:root {--falsa: #7B5AA6;      /* Deep Violet/Purple */
        --zarda: #C8B08A;       /* Warm Latte/Gold Accent */
        --light-bg: #F4E9FF; /* Lightest Lavender background */
        --mid-lavender: #DCC7F7; /* Light Violet */
        --accent-violet: #B89BE0;/* Medium Violet */
        --text-dark: #2D1B2D;
        --text-light: #6E5A6E;
        --white: #ffffff;}
* {margin: 0; padding: 0; box-sizing: border-box;}
body {background-color: var(--white); color: var(--text-dark); overflow-x: hidden;
font-family: 'Poppins', sans-serif;}
.logo {font-family: 'Space Grotesk', sans-serif; text-decoration: none; display: flex;
align-items: center; gap: 10px;}
.logo-icon {background: var(--falsa); color: var(--white); width: 42px; height: 42px; display:
flex; justify-content: center; align-items: center; border-radius: 10px; font-size: 22px;
box-shadow: 0 4px 10px rgba(123, 90, 166, 0.2);}
.logo-text-group {display: flex; flex-direction: column;}
.logo-main {font-size: 18px; font-weight: 700; color: var(--falsa); letter-spacing: 0.5px;
text-transform: uppercase;}
.logo-sub {font-size: 11px; font-weight: 600; color: var(--zarda); letter-spacing: 1px;
text-transform: uppercase;}
header {display: flex; justify-content: space-between; align-items: center; padding: 20px
5%; background: var(--white); box-shadow: 0 2px 10px rgba(123, 90, 166, 0.05); position:
relative;}
.mobile-menu-btn {display: none; font-size: 28px; background: none; border: none; color:
var(--falsa); cursor: pointer;}
.nav-links {list-style: none; display: flex; gap: 30px; align-items: center;}
.nav-links li a {text-decoration: none; color: var(--text-dark); font-weight: 600; font-size:
15px; transition: color 0.3s;}
.nav-links li a:hover {color: var(--zarda);}
.btn-demo {background: var(--zarda); color: var(--white); padding: 10px 24px;
border-radius: 8px; text-decoration: none; font-weight: 700; font-size: 15px; transition:
background 0.3s; display: inline-flex; align-items: center; justify-content: center;}
.btn-demo:hover {background: #b59b72;}
.subtitle {color: var(--zarda); font-weight: 700; font-size: 14px; letter-spacing: 1px;
text-transform: uppercase; margin-bottom: 15px; display: block;}
.btn-primary {background: var(--falsa); color: var(--white); padding: 12px 28px;
border-radius: 8px; text-decoration: none; font-weight: 600; text-align: center; transition:
transform 0.3s; display: inline-flex; align-items: center; justify-content: center;}
.btn-primary:hover {transform: translateY(-2px); background: #6a4c91;}
.btn-secondary {background: var(--white); color: var(--falsa); border: 2px solid
var(--mid-lavender); padding: 12px 28px; border-radius: 8px; text-decoration: none; font-weight:
600; display: flex; align-items: center; justify-content: center; gap: 8px; transition: all 0.3s;}
.btn-secondary:hover {border-color: var(--zarda); background: var(--light-bg);}
.stats {background: var(--falsa); color: var(--white); display: grid; grid-template-columns:
repeat(4, 1fr); gap: 20px; padding: 40px 5%; text-align: center;}
.stats.stats-quote {display: block;}
.quote-box {max-width: 800px; margin: 0 auto;}
.quote-text {font-family: 'Space Grotesk', sans-serif; font-size: 24px; font-style: italic; line-height: 1.5; color: var(--white);}
.quote-by {display: block; margin-top: 12px; font-size: 14px; letter-spacing: 1px; color: var(--zarda);}
.stat-item h3 {font-size: 32px; color: var(--zarda); margin-bottom: 5px; font-family: 'Space Grotesk', sans-serif;}
.stat-item p {font-size: 14px; opacity: 0.9;}
.courses {padding: 80px 5%; text-align: center;}
