/* ==========================================================================
   KTU CGPA Calculator — Stylesheet
   ========================================================================== */

/* --- CSS Custom Properties (EntriVerse design tokens) --- */
:root {
  /* Reference tokens: colors */
  --color-primary: #0061B5;        /* blue-700 */
  --color-primary-dark: #004B8C;   /* blue-800 / blue-hover */
  --color-primary-light: #0089FF;  /* blue-500 / entri-blue */
  --color-primary-container: #E6F3FF; /* blue-50 / blue-container */
  --color-success: #00805C;        /* green-500 / entri-green */
  --color-success-dark: #004633;   /* green-800 / on-green-container */
  --color-success-container: #E6F2EF; /* green-50 / green-container */
  --color-success-container-dark: #B0D8CC; /* green-100 */
  --color-bg: #F0F0F0;             /* grey-30 / background-grey */
  --color-surface: #FFFFFF;        /* pure-white */
  --color-text: #212121;           /* grey-1000 / primary-text */
  --color-text-muted: #616161;     /* grey-90 / subtext */
  --color-text-placeholder: #949494; /* grey-60 / placeholder-text */
  --color-border: #CFCFCF;         /* grey-40 */
  --color-error: #F65A5B;          /* red-500 / error-color */
  --color-error-bg: #FEEFEF;       /* red-50 / error-container */
  --color-error-border: #FBB3B4;   /* red-200 */

  /* Reference tokens: shape (entriverse `rounded` scale) */
  --radius: 8px;       /* rounded.m — cards */
  --radius-sm: 8px;     /* rounded.m — containers/rows */
  --radius-xs: 4px;     /* rounded.s — inputs/chips/tags */
  --radius-full: 200px; /* rounded.full — buttons */

  /* Reference tokens: elevation (entriverse levels 1/2/4) */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.10), 0 2px 1px rgba(0, 0, 0, 0.06), 0 1px 1px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 1px 5px rgba(0, 0, 0, 0.10), 0 3px 1px rgba(0, 0, 0, 0.06), 0 2px 2px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 2px 4px rgba(0, 0, 0, 0.10), 0 1px 10px rgba(0, 0, 0, 0.06), 0 4px 5px rgba(0, 0, 0, 0.08);
  --shadow-primary: 0 8px 24px rgba(0, 97, 181, 0.25);

  --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

  --container-max: 1100px;
  --header-height: 0px;
}

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

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

body {
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

img,
svg {
  display: block;
  max-width: 100%;
}

a {
  color: inherit;
  text-decoration: none;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

input {
  font-family: inherit;
}

/* --- Layout --- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: 1.25rem;
}

.section {
  padding-block: 4rem;
}

.section--alt {
  background-color: var(--color-surface);
}

.section__header {
  text-align: center;
  margin-bottom: 2.5rem;
}

.section__title {
  font-size: clamp(1.25rem, 4vw, 1.5rem);
  font-weight: 700;
  color: var(--color-text);
  letter-spacing: 0.25px;
  margin-bottom: 0.5rem;
}

.section__desc {
  font-size: 1rem;
  color: var(--color-text-muted);
  line-height: 1.5;
  max-width: 560px;
  margin-inline: auto;
}

/* --- Card --- */
.card {
  background: var(--color-surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--color-border);
  transition: box-shadow var(--transition), transform var(--transition);
}

.card:hover {
  box-shadow: var(--shadow-lg);
}

/* --- Buttons (entriverse button-default: Inter Bold 14px, 0.5px letter-spacing, full pill radius) --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  font-size: 0.875rem;
  font-weight: 700;
  letter-spacing: 0.5px;
  border-radius: var(--radius-full);
  transition: background-color var(--transition), color var(--transition),
    box-shadow var(--transition), transform var(--transition), border-color var(--transition);
  white-space: nowrap;
}

.btn:active {
  transform: scale(0.97);
}

.btn--primary {
  background-color: var(--color-primary);
  color: #fff;
  box-shadow: var(--shadow-primary);
}

.btn--primary:hover {
  background-color: var(--color-primary-dark);
  box-shadow: 0 10px 28px rgba(0, 97, 181, 0.35);
}

.btn--outline {
  background-color: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}

.btn--outline:hover {
  background-color: rgba(0, 97, 181, 0.06);
}

.btn--ghost {
  background-color: transparent;
  color: var(--color-text-muted);
  border: 2px solid var(--color-border);
}

