/* ============================================================
   ROOT VARIABLES
   ============================================================ */
:root {
  --primary:        #16a34a;
  --primary-dark:   #15803d;
  --primary-light:  rgba(22, 163, 74, 0.09);
  --primary-glow:   rgba(22, 163, 74, 0.16);
  --accent:         #0ea5e9;
  --accent2:        #ea580c;
  --accent3:        #9333ea;
  --bg:             #f0f5f2;
  --bg-card:        #ffffff;
  --bg-card2:       #f7faf8;
  --border:         #cdddd5;
  --border-light:   #daeae2;
  --text:           #0f1e17;
  --text-muted:     #4a7060;
  --font-sans:      'Segoe UI', system-ui, -apple-system, sans-serif;
}

/* ============================================================
   RESET & BASE
   ============================================================ */
*, *::before, *::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-sans);
  font-weight: 800;
}

/* ============================================================
   NAVBAR
   ============================================================ */
.navbar {
  background: rgb(255 255 255 / .97);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(16px);
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: 0 2px 16px rgb(0 0 0 / .06);
}

.navbar-brand {
  font-family: var(--font-sans);
  font-weight: 800;
  font-size: 1.3rem;
  color: var(--text) !important;
  gap: 8px;
  display: flex;
  align-items: center;
}

.brand-dot {
  width: 30px;
  height: 30px;
  background: var(--primary);
  border-radius: 9px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: .9rem;
  box-shadow: 0 3px 10px var(--primary-glow);
}

.navbar-brand span {
  color: var(--primary);
}

.nav-link {
  color: #2d5040 !important;
  font-weight: 500;
  font-size: .9rem;
  border-radius: 8px;
  padding: 6px 14px !important;
  transition: .2s;
}

.nav-link:hover,
.nav-link.active {
  color: var(--primary) !important;
  background: var(--primary-light);
}

.navbar-toggler {
  border: none;
}

/* ============================================================
   HERO
   ============================================================ */
.hero {
  background: linear-gradient(140deg, #e0f5ea 0%, #eef8ff 50%, #fefce8 100%);
  padding: 72px 0 60px;
  border-bottom: 1px solid var(--border);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgb(0 185 107 / .09) 0%, transparent 70%);
  top: -120px;
  right: -80px;
  pointer-events: none;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 30px;
  padding: 5px 14px;
  font-size: .78rem;
  color: var(--text-muted);
  font-weight: 600;
  margin-bottom: 20px;
  box-shadow: 0 2px 8px rgb(0 0 0 / .05);
}

.hero-badge i {
  color: var(--primary);
}

.hero-title {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 800;
  line-height: 1.1;
  margin-bottom: 16px;
  letter-spacing: -1px;
}

.hero-title .hl {
  color: var(--primary);
}

.hero-sub {
  font-size: 1.02rem;
  color: var(--text-muted);
  line-height: 1.7;
  max-width: 560px;
}

.hero-stats {
  display: flex;
  gap: 0;
  margin-top: 36px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
  box-shadow: 0 2px 12px rgb(0 0 0 / .05);
  width: fit-content;
}

.h-stat {
  padding: 14px 28px;
  text-align: center;
  position: relative;
}

.h-stat:not(:last-child)::after {
  content: '';
  position: absolute;
  right: 0;
  top: 18%;
  height: 64%;
  width: 1px;
  background: var(--border);
}

.h-stat-n {
  font-family: var(--font-sans);
  font-size: 1.55rem;
  font-weight: 800;
  color: var(--text);
  line-height: 1;
}

.h-stat-n em {
  font-style: normal;
  color: var(--primary);
}

.h-stat-l {
  font-size: .74rem;
  color: var(--text-muted);
  margin-top: 3px;
  font-weight: 500;
}

/* ============================================================
   CALCULATOR
   ============================================================ */
.calc-wrap {
  padding: 56px 0 40px;
}

.calc-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 24px;
  box-shadow: 0 6px 32px rgb(0 0 0 / .07);
  overflow: hidden;
}

.calc-header {
  background: linear-gradient(135deg, var(--primary), #00d17a);
  padding: 32px 40px 28px;
  position: relative;
  overflow: hidden;
}

.calc-header::after {
  content: '';
  position: absolute;
  right: -40px;
  top: -40px;
  width: 180px;
  height: 180px;
  border-radius: 50%;
  background: rgb(255 255 255 / .08);
}

.calc-header::before {
  content: '';
  position: absolute;
  right: 60px;
  bottom: -30px;
  width: 100px;
  height: 100px;
  border-radius: 50%;
  background: rgb(255 255 255 / .05);
}