.courses h2 {font-size: 32px; color: var(--falsa); margin-bottom: 40px; font-family: 'Space Grotesk', sans-serif;}
.course-grid {display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
gap: 30px;}
.course-card {background: var(--white); border: 1px solid var(--mid-lavender);
border-radius: 14px; padding: 30px; transition: all 0.3s ease; text-align: center; cursor: pointer;}
.course-card:hover {border-color: var(--zarda); transform: translateY(-5px); box-shadow: 0
10px 30px rgba(123, 90, 166, 0.12);}
.course-icon {font-size: 40px; margin-bottom: 20px; color: var(--falsa); background:
var(--light-bg); width: 70px; height: 70px; display: flex; align-items: center; justify-content: center;
margin-left: auto; margin-right: auto; border-radius: 50%;}
.course-card h3 {font-size: 20px; color: var(--falsa); margin-bottom: 15px; font-family:
'Space Grotesk', sans-serif;}
.course-card p {color: var(--text-light); font-size: 14px; margin-bottom: 20px; line-height:
1.5;}
.course-link {color: var(--falsa); font-weight: 600; text-decoration: none; font-size: 14px;}
.sub-dashboard {padding: 60px 5%; min-height: 70vh;}
.back-btn {background: var(--light-bg); border: 2px solid var(--mid-lavender); color:
var(--falsa); padding: 8px 16px; border-radius: 8px; font-weight: 600; cursor: pointer;
margin-bottom: 30px; transition: all 0.3s;}
.back-btn:hover {background: var(--zarda); color: var(--white); border-color: var(--zarda);}
.sub-grid {display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap:
30px; margin-top: 30px;}
.sub-card {background: var(--white); border: 2px solid var(--mid-lavender); border-radius:
16px; padding: 40px 30px; text-align: center; cursor: pointer; transition: all 0.3s;}
.sub-card:hover {border-color: var(--zarda); transform: translateY(-5px); box-shadow: 0
10px 30px rgba(123, 90, 166, 0.1);}
.sub-card h3 {color: var(--falsa); font-size: 22px; margin-bottom: 10px; font-family: 'Space Grotesk', sans-serif;}
.sub-card p {color: var(--text-light); font-size: 14px;}
.chapter-grid {display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 20px; margin-top: 30px;}
.chapter-card {background: var(--white); border: 2px solid var(--mid-lavender); border-radius: 14px; padding: 20px; display: flex; flex-direction: column; justify-content: space-between; box-shadow: 0 4px 10px rgba(123,90,166,0.05); transition: all 0.3s;}
.chapter-card:hover {border-color: var(--zarda); transform: translateY(-3px); box-shadow: 0 10px 20px rgba(123,90,166,0.12);}
.chapter-num {font-size: 12px; font-weight: 700; color: var(--zarda); text-transform: uppercase; margin-bottom: 5px; display: block;}
.chapter-card h3 {color: var(--falsa); font-size: 16px; margin-bottom: 15px; line-height: 1.3;}
.open-btn {background-color: var(--falsa); color: var(--white); border: none; padding: 10px; border-radius: 8px; font-weight: 600; cursor: pointer; text-align: center; width: 100%; font-size: 14px; transition: background 0.3s;}
.open-btn:hover {background-color: #6a4c91;}
.quiz-open-btn {background-color: var(--zarda); color: var(--text-dark); border: none; padding: 10px; border-radius: 8px; font-weight: 600; cursor: pointer; text-align: center; width: 100%; font-size: 14px; transition: background 0.3s;}
.quiz-open-btn:hover {background-color: #b59b72;}
.chapters-empty {text-align: center; padding: 60px 20px; color: var(--text-light); background: var(--light-bg); border-radius: 16px; margin-top: 30px; font-size: 15px;}
.quiz-section {padding: 80px 5%; background-color: var(--light-bg); text-align: center;}
.quiz-container {max-width: 700px; margin: 40px auto 0 auto; background: var(--white);