.btn--ghost:hover {
  background-color: var(--color-bg);
  color: var(--color-text);
  border-color: var(--color-text-placeholder);
}

.btn--lg {
  padding: 1rem 2rem;
  font-size: 1rem;
}

.btn--block {
  width: 100%;
}

.btn--danger {
  color: var(--color-error);
  border: 2px solid transparent;
  padding: 0.5rem;
  background: transparent;
}

.btn--danger:hover {
  background-color: var(--color-error-bg);
  border-color: var(--color-error-border);
}

.btn--icon {
  padding: 0.5rem;
  min-width: 2.5rem;
  min-height: 2.5rem;
}

/* ==========================================================================
   Site Navigation
   ========================================================================== */
.site-nav {
  position: relative;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
}

.site-nav__inner {
  position: relative;
  z-index: 210;
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--container-max);
  margin-inline: auto;
  padding: 0.9rem 1.25rem;
  background: var(--color-surface);
}

.site-nav__logo {
  display: flex;
  align-items: center;
  line-height: 0;
}

.site-nav__trigger {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.5rem 0.9rem;
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--color-text);
  border-radius: var(--radius-xs);
  transition: background-color var(--transition), color var(--transition);
}

.site-nav__trigger:hover {
  background: var(--color-bg);
}

.site-nav__trigger[aria-expanded="true"] {
  background: var(--color-bg);
  color: var(--color-primary);
}

.site-nav__chevron {
  transition: transform var(--transition);
}

.site-nav__trigger[aria-expanded="true"] .site-nav__chevron {
  transform: rotate(180deg);
}

/* --- Mega Menu --- */
.mega-menu {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  z-index: 200;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-lg);
  animation: megaMenuReveal 0.2s ease;
}

@keyframes megaMenuReveal {
  from {
    opacity: 0;
    transform: translateY(-6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.mega-menu__inner {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 2rem;
  max-width: var(--container-max);
  margin-inline: auto;
  padding: 2rem 1.25rem 2.25rem;
}

.mega-menu__column {
  display: flex;
  flex-direction: column;
  gap: 1.75rem;
  min-width: 0;
}

.mega-menu__heading {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 0.75rem;
}

.mega-menu__list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.mega-menu__link {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.875rem;
  color: var(--color-text);
  transition: color var(--transition);
}

.mega-menu__link:hover {
  color: var(--color-primary);
  text-decoration: underline;
}

.mega-menu__badge {
  font-size: 0.8em;
}

.mega-menu__backdrop {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  height: 100vh;
  z-index: 150;
  background: rgba(15, 23, 42, 0.25);
}

/* ==========================================================================
   Hero Section
   ========================================================================== */
.hero {
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 50%, var(--color-primary-light) 100%);
  color: #fff;
  padding-block: 5rem 6rem;
  text-align: center;
}

.hero__decoration {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 20% 80%, rgba(255, 255, 255, 0.08) 0%, transparent 50%),
    radial-gradient(circle at 80% 20%, rgba(255, 255, 255, 0.12) 0%, transparent 40%);
  pointer-events: none;
}

.hero__inner {
  position: relative;
  z-index: 1;
}

.hero__badge {
  display: inline-block;
  background: rgba(255, 255, 255, 0.15);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(255, 255, 255, 0.25);
  padding: 0.4rem 1rem;
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.25px;
  margin-bottom: 1.5rem;
}

.hero__title {
  font-size: clamp(2rem, 6vw, 3rem);
  font-weight: 700;
  letter-spacing: -1.5px;
  line-height: 1.2;
  margin-bottom: 1rem;
}

.hero__subtitle {
  font-size: 1rem;
  opacity: 0.9;
  max-width: 620px;
  margin-inline: auto;
  margin-bottom: 2rem;
  line-height: 1.5;
}

.hero__cta {
  background-color: #fff;
  color: var(--color-primary);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
}

.hero__cta:hover {
  background-color: var(--color-primary-container);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.2);
  transform: translateY(-2px);
}

.hero__cta svg {
  animation: bounce 2s infinite;
}

@keyframes bounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(4px); }
}

/* ==========================================================================
   Calculator Section
   ========================================================================== */
.calculator-card {
  padding: 2rem;
}

/* --- Mode / Scheme Toggle --- */
.toggle-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}

.toggle-row__hint {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  margin-bottom: 1.5rem;
}

.mode-toggle {
  display: inline-flex;
  padding: 0.25rem;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
}