.calc-title {
  font-size: 1.6rem;
  font-weight: 800;
  color: #fff;
  margin-bottom: 6px;
}

.calc-sub {
  font-size: .9rem;
  color: rgb(255 255 255 / .8);
}

.calc-body {
  padding: 36px 40px;
}

/* ============================================================
   FORM ELEMENTS
   ============================================================ */
.form-label {
  font-size: .82rem;
  font-weight: 700;
  color: #2d4a3a;
  margin-bottom: 7px;
  letter-spacing: .3px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.form-label i {
  color: var(--primary);
  font-size: .9rem;
}

.field-wrap {
  position: relative;
}

.field-input {
  background: #f5faf7;
  border: 1.5px solid #cce0d5;
  border-radius: 12px;
  color: var(--text);
  padding: 13px 52px 13px 16px;
  font-size: .97rem;
  font-family: var(--font-sans);
  width: 100%;
  transition: border-color .2s, box-shadow .2s, background .2s;
  outline: none;
  appearance: none;
  -webkit-appearance: none;
}

.field-input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-light);
  background: #fff;
}

.field-input::placeholder {
  color: #a8c4b5;
}

.field-unit {
  position: absolute;
  right: 14px;
  top: 50%;
  transform: translateY(-50%);
  font-size: .8rem;
  color: var(--text-muted);
  font-weight: 700;
  pointer-events: none;
}

select.field-input {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' fill='%235a7868' viewBox='0 0 16 16'%3E%3Cpath d='M7.247 11.14L2.451 5.658C1.885 5.013 2.345 4 3.204 4h9.592a1 1 0 0 1 .753 1.659l-4.796 5.48a1 1 0 0 1-1.506 0z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 14px center;
  padding-right: 38px;
  cursor: pointer;
}

.unit-toggle {
  display: flex;
  gap: 8px;
}

.unit-btn {
  flex: 1;
  padding: 11px 8px;
  border: 1.5px solid #cce0d5;
  background: #f5faf7;
  color: var(--text-muted);
  border-radius: 11px;
  font-size: .88rem;
  font-weight: 600;
  cursor: pointer;
  transition: .2s;
  font-family: var(--font-sans);
}

.unit-btn.active {
  background: var(--primary-light);
  border-color: var(--primary);
  color: var(--primary);
}

.unit-btn:hover:not(.active) {
  border-color: #a8c4b5;
  background: #edf5f0;
}

.btn-calc {
  background: linear-gradient(135deg, var(--primary), #00d07a);
  color: #fff;
  font-family: var(--font-sans);
  font-weight: 800;
  font-size: 1.08rem;
  border: none;
  border-radius: 14px;
  padding: 17px 32px;
  width: 100%;
  cursor: pointer;
  transition: transform .15s, box-shadow .2s;
  box-shadow: 0 6px 24px var(--primary-glow);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
}

.btn-calc:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 36px rgb(0 185 107 / .35);
}

.btn-calc:active {
  transform: translateY(0);
}

/* ============================================================
   RESULT PANEL
   ============================================================ */
.result-panel {
  display: none;
  animation: fadeUp .45s ease;
  margin-top: 32px;
}

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(20px); }
  to   { opacity: 1; transform: translateY(0); }
}

.result-hero {
  background: linear-gradient(135deg, rgb(0 185 107 / .07), rgb(56 189 248 / .05));
  border: 1.5px solid rgb(0 185 107 / .2);
  border-radius: 18px;
  padding: 32px 28px;
  text-align: center;
  margin-bottom: 20px;
  position: relative;
  overflow: hidden;
}

.result-hero::before {
  content: '';
  position: absolute;
  width: 200px;
  height: 200px;
  background: radial-gradient(circle, rgb(0 185 107 / .08), transparent);
  top: -60px;
  right: -40px;
}

.result-label-top {
  font-size: .82rem;
  color: var(--text-muted);
  font-weight: 600;
  margin-bottom: 8px;
  letter-spacing: .3px;
}

.result-num {
  font-family: var(--font-sans);
  font-size: 4rem;
  font-weight: 800;
  color: var(--primary);
  line-height: 1;
}

.result-unit {
  font-size: .95rem;
  color: var(--text-muted);
  margin-top: 6px;
  font-weight: 500;
}

.result-equiv {
  font-size: .82rem;
  color: var(--text-muted);
  margin-top: 10px;
  background: rgb(255 255 255 / .7);
  border-radius: 8px;
  padding: 6px 12px;
  display: inline-block;
}

/* ============================================================
   BREAKDOWN GRID
   ============================================================ */
.breakdown-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  margin-bottom: 20px;
}