padding: 40px; border-radius: 16px; border: 2px solid var(--mid-lavender); text-align: left;}
.quiz-question {font-size: 18px; font-weight: 600; color: var(--falsa); margin-bottom: 20px;}
.quiz-options {display: flex; flex-direction: column; gap: 12px; margin-bottom: 25px;}
.quiz-option {background: var(--light-bg); border: 2px solid var(--mid-lavender); padding:
12px 20px; border-radius: 8px; cursor: pointer; font-weight: 500;}
.quiz-option:hover {border-color: var(--zarda); background: #FAF5FF;}
.quiz-option.correct {background: #d4edda !important; border-color: #28a745 !important;
color: #155724 !important;}
.quiz-option.incorrect {background: #f8d7da !important; border-color: #dc3545 !important;
color: #721c24 !important;}
.quiz-result {font-weight: 600; margin-top: 15px; font-size: 16px;}
@media (max-width: 900px) {
  .stats {grid-template-columns: repeat(2, 1fr); gap: 30px;}
}
@media (max-width: 768px) {
  .mobile-menu-btn {display: block;}
  .nav-links {display: none; position: absolute; top: 100%; left: 0; width: 100%;
background: var(--white); flex-direction: column; padding: 20px 0; box-shadow: 0 10px 20px
rgba(0,0,0,0.1); border-top: 1px solid var(--mid-lavender); z-index: 1000; gap: 0;}
  .nav-links li {width: 100%; text-align: center;}
  .nav-links li a {display: block; padding: 12px 20px;}
  .nav-links.active {display: flex;}
  .btn-demo {display: none;}
  .courses h2 {font-size: 26px;}
  .course-grid {grid-template-columns: 1fr;}
  .sub-grid {grid-template-columns: 1fr;}
  .chapter-grid {grid-template-columns: 1fr;}
  .quiz-container {padding: 20px;}
}
@media (max-width: 480px) {
  header {padding: 15px 5%;}
  .logo-icon {width: 36px; height: 36px; font-size: 18px;}
  .logo-main {font-size: 15px;}
  .logo-sub {font-size: 9px;}
  .stats {grid-template-columns: 1fr; gap: 25px; padding: 30px 5%;}
  .courses {padding: 50px 5%;}
  .course-card {padding: 22px;}
  .sub-dashboard {padding: 40px 5%;}
  .sub-card {padding: 28px 20px;}
  .quiz-section {padding: 50px 5%;}
  .quiz-container {padding: 18px;}
  .quiz-question {font-size: 16px;}
}
@media (min-width: 1400px) {
  header, .stats, .courses, .sub-dashboard, .quiz-section {padding-left: 8%;
padding-right: 8%;}
}
@media (hover: none) and (pointer: coarse) {
  .btn-demo, .btn-primary, .btn-secondary, .course-card, .sub-card, .quiz-option, .back-btn, .mobile-menu-btn, .nav-links li a, .open-btn, .quiz-open-btn {min-height: 44px;}
}
.footer {background: var(--falsa); color: var(--white); text-align: center; padding: 30px 5%; font-size: 14px;}
.footer a {color: var(--zarda); text-decoration: none;}
.tool-banner {background: linear-gradient(135deg, var(--falsa) 0%, #4f3868 100%); padding: 60px 5%;}
.tool-banner-inner {max-width: 1100px; margin: 0 auto; display: flex; align-items: center; gap: 40px;}
.tool-banner-icon {font-size: 54px; background: rgba(255,255,255,0.12); width: 110px; height: 110px; border-radius: 50%; display: flex; align-items: center; justify-content: center; flex-shrink: 0; border: 3px solid var(--zarda);}
.tool-banner-text .subtitle {color: var(--zarda);}
.tool-banner-text h2 {font-family: 'Space Grotesk', sans-serif; font-size: 30px; margin: 8px 0 12px; color: var(--white);}
.tool-banner-text p {color: rgba(255,255,255,0.85); font-size: 15px; line-height: 1.6; margin-bottom: 22px; max-width: 560px;}
.tool-banner-text .btn-primary {background: var(--zarda); color: var(--text-dark);}
.tool-banner-text .btn-primary:hover {background: #b59b72; transform: translateY(-2px);}
@media (max-width: 768px) {
