.gpa-result {
  display: none;
  margin-top: 14px;
  border-radius: var(--radius-lg);
  border: 1px solid rgba(30, 90, 168, .25);
  background: #f1f6ff;
  padding: 18px;
  text-align: center;
}
.gpa-result.show { display: block; }
.gpa-result h3 { margin: 0 0 8px; color: #1c4f94; }
.gpa-value { font-size: clamp(2.2rem, 6vw, 3.2rem); font-weight: 900; color: #0f2f5b; margin: 6px 0 8px; }
.gpa-message { margin: 0; color: #243b53; }

/* === Content Sections === */
.content-section {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--panel);
  box-shadow: var(--shadow-sm);
  padding: 18px;
  margin-bottom: 18px;
}

.content-section h2 { margin-top: 0; color: #143a73; }

.content-section ul,
.content-section ol {
  margin: 0 0 1rem 1.25rem;
}

.content-section table {
  width: 100%;
  border-collapse: collapse;
  margin: 14px 0;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.content-section table th,
.content-section table td {
  padding: 10px;
  border-bottom: 1px solid var(--border-soft);
  text-align: left;
}

.content-section table th {
  background: var(--primary);
  color: #fff;
}

/* === Contact form container === */
.form-container {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--panel);
  box-shadow: var(--shadow-md);
  padding: 18px;
  max-width: 680px;
}

.form-container .form-group { margin-bottom: 12px; }

.btn-submit {
  width: 100%;
  background: var(--primary);
  color: #fff;
  padding: 12px 16px;
  font-size: 1.05rem;
}
.btn-submit:hover { background: var(--primary-dark); transform: translateY(-1px); box-shadow: var(--shadow-sm); }

/* === Footer === */
footer {
  margin-top: 30px;
  background: #eef2f7;
  border-top: 1px solid var(--border);
  color: #1f2a37;
}

.footer-content {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 18px;
  padding: 20px 0;
}

.footer-section h3 {
  margin: 0 0 10px;
  color: #143a73;
}

.footer-section p,
.footer-section a { color: #243b53; }

.footer-section ul { list-style: none; padding: 0; margin: 0; }
.footer-section li { margin-bottom: 6px; }

.footer-bottom {
  text-align: center;
  padding: 12px 0 18px;
  border-top: 1px solid var(--border);
  color: var(--text-muted);
}

/* === Responsive === */
@media (max-width: 980px) {
  .page-layout { grid-template-columns: 1fr; }
  .sidebar { order: 2; }
}

@media (max-width: 768px) {
  .menu-toggle { display: flex; }

  nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    background: var(--nav-bg-2);
    display: none;
    border-top: 1px solid rgba(255, 255, 255, .15);
  }

  nav.active { display: block; }

  nav ul {
    flex-direction: column;
    gap: 0;
    padding: 10px 10px 14px;
  }

  nav ul li a {
    display: block;
    padding: 10px 10px;
  }

  .subject-row {
    grid-template-columns: 1fr;
  }

  .btn-remove { width: 100%; }

  .footer-content { grid-template-columns: 1fr; }
}

@media (max-width: 420px) {
  .header-content { padding: 10px 12px; }
  main { padding-top: 16px; }
}

/* === Utility === */
.text-center { text-align: center; }
.hidden { display: none; }
.semi { font-weight: 600; }

.breadcrumbs {
    text-transform: capitalize;
}

.header-content img {
    filter: brightness(0) invert(0.9);
    width: 200px;
}