@media (max-width: 640px) {
  .breakdown-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 400px) {
  .breakdown-grid { grid-template-columns: 1fr; }
}

.bd-card {
  background: #f5faf7;
  border: 1px solid var(--border);
  border-radius: 13px;
  padding: 16px 12px;
  text-align: center;
  transition: .2s;
}

.bd-card:hover {
  border-color: rgb(0 185 107 / .3);
  background: #edf5f0;
}

.bd-icon {
  font-size: 1.6rem;
  margin-bottom: 6px;
  line-height: 1;
}

.bd-val {
  font-family: var(--font-sans);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text);
}

.bd-label {
  font-size: .73rem;
  color: var(--text-muted);
  margin-top: 3px;
  font-weight: 500;
}

/* ============================================================
   HYDRATION BAR
   ============================================================ */
.hydro-bar-box {
  background: #f5faf7;
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 20px 22px;
  margin-bottom: 20px;
}

.hydro-bar-top {
  display: flex;
  justify-content: space-between;
  font-size: .82rem;
  margin-bottom: 10px;
}

.hydro-bar-track {
  height: 10px;
  background: #d8e9df;
  border-radius: 10px;
  overflow: hidden;
}

.hydro-bar-fill {
  height: 100%;
  border-radius: 10px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  transition: width 1.1s cubic-bezier(.4, 0, .2, 1);
}

.hydro-segs {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
  margin-top: 14px;
}

@media (max-width: 540px) {
  .hydro-segs { grid-template-columns: 1fr 1fr; }
}

.h-seg {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px 8px;
  text-align: center;
  font-size: .76rem;
  color: var(--text-muted);
}

.h-seg strong {
  display: block;
  font-family: var(--font-sans);
  font-size: 1rem;
  color: var(--text);
  margin-bottom: 2px;
}

/* ============================================================
   DISCLAIMER
   ============================================================ */
.disclaimer {
  background: rgb(239 68 68 / .05);
  border: 1px solid rgb(239 68 68 / .15);
  border-radius: 11px;
  padding: 14px 16px;
  font-size: .8rem;
  color: #b91c1c;
  margin-top: 16px;
  display: flex;
  gap: 8px;
  align-items: flex-start;
}

.disclaimer i {
  flex-shrink: 0;
  margin-top: 1px;
}

/* ============================================================
   SECTION / FEATURES
   ============================================================ */
.section-wrap {
  padding: 64px 0;
}

.sec-title {
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--text);
  margin-bottom: 8px;
}

.sec-sub {
  font-size: .93rem;
  color: var(--text-muted);
  max-width: 520px;
  margin: 0 auto;
  line-height: 1.65;
}

.feature-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 26px 22px;
  box-shadow: 0 2px 10px rgb(0 0 0 / .04);
  transition: .25s;
  height: 100%;
}

.feature-card:hover {
  border-color: rgb(0 185 107 / .35);
  box-shadow: 0 6px 24px rgb(0 185 107 / .1);
  transform: translateY(-3px);
}

.f-icon {
  width: 50px;
  height: 50px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  margin-bottom: 16px;
}

.f-icon-green  { background: rgb(0 185 107 / .1); }
.f-icon-blue   { background: rgb(56 189 248 / .1); }
.f-icon-yellow { background: rgb(251 191 36 / .1); }
.f-icon-purple { background: rgb(167 139 250 / .1); }

.f-title {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--text);
}

.f-desc {
  font-size: .85rem;
  color: var(--text-muted);
  line-height: 1.65;
}

/* ============================================================
   BLOG / GUIDES
   ============================================================ */
.blog-section {
  padding: 64px 0;
  background: var(--bg);
  border-top: 1px solid var(--border);
}

.blog-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
}

@media (max-width: 1100px) { .blog-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 600px)  { .blog-grid { grid-template-columns: 1fr; } }

.blog-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: .25s;
  opacity: 0;
  transform: translateY(16px);
}

.blog-card.visible {
  opacity: 1;
  transform: translateY(0);
  transition: opacity .4s ease, transform .4s ease, border-color .25s, box-shadow .25s;
}

.blog-card:hover {
  border-color: rgb(22 163 74 / .3);
  box-shadow: 0 6px 24px rgb(22 163 74 / .1);
  transform: translateY(-3px);
}

.blog-thumb {
  width: 100%;
  height: 130px;
  object-fit: cover;
  background: linear-gradient(135deg, #e8f5ee, #eef4ff);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.5rem;
  flex-shrink: 0;
}