  .tool-banner-inner {flex-direction: column; text-align: center; gap: 20px;}
  .tool-banner-text p {margin-left: auto; margin-right: auto;}
}
/* ================= Hero (home) ================= */
:root {--falsa-dark: #4a2f7a;}
.hero {position: relative; overflow: hidden; display: flex; align-items: center; min-height: 600px; padding: 56px 5% 52px;
  background: radial-gradient(640px 400px at 2% 100%, rgba(220,199,247,0.55), transparent 70%),
              linear-gradient(135deg, #faf6ff 0%, #ffffff 48%, #f6f0ff 100%);}
.hero-text {position: relative; z-index: 2; width: min(46%, 600px);}
.hero-eyebrow {display: inline-flex; align-items: center; gap: 12px; color: var(--zarda); font-weight: 700; font-size: 15px; letter-spacing: 0.16em; text-transform: uppercase; margin-bottom: 18px;}
.hero-eyebrow::before, .hero-eyebrow::after {content: ""; width: 26px; height: 2px; background: var(--zarda); border-radius: 2px;}
.hero-text h1 {font-family: 'Space Grotesk', sans-serif; font-weight: 700; font-size: clamp(40px, 5vw, 68px); line-height: 1.06; letter-spacing: -0.02em; margin-bottom: 22px;}
.hero-text h1 span {display: block;}
.hero-text h1 .h1-a {color: var(--falsa-dark);}
.hero-text h1 .h1-b {color: var(--falsa);}
.hero-text p {color: var(--text-light); font-size: 16.5px; line-height: 1.7; max-width: 470px; margin-bottom: 30px;}
.hero-buttons {display: flex; gap: 14px; flex-wrap: wrap;}
.hero-buttons .btn-primary {gap: 10px; padding: 14px 28px; box-shadow: 0 8px 20px rgba(123, 90, 166, 0.28);}
.hero-buttons .btn-secondary {padding: 14px 26px;}
.hero-tools {display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; margin-top: 30px; max-width: 500px;}
.tool-chip {display: flex; align-items: center; gap: 12px; padding: 12px 14px; border-radius: 12px; text-decoration: none; background: rgba(255,255,255,0.85); border: 1px solid var(--mid-lavender); box-shadow: 0 4px 14px rgba(123, 90, 166, 0.07); transition: border-color .25s, transform .25s, box-shadow .25s;}
.tool-chip:hover, .tool-chip:focus-visible {border-color: var(--zarda); transform: translateY(-2px); box-shadow: 0 10px 24px rgba(123, 90, 166, 0.14);}
.tool-chip-icon {flex-shrink: 0; width: 40px; height: 40px; border-radius: 10px; display: grid; place-items: center; color: var(--falsa); background: var(--light-bg);}
.tool-chip-text {display: flex; flex-direction: column; min-width: 0;}
.tool-chip-text strong {color: var(--falsa-dark); font-size: 14px; font-weight: 600; line-height: 1.3;}
.tool-chip-text small {color: var(--text-light); font-size: 12px; line-height: 1.4;}
/* artwork: fades into the page background on the left and top */
.hero-art {position: absolute; right: -2%; bottom: 0; width: clamp(560px, 68vw, 1020px); z-index: 1; pointer-events: none;
  -webkit-mask-image: linear-gradient(to right, transparent 0, #000 17%), linear-gradient(to bottom, transparent 0, #000 10%);
  -webkit-mask-composite: source-in;
  mask-image: linear-gradient(to right, transparent 0, #000 17%), linear-gradient(to bottom, transparent 0, #000 10%);
  mask-composite: intersect; animation: heroArtIn .9s ease-out both;}
.hero-art img {display: block; width: 100%; height: auto;}
@keyframes heroArtIn {from { opacity: 0; transform: translateX(18px); } to { opacity: 1; transform: none; }}
@media (prefers-reduced-motion: reduce) {
  .hero-art {animation: none;}
}
.hero-curve {position: absolute; left: 0; bottom: 0; width: 22%; height: 150px; fill: none; stroke: var(--zarda); stroke-width: 1.4; opacity: .7; pointer-events: none;}
.hero-curve path {vector-effect: non-scaling-stroke;}