.mode-toggle__btn {
  padding: 0.6rem 1.1rem;
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--color-text-muted);
  border-radius: var(--radius-xs);
  transition: background-color var(--transition), color var(--transition), box-shadow var(--transition);
}

.mode-toggle__btn.is-active {
  background: var(--color-surface);
  color: var(--color-primary);
  box-shadow: var(--shadow-sm);
}

.mode-toggle__btn:not(.is-active):hover {
  color: var(--color-text);
}

/* --- Branch Syllabus Loader --- */
.branch-loader {
  padding: 1rem 1.25rem;
  background: rgba(0, 97, 181, 0.05);
  border: 1px dashed rgba(0, 97, 181, 0.3);
  border-radius: var(--radius-sm);
  margin-bottom: 1.5rem;
}

.branch-loader label {
  display: block;
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--color-text);
  margin-bottom: 0.5rem;
}

.branch-loader select {
  width: 100%;
  max-width: 420px;
  padding: 0.65rem 0.9rem;
  font-size: 0.875rem;
  border: 2px solid var(--color-border);
  border-radius: var(--radius-xs);
  background: var(--color-surface);
  color: var(--color-text);
}

.branch-loader select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(0, 97, 181, 0.15);
}

.branch-loader__hint {
  margin-top: 0.5rem;
  font-size: 0.75rem;
  color: var(--color-text-muted);
  line-height: 1.5;
}

.semester-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.semester-row {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr auto;
  gap: 1rem;
  align-items: start;
  padding: 1.25rem;
  background: var(--color-bg);
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
  transition: border-color var(--transition), box-shadow var(--transition);
  animation: fadeSlideIn 0.3s ease;
}

.semester-row:hover {
  border-color: var(--color-text-placeholder);
}

.semester-row--error {
  border-color: var(--color-error-border);
  background: var(--color-error-bg);
}

@keyframes fadeSlideIn {
  from {
    opacity: 0;
    transform: translateY(-8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.semester-row__header {
  grid-column: 1 / -1;
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: -0.25rem;
}

.semester-row__label {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.field-group {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.field-group label {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--color-text-muted);
}

.field-group label .optional {
  font-weight: 400;
  color: var(--color-text-placeholder);
}

.field-group label .required {
  color: var(--color-error);
}

.field-group input {
  width: 100%;
  padding: 0.7rem 0.9rem;
  font-size: 0.875rem;
  border: 2px solid var(--color-border);
  border-radius: var(--radius-xs);
  background: var(--color-surface);
  color: var(--color-text);
  transition: border-color var(--transition), box-shadow var(--transition);
}

.field-group input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(0, 97, 181, 0.15);
}

.field-group input.input--error {
  border-color: var(--color-error);
  background: var(--color-error-bg);
}

.field-group input.input--error:focus {
  box-shadow: 0 0 0 3px rgba(246, 90, 91, 0.12);
}

.field-error {
  font-size: 0.75rem;
  color: var(--color-error);
  min-height: 1.125rem;
  line-height: 1.4;
}

.calculator-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  padding-top: 0.5rem;
  border-top: 1px solid var(--color-border);
}

/* --- Subject-wise Entry Mode --- */
.semester-row--subjects {
  grid-template-columns: 1fr;
}

.subject-list {
  grid-column: 1 / -1;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.subject-row {
  display: grid;
  grid-template-columns: 1.4fr 1fr 0.8fr auto;
  gap: 0.75rem;
  align-items: start;
  padding: 0.9rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xs);
  animation: fadeSlideIn 0.25s ease;
}

.subject-row select.subject-grade {
  width: 100%;
  padding: 0.7rem 0.9rem;
  font-size: 0.875rem;
  border: 2px solid var(--color-border);
  border-radius: var(--radius-xs);
  background: var(--color-surface);
  color: var(--color-text);
  transition: border-color var(--transition), box-shadow var(--transition);
}

.subject-row select.subject-grade:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(0, 97, 181, 0.15);
}

.subject-row .delete-subject-btn {
  margin-top: 1.6rem;
}

.subject-row-actions {
  grid-column: 1 / -1;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 0.25rem;
}

.btn--sm {
  padding: 0.5rem 0.9rem;
  font-size: 0.875rem;
}

.semester-sgpa-display {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.9rem;
  background: rgba(0, 97, 181, 0.06);
  border-radius: var(--radius-xs);
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--color-text-muted);
}