.blog-content {
  padding: 16px;
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.blog-badge {
  display: inline-block;
  font-size: .68rem;
  font-weight: 700;
  letter-spacing: .5px;
  text-transform: uppercase;
  padding: 2px 9px;
  border-radius: 20px;
  background: var(--primary-light);
  color: var(--primary);
  border: 1px solid rgb(22 163 74 / .2);
  width: fit-content;
}

.blog-badge.blue   { background: rgb(14 165 233 / .08); color: var(--accent);  border-color: rgb(14 165 233 / .2); }
.blog-badge.orange { background: rgb(234 88 12 / .08);  color: var(--accent2); border-color: rgb(234 88 12 / .2); }
.blog-badge.purple { background: rgb(147 51 234 / .08); color: var(--accent3); border-color: rgb(147 51 234 / .2); }

.blog-title {
  font-size: .88rem;
  font-weight: 700;
  color: var(--text);
  line-height: 1.4;
}

.blog-excerpt {
  font-size: .77rem;
  color: var(--text-muted);
  line-height: 1.55;
  flex: 1;
}

.blog-read {
  margin-top: auto;
  font-size: .76rem;
  font-weight: 700;
  color: var(--primary);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  transition: .2s;
}

.blog-read:hover {
  color: #22cc4e;
  gap: 7px;
}

.load-more-btn {
  display: block;
  margin: 36px auto 0;
  padding: 13px 36px;
  background: transparent;
  border: 1.5px solid var(--border);
  border-radius: 12px;
  color: var(--text-muted);
  font-size: .9rem;
  font-weight: 600;
  font-family: var(--font-sans);
  cursor: pointer;
  transition: .2s;
}

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

.load-more-btn.done {
  border-color: var(--border);
  color: var(--text-muted);
  cursor: default;
  opacity: .5;
}

/* ============================================================
   FAQ
   ============================================================ */
.faq-item {
  border: 1px solid var(--border);
  border-radius: 13px;
  margin-bottom: 10px;
  overflow: hidden;
}

.faq-q {
  width: 100%;
  text-align: left;
  padding: 17px 20px;
  cursor: pointer;
  font-weight: 600;
  font-size: .93rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: #fff;
  transition: .2s;
  color: var(--text);
  border: none;
  outline: none;
}

.faq-q:hover { background: #f5faf7; }

.faq-q:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: -2px;
}

.faq-a {
  display: none;
  padding: 16px 20px;
  font-size: .87rem;
  color: var(--text-muted);
  line-height: 1.7;
  background: #f9fcfb;
  border-top: 1px solid var(--border);
}

.faq-a.open {
  display: block;
  animation: fadeDown .25s ease;
}

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

.faq-icon {
  transition: transform .3s;
  font-size: .9rem;
  color: var(--text-muted);
  flex-shrink: 0;
}

.faq-item.open .faq-icon {
  transform: rotate(45deg);
}

/* ============================================================
   FOOTER
   ============================================================ */
footer {
  background: #0f1e16;
  border-top: 1px solid rgb(255 255 255 / .07);
  padding: 30px 0 24px;
}

.footer-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 14px;
}

.footer-row p,
.footer-row a {
  font-size: .8rem;
  color: #5a7868;
  margin: 0;
}

.footer-row a {
  text-decoration: none;
  transition: .2s;
}

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

.footer-logo {
  font-family: var(--font-sans);
  font-weight: 800;
  color: #fff;
  font-size: 1rem;
}

.footer-logo span { color: var(--primary); }

/* ============================================================
   SCROLL TO TOP
   ============================================================ */
.scroll-top {
  position: fixed;
  bottom: 24px;
  right: 24px;
  width: 44px;
  height: 44px;
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: 12px;
  font-size: 1.1rem;
  cursor: pointer;
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 999;
  box-shadow: 0 4px 16px var(--primary-glow);
  transition: .2s;
}

.scroll-top:hover {
  background: var(--primary-dark);
  transform: translateY(-2px);
}

/* ============================================================
   UTILITIES
   ============================================================ */
.text-primary-c { color: var(--primary) !important; }

/* ============================================================
   CALCULATOR RESPONSIVE
   ============================================================ */
@media (max-width: 991px) {
  .calc-body   { padding: 28px 24px; }
  .calc-header { padding: 26px 24px; }
}

@media (max-width: 575px) {
  .calc-body   { padding: 22px 18px; }
  .calc-header { padding: 22px 18px; }
  .result-num  { font-size: 3rem; }
}

/* ============================================================
   ARTICLE / BLOG POST
   ============================================================ */
.article-wrap {
  padding: 56px 0 72px;
}

.breadcrumb-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: .8rem;
  color: var(--text-muted);
  margin-bottom: 28px;
  flex-wrap: wrap;
}