.tool-chip:focus-visible, .btn-primary:focus-visible, .btn-secondary:focus-visible {outline: 2px solid var(--falsa); outline-offset: 3px;}
@media (max-width: 1000px) {
  .hero {flex-direction: column; align-items: stretch; min-height: 0; padding: 40px 5% 0;}
  .hero-text {width: 100%; max-width: 640px; margin: 0 auto; text-align: center;}
  .hero-eyebrow {justify-content: center;}
  .hero-text p {margin-left: auto; margin-right: auto;}
  .hero-buttons {justify-content: center;}
  .hero-tools {margin-left: auto; margin-right: auto; text-align: left;}
  .hero-art {position: relative; right: auto; width: 116%; margin: 26px -8% 0 -8%; max-width: none;}
  .hero-curve {display: none;}
}
@media (max-width: 560px) {
  .hero {padding-top: 30px;}
  .hero-text h1 {font-size: 36px;}
  .hero-text p {font-size: 15px;}
  .hero-buttons {flex-direction: column;}
  .hero-buttons a {width: 100%;}
  .hero-tools {grid-template-columns: 1fr;}
  .hero-art {width: 150%; margin: 18px -25% 0 -25%;}
}
@media (min-width: 1400px) {
  .hero {padding-left: 8%; padding-right: 8%;}
}
/* ================= Periodic table page ================= */
.visually-hidden {position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap;}
.pt-cell, .pt-legend-btn, .pt-placeholder {--c: var(--falsa);}
.cat-alkali {--c: #E0894A;}
.cat-alkaline {--c: #C8B08A;}
.cat-transition {--c: #7B5AA6;}
.cat-post {--c: #5B84C4;}
.cat-metalloid {--c: #3FA58A;}
.cat-nonmetal {--c: #6BAA45;}
.cat-halogen {--c: #D65C82;}
.cat-noble {--c: #A45FD0;}
.cat-lanthanide {--c: #2FA3BD;}
.cat-actinide {--c: #B8726B;}
.pt-page {max-width: 1360px; margin: 0 auto; padding: 32px 5% 70px;}
.pt-title {font-family: 'Space Grotesk', sans-serif; font-size: clamp(30px, 4vw, 42px); color: var(--falsa-dark); letter-spacing: -0.01em; margin-bottom: 8px;}
.pt-lede {color: var(--text-light); font-size: 15px; margin-bottom: 20px; max-width: 640px; line-height: 1.6;}
.pt-controls {display: flex; flex-wrap: wrap; gap: 14px 20px; align-items: center; margin-bottom: 22px;}
.pt-search {display: flex; align-items: center; gap: 10px; background: var(--white); border: 2px solid var(--mid-lavender); border-radius: 10px; padding: 0 14px; color: var(--text-light); min-width: 280px;}
.pt-search:focus-within {border-color: var(--falsa);}
.pt-search input {flex: 1; background: none; border: 0; outline: 0; color: var(--text-dark); font: inherit; font-size: 14px; padding: 11px 0; min-width: 0;}
.pt-legend {display: flex; flex-wrap: wrap; gap: 8px;}
.pt-legend-btn {display: inline-flex; align-items: center; gap: 8px; background: var(--white); border: 1px solid var(--mid-lavender); color: var(--text-dark); font: inherit; font-size: 12px; padding: 5px 11px; border-radius: 999px; cursor: pointer; transition: border-color .2s, background .2s;}
.pt-legend-btn i {width: 10px; height: 10px; border-radius: 3px; background: var(--c);}
.pt-legend-btn:hover {border-color: var(--c);}
.pt-legend-btn[aria-pressed="true"] {border-color: var(--c); background: color-mix(in srgb, var(--c) 16%, #fff);}
.pt-scroll {overflow-x: auto; padding: 4px 5% 10px; margin: 0 -5%;}
.pt-grid {--ch: clamp(46px, 4.6vw, 64px); display: grid; grid-template-columns: 22px repeat(18, minmax(0, 1fr)); grid-template-rows: 20px repeat(7, var(--ch)) 14px repeat(2, var(--ch)); gap: 4px; min-width: 900px;}
.pt-axis {display: grid; place-items: center; font-size: 11px; color: var(--text-light); opacity: .8;}
.pt-cell {position: relative; display: flex; flex-direction: column; justify-content: space-between; align-items: center; padding: 3px 2px 4px; border-radius: 6px; cursor: pointer; font-family: 'Space Grotesk', sans-serif;