.semester-sgpa-display strong {
  font-size: 1rem;
  color: var(--color-primary);
}

/* --- Result Card --- */
.result-card {
  margin-top: 2rem;
  padding: 1.75rem;
  background: linear-gradient(135deg, var(--color-success-container) 0%, var(--color-success-container-dark) 100%);
  border: 2px solid #54AA92;
  border-radius: var(--radius);
  animation: resultReveal 0.5s ease;
}

@keyframes resultReveal {
  from {
    opacity: 0;
    transform: translateY(12px) scale(0.98);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

.result-card__header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1.25rem;
  color: var(--color-success-dark);
}

.result-card__header h3 {
  font-size: 1.125rem;
  font-weight: 700;
}

.result-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
}

.result-item {
  text-align: center;
  padding: 1.25rem 1rem;
  background: rgba(255, 255, 255, 0.7);
  border-radius: var(--radius-sm);
  backdrop-filter: blur(4px);
}

.result-item--primary {
  background: var(--color-success);
  color: #fff;
}

.result-item--primary .result-item__label {
  color: rgba(255, 255, 255, 0.85);
}

.result-item__label {
  display: block;
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--color-text-muted);
  margin-bottom: 0.35rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.result-item__value {
  display: block;
  font-size: clamp(1.5rem, 4vw, 2rem);
  font-weight: 700;
  letter-spacing: 0px;
}

/* --- Result Breakdown --- */
.result-breakdown {
  margin-top: 1.5rem;
  padding-top: 1.25rem;
  border-top: 1px solid rgba(0, 128, 92, 0.2);
}

.result-breakdown__title {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--color-text-muted);
  margin-bottom: 0.75rem;
}

.result-breakdown__list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.result-breakdown__row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  padding: 0.6rem 0.9rem;
  background: rgba(255, 255, 255, 0.7);
  border-radius: var(--radius-xs);
  font-size: 0.875rem;
}

.result-breakdown__name {
  font-weight: 500;
  color: var(--color-text);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.result-breakdown__sgpa {
  color: var(--color-success-dark);
  font-weight: 700;
}

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

/* ==========================================================================
   Grade Table
   ========================================================================== */
.table-card {
  padding: 0;
  overflow: hidden;
}

.table-wrapper {
  overflow-x: auto;
}

.grade-table {
  width: 100%;
  border-collapse: collapse;
}

.grade-table th,
.grade-table td {
  padding: 1rem 1.5rem;
  text-align: left;
}

.grade-table thead {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
  color: #fff;
}

.grade-table th {
  font-weight: 700;
  font-size: 0.875rem;
  letter-spacing: 0.02em;
}

.grade-table tbody tr {
  border-bottom: 1px solid var(--color-border);
  transition: background-color var(--transition);
}

.grade-table tbody tr:last-child {
  border-bottom: none;
}

.grade-table tbody tr:hover {
  background-color: var(--color-bg);
}

.grade-table td {
  font-size: 0.875rem;
}

.grade-table td:last-child {
  font-weight: 700;
  color: var(--color-primary);
}

.grade-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 2.5rem;
  padding: 0.25rem 0.6rem;
  border-radius: var(--radius-xs);
  font-weight: 700;
  font-size: 0.875rem;
}

.grade-badge--s  { background: #E6F2EF; color: #004633; }
.grade-badge--ap { background: #E6F3FF; color: #004B8C; }
.grade-badge--a  { background: #E6F3FF; color: #004B8C; }
.grade-badge--bp { background: #F2ECF5; color: #462254; }
.grade-badge--b  { background: #F2ECF5; color: #462254; }
.grade-badge--cp { background: #FAF5E7; color: #74570A; }
.grade-badge--c  { background: #FAF5E7; color: #74570A; }
.grade-badge--d  { background: #FFF6E6; color: #8C5800; }
.grade-badge--p  { background: #F9F2F0; color: #694339; }
.grade-badge--lp { background: #FFF6E6; color: #8C5800; }
.grade-badge--f  { background: #FEEFEF; color: #873232; }

.table-footnote {
  padding: 1rem 1.5rem 1.5rem;
  font-size: 0.75rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* ==========================================================================
   Career Guidance CTA
   ========================================================================== */
.section--tight {
  padding-block: 1rem 2rem;
}

.cta-card {
  padding: 1.5rem;
  background: var(--color-primary);
  border-radius: var(--radius-sm);
  text-align: left;
}