.article-body a,
.breadcrumb-bar a {
  color: var(--primary);
  text-decoration: none;
  font-weight: 600;
}

.article-body a:hover,
.breadcrumb-bar a:hover {
  text-decoration: underline;
}

.breadcrumb-bar span { color: #b0c9bc; }

.article-thumb {
  width: 100%;
  height: 200px;
  border-radius: 16px;
  background: linear-gradient(135deg, #d1fae5 0%, #e0f2fe 60%, #fef9c3 100%);
  margin-bottom: 28px;
  border: 1px solid var(--border);
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  margin-bottom: 20px;
}

.article-meta-txt { font-size: .78rem; color: var(--text-muted); }
.article-meta-dot { color: #cce0d5; }

.article-h1 {
  font-size: clamp(1.6rem, 3.2vw, 2.4rem);
  font-weight: 800;
  color: var(--text);
  line-height: 1.15;
  margin-bottom: 14px;
  letter-spacing: -.5px;
}

.article-h1 .hl { color: var(--primary); }

.article-lead {
  font-size: 1.02rem;
  color: var(--text-muted);
  line-height: 1.75;
  margin-bottom: 32px;
  padding-bottom: 28px;
  border-bottom: 1px solid var(--border);
}

.article-body h2 {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--text);
  margin: 40px 0 10px;
  letter-spacing: -.2px;
  scroll-margin-top: 90px;
}

.article-body h2:first-child { margin-top: 0; }

.article-body h3 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text);
  margin: 22px 0 8px;
}

.article-body p {
  font-size: .925rem;
  color: var(--text-muted);
  line-height: 1.82;
  margin-bottom: 14px;
}

.article-body p:last-child { margin-bottom: 0; }

.article-body .sec-divider {
  border: none;
  border-top: 1px solid var(--border-light);
  margin: 36px 0;
}

.article-highlight {
  background: var(--primary-light);
  border-left: 3px solid var(--primary);
  border-radius: 0 12px 12px 0;
  padding: 16px 20px;
  margin: 22px 0;
}

.article-highlight p {
  font-size: .9rem;
  font-weight: 600;
  color: #1a5c35;
  line-height: 1.7;
  margin: 0;
}

.article-note {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 18px 20px;
  margin: 22px 0;
}

.article-note h3 {
  font-size: .78rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: .6px;
  color: var(--text-muted);
  margin: 0 0 10px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-light);
}

.article-note p {
  font-size: .87rem;
  color: var(--text-muted);
  line-height: 1.72;
  margin-bottom: 8px;
}

.article-note p:last-child { margin-bottom: 0; }

/* ============================================================
   TOC (Table of Contents)
   — Desktop: sticky sidebar
   — Mobile: collapsible accordion
   ============================================================ */
.toc-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 22px 20px;
  box-shadow: 0 2px 12px rgba(0, 0, 0, .05);
  position: sticky;
  top: 80px;
  margin-bottom: 24px;
}

.toc-card h4 {
  font-size: .78rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: .7px;
  color: var(--text);
  margin-bottom: 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border);
}

.toc-card ol {
  padding-left: 18px;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.toc-card ol li a {
  font-size: .82rem;
  color: var(--text-muted);
  text-decoration: none;
  font-weight: 500;
  display: block;
  padding: 4px 0;
  transition: .2s;
  line-height: 1.45;
}

.toc-card ol li a:hover  { color: var(--primary); }
.toc-card ol li a.active { color: var(--primary); font-weight: 700; }

.toc-toggle-icon { display: none; }

@media (max-width: 991px) {
  .toc-card {
    position: static;
    padding: 0;
    border-radius: 14px;
    overflow: hidden;
    margin-bottom: 8px;
  }

  .toc-card h4 {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin: 0;
    padding: 14px 18px;
    border-bottom: none;
    cursor: pointer;
    user-select: none;
    font-size: .82rem;
  }

  .toc-toggle-icon {
    display: inline-flex;
    font-size: .85rem;
    color: var(--text-muted);
    transition: transform .28s ease;
    flex-shrink: 0;
  }

  .toc-card.toc-open .toc-toggle-icon {
    transform: rotate(180deg);
  }

  .toc-body {
    max-height: 0;
    overflow: hidden;
    transition: max-height .32s ease, padding .28s ease;
    padding: 0 18px;
  }

  .toc-card.toc-open .toc-body {
    max-height: 500px;
    padding: 0 18px 14px;
  }

  .toc-card ol         { padding-left: 16px; }
  .toc-card ol li a    { padding: 6px 0; font-size: .85rem; }
}