  background: color-mix(in srgb, var(--c) 13%, #fff); border: 1px solid color-mix(in srgb, var(--c) 50%, #fff); transition: background .15s, opacity .2s, transform .15s, box-shadow .15s; min-width: 0;}
@media (hover: hover) {
  .pt-cell:hover {background: color-mix(in srgb, var(--c) 26%, #fff); z-index: 2; transform: scale(1.08); box-shadow: 0 6px 14px rgba(123, 90, 166, 0.18);}
}
.pt-cell:focus-visible {outline: 2px solid var(--falsa-dark); outline-offset: 2px; z-index: 3;}
.pt-cell .n {align-self: flex-start; font-size: 9.5px; line-height: 1; color: var(--text-light); padding-left: 3px;}
.pt-cell .s {font-size: clamp(15px, 1.6vw, 21px); font-weight: 700; line-height: 1; color: color-mix(in srgb, var(--c) 70%, #2D1B2D);}
.pt-cell .nm {font-size: 8.5px; line-height: 1; color: var(--text-light); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; max-width: 100%;}
.pt-cell.selected {background: color-mix(in srgb, var(--c) 30%, #fff); border-color: var(--c); box-shadow: 0 0 0 2px var(--c); z-index: 2;}
.pt-cell.dim {opacity: 0.18;}
.pt-placeholder {display: grid; place-items: center; font-size: 10px; color: color-mix(in srgb, var(--c) 75%, #2D1B2D); border: 1px dashed color-mix(in srgb, var(--c) 65%, #fff); border-radius: 6px; background: color-mix(in srgb, var(--c) 7%, #fff);}
.pt-series-label {display: flex; align-items: center; justify-content: flex-end; padding-right: 8px; font-size: 11px; color: var(--text-light);}
.pt-hint {display: none; align-items: center; justify-content: space-between; gap: 12px; margin: -6px 0 12px; font-size: 13px; color: var(--text-light); line-height: 1.5;}
.pt-zoom {display: none; align-items: center; gap: 6px; flex-shrink: 0; background: var(--white); border: 2px solid var(--mid-lavender); color: var(--falsa); font: inherit; font-size: 12.5px; font-weight: 600; padding: 7px 12px; border-radius: 999px; cursor: pointer;}
.pt-zoom[aria-pressed="true"] {background: var(--light-bg); border-color: var(--falsa);}
@media (max-width: 1399px) {
  .pt-hint {display: flex;}
}
@media (max-width: 1000px) {
  .pt-cell .nm {display: none;}
}
@media (max-width: 640px) {
  .pt-search {min-width: 100%;}
}
/* ===== Periodic table: details sheet (phones & tablets) ===== */
@media (max-width: 640px) {
  .pt-legend {flex-wrap: nowrap; overflow-x: auto; margin: 0 -5%; padding: 2px 5% 8px; scrollbar-width: none; -webkit-overflow-scrolling: touch;}
  .pt-legend::-webkit-scrollbar {display: none;}
  .pt-legend-btn {flex-shrink: 0; padding: 8px 14px; font-size: 13px;}
  .pt-controls {gap: 12px; margin-bottom: 16px;}
  .pt-search input {padding: 13px 0; font-size: 16px;}
  .pt-page {padding-top: 22px;}
}
/* ===== Header: switch to the mobile menu earlier so tablets are not cramped ===== */
@media (max-width: 900px) {
  .mobile-menu-btn {display: block; width: 44px; height: 44px;}
  .nav-links {display: none; position: absolute; top: 100%; left: 0; width: 100%; background: var(--white); flex-direction: column; padding: 12px 0; box-shadow: 0 14px 24px rgba(45, 27, 45, 0.12); border-top: 1px solid var(--mid-lavender); z-index: 1000; gap: 0;}
  .nav-links li {width: 100%; text-align: center;}
  .nav-links li a {display: block; padding: 14px 20px;}
  .nav-links.active {display: flex;}
  .btn-demo {display: none;}
}
/* ===== Hero tool tiles: compact side-by-side on phones ===== */
@media (max-width: 560px) {
  .hero-tools {grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; margin-top: 22px;}
  .tool-chip {padding: 10px; gap: 9px;}
  .tool-chip-icon {width: 34px; height: 34px; border-radius: 9px;}