.cta-badge {
  display: inline-block;
  background: rgba(255, 255, 255, 0.2);
  color: #fff;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.25rem 0.75rem;
  border-radius: var(--radius-full);
  margin-bottom: 0.75rem;
}

.cta-card h3 {
  color: #fff;
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: 0px;
  margin-bottom: 0.5rem;
}

.cta-card p {
  color: rgba(255, 255, 255, 0.8);
  font-size: 0.875rem;
  line-height: 1.6;
  margin-bottom: 1.25rem;
}

.btn-cta {
  display: inline-flex;
  align-items: center;
  color: #fff;
  font-size: 0.875rem;
  font-weight: 700;
  padding: 0.75rem 1.5rem;
  border: 2px solid #fff;
  border-radius: var(--radius-full);
  transition: background-color var(--transition), color var(--transition);
}

.btn-cta:hover {
  background: #fff;
  color: var(--color-primary);
}

/* ==========================================================================
   Formula Section
   ========================================================================== */
.formula-card {
  padding: 2rem;
}

.formula-box {
  text-align: center;
  padding: 1.75rem;
  background: linear-gradient(135deg, rgba(0, 97, 181, 0.06) 0%, rgba(0, 97, 181, 0.02) 100%);
  border: 2px dashed rgba(0, 97, 181, 0.25);
  border-radius: var(--radius-sm);
  margin-bottom: 2rem;
}

.formula-main {
  font-size: clamp(1.125rem, 3vw, 1.5rem);
  font-weight: 700;
  color: var(--color-primary);
  letter-spacing: 0.15px;
}

.formula-example__title {
  font-size: 1.125rem;
  font-weight: 700;
  margin-bottom: 1.25rem;
  color: var(--color-text);
}

.formula-semesters {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.formula-semester {
  padding: 1rem 1.25rem;
  background: var(--color-bg);
  border-radius: var(--radius-xs);
  border: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  font-size: 0.875rem;
}

.formula-semester strong {
  color: var(--color-primary);
  margin-bottom: 0.25rem;
}

.formula-steps {
  padding: 1.25rem;
  background: var(--color-bg);
  border-radius: var(--radius-xs);
  font-size: 0.875rem;
  line-height: 1.8;
}

.formula-expression {
  font-family: 'Courier New', Courier, monospace;
  color: var(--color-text-muted);
  padding: 0.5rem 0;
  word-break: break-all;
}

.formula-result {
  font-size: 1.25rem;
  color: var(--color-success-dark);
}

.formula-result strong {
  font-size: 1.5rem;
}

/* ==========================================================================
   FAQ Accordion
   ========================================================================== */
.accordion {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.accordion__item {
  background: var(--color-surface);
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
  overflow: hidden;
  transition: box-shadow var(--transition);
}

.accordion__item:hover {
  box-shadow: var(--shadow-sm);
}

.accordion__item--open {
  box-shadow: var(--shadow-md);
  border-color: rgba(0, 97, 181, 0.2);
}

.accordion__trigger {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.25rem 1.5rem;
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-text);
  text-align: left;
  transition: color var(--transition);
}

.accordion__trigger:hover {
  color: var(--color-primary);
}

.accordion__icon {
  flex-shrink: 0;
  transition: transform var(--transition);
  color: var(--color-text-muted);
}

.accordion__item--open .accordion__icon {
  transform: rotate(180deg);
  color: var(--color-primary);
}

.accordion__panel {
  overflow: hidden;
  transition: max-height var(--transition), padding var(--transition);
  max-height: 0;
  padding-inline: 1.5rem;
}

.accordion__item--open .accordion__panel {
  max-height: 300px;
  padding-bottom: 1.25rem;
}

.accordion__panel p {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  line-height: 1.7;
}

/* ==========================================================================
   Footer
   ========================================================================== */
.site-footer {
  background: #121212;
  color: #B2B2B2;
  padding-inline: 1.25rem;
  font-size: 0.875rem;
}

.footer-brand-bar {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1.5rem;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-block: 2.5rem 1.5rem;
}

.footer-brand-left {
  max-width: 480px;
}

.footer-brand-logo {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.75rem;
}

.footer-brand-name {
  font-size: 1.25rem;
  font-weight: 700;
  color: #fff;
}

.footer-brand-desc {
  font-size: 0.875rem;
  line-height: 1.6;
  color: #949494;
}

.footer-brand-right {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 1rem;
}

.footer-social {
  display: flex;
  gap: 0.6rem;
}

.footer-social a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.25rem;
  height: 2.25rem;
  border-radius: var(--radius-full);
  background: rgba(255, 255, 255, 0.08);
  color: #B2B2B2;
  transition: background-color var(--transition), color var(--transition);
}

.footer-social a:hover {
  background: rgba(255, 255, 255, 0.16);
  color: #fff;
}

.footer-play-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.6rem 1.25rem;
  border: 2px solid #fff;
  border-radius: var(--radius-full);
  color: #fff;
  font-size: 0.875rem;
  font-weight: 700;
  transition: background-color var(--transition), color var(--transition);
}

.footer-play-btn:hover {
  background: #fff;
  color: #121212;
}

.footer-divider {
  border: none;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  max-width: var(--container-max);
  margin-inline: auto;
}

.footer-top {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 2rem;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-block: 2rem;
}

.footer-col {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.footer-col-title {
  font-size: 0.75rem;
  font-weight: 700;
  color: #808080;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-top: 0.5rem;
}

.footer-col-title:first-child {
  margin-top: 0;
}

.footer-col a {
  font-size: 0.875rem;
  color: #B2B2B2;
  transition: color var(--transition);
}

.footer-col a:hover {
  color: #fff;
  text-decoration: underline;
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-block: 1.5rem;
  font-size: 0.75rem;
  color: #808080;
}

.footer-legal {
  display: flex;
  gap: 1.5rem;
}

.footer-legal a {
  color: #808080;
  transition: color var(--transition);
}

.footer-legal a:hover {
  color: #fff;
}

.footer-disclaimer-bar {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding: 1rem 0;
  text-align: center;
  font-size: 0.75rem;
  color: #616161;
  line-height: 1.5;
}

/* ==========================================================================
   Sticky Mobile Calculate Button
   ========================================================================== */
.sticky-calc {
  display: none;
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 0.75rem 1.25rem;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(12px);
  border-top: 1px solid var(--color-border);
  box-shadow: 0 -4px 16px rgba(15, 23, 42, 0.08);
  transform: translateY(100%);
  transition: transform var(--transition);
}

.sticky-calc--visible {
  transform: translateY(0);
}

/* ==========================================================================
   Responsive — Tablet
   ========================================================================== */
@media (max-width: 900px) {
  .result-grid {
    grid-template-columns: 1fr;
  }

  .result-item--primary {
    order: -1;
  }
}

/* ==========================================================================
   Responsive — Mobile
   ========================================================================== */
@media (max-width: 768px) {
  .section {
    padding-block: 3rem;
  }

  .site-nav__inner {
    padding: 0.75rem 1rem;
  }

  .mega-menu {
    max-height: calc(100vh - 60px);
    overflow-y: auto;
  }

  .mega-menu__inner {
    grid-template-columns: 1fr;
    gap: 1.5rem;
    padding: 1.5rem 1.25rem 2rem;
  }

  .hero {
    padding-block: 3.5rem 4rem;
  }

  .calculator-card {
    padding: 1.25rem;
  }

  .semester-row {
    grid-template-columns: 1fr 1fr;
    gap: 0.75rem;
  }

  .semester-row .field-group--delete {
    grid-column: 1 / -1;
    display: flex;
    justify-content: flex-end;
  }

  .calculator-actions {
    flex-direction: column;
  }

  .calculator-actions .btn {
    width: 100%;
  }

  /* Hide desktop calculate button on mobile; use sticky instead */
  #calculateBtn {
    display: none;
  }

  .sticky-calc {
    display: block;
  }

  body {
    padding-bottom: 80px;
  }

  .formula-semesters {
    grid-template-columns: 1fr;
  }

  .formula-card {
    padding: 1.25rem;
  }

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

  .subject-row .delete-subject-btn {
    margin-top: 0;
    justify-self: end;
  }

  .subject-row-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .semester-sgpa-display {
    justify-content: space-between;
  }

  .mode-toggle {
    width: 100%;
  }

  .mode-toggle__btn {
    flex: 1;
  }

  .footer-brand-bar {
    flex-direction: column;
  }

  .footer-brand-right {
    align-items: flex-start;
  }

  .footer-top {
    grid-template-columns: 1fr 1fr;
    gap: 2rem 1.5rem;
  }

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (max-width: 480px) {
  .semester-row {
    grid-template-columns: 1fr;
  }

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

  .grade-table th,
  .grade-table td {
    padding: 0.75rem 1rem;
  }

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