  .tool-chip-icon svg {width: 19px; height: 19px;}
  .tool-chip-text strong {font-size: 13px;}
  .tool-chip-text small {font-size: 11.5px;}
}
@media (max-width: 359px) {
  .hero-tools {grid-template-columns: 1fr;}
}
/* ===== Periodic table: fit the WHOLE table on tablets and phones ===== */
@media (max-width: 1399px) {
  .pt-grid {min-width: 0; --ch: clamp(34px, 5.2vw, 56px);}
}
@media (max-width: 640px) {
  .pt-zoom {display: inline-flex;}
  /* full-bleed table that fits the screen width */
  .pt-scroll:not(.pt-large) {margin: 0 calc(50% - 50vw); padding: 0 6px 6px; overflow-x: visible;}
  .pt-scroll:not(.pt-large) .pt-grid {--ch: calc((100vw - 12px - 14px - 36px) / 18 * 1.22); grid-template-columns: 14px repeat(18, minmax(0, 1fr)); grid-template-rows: 14px repeat(7, var(--ch)) 8px repeat(2, var(--ch)); gap: 2px; min-width: 0;}
  .pt-scroll:not(.pt-large) .pt-cell {padding: 0; justify-content: center; border-radius: 3px;}
  .pt-scroll:not(.pt-large) .pt-cell .n, .pt-scroll:not(.pt-large) .pt-cell .nm {display: none;}
  .pt-scroll:not(.pt-large) .pt-cell .s {font-size: 10.5px; letter-spacing: -0.2px;}
  .pt-scroll:not(.pt-large) .pt-cell.selected {box-shadow: 0 0 0 1.5px var(--c);}
  .pt-scroll:not(.pt-large) .pt-axis {font-size: 8px;}
  .pt-scroll:not(.pt-large) .pt-placeholder {font-size: 0; border-radius: 3px;}
  .pt-scroll:not(.pt-large) .pt-placeholder::after {content: '*'; font-size: 11px; font-weight: 700;}
  .pt-scroll:not(.pt-large) .pt-placeholder.cat-actinide::after {content: '**'; letter-spacing: -1px;}
  .pt-scroll:not(.pt-large) .pt-series-label {font-size: 8px; padding-right: 4px;}
  /* zoomed view: bigger cells, swipe sideways */
  .pt-scroll.pt-large {overflow-x: auto;}
  .pt-scroll.pt-large .pt-grid {min-width: 900px; --ch: 52px;}
  .pt-scroll.pt-large .pt-cell .nm {display: none;}
}
/* ===== Fallback for browsers without color-mix() (older iPhones) ===== */
.pt-placeholder {white-space: nowrap;}
@media (max-width: 1399px) {
  .pt-placeholder {font-size: 9px; letter-spacing: -0.2px;}
}
/* ================= Periodic table: details card (atom + uses) ================= */
.pt-gap {display: none; grid-column: 4 / 14; grid-row: 2 / 5; min-width: 0; flex-direction: column; justify-content: center; gap: 6px; padding: 0 8px;}
.pt-gap-title {font-family: 'Space Grotesk', sans-serif; font-size: 26px; font-weight: 700; color: var(--falsa-dark); line-height: 1.1;}
.pt-gap-sub {color: var(--text-light); font-size: 14px; margin-bottom: 8px;}
@media (min-width: 1400px) {
  .pt-gap {display: flex;}
  .pt-legend-home {display: none;}
}
/* popup: no extra frame inside the sheet */
/* phones: atom on top, details below */
/* laptops & tablets: a centered dialog instead of a bottom sheet */
/* fallback for browsers without color-mix() */
/* legend container must never grow wider than the screen */
.pt-legend-home {flex: 1 1 320px; min-width: 0; max-width: 100%;}
@media (max-width: 640px) {
  .pt-legend-home {flex-basis: 100%;}
}


/* ================= Periodic table: details panel (below the table) ================= */
.pt-panel { margin-top: 26px; scroll-margin-top: 90px; outline: none; }
.pt-panel[hidden] { display: none; }
.pt-info { position: relative; background: var(--light-bg); border: 1px solid var(--mid-lavender); border-radius: 22px; padding: 30px 18px 26px; text-align: center; display: flex; flex-direction: column; align-items: center; gap: 22px; box-shadow: 0 10px 30px rgba(123, 90, 166, 0.10); }
.pt-info-nav { position: absolute; top: 12px; left: 12px; right: 12px; display: flex; justify-content: space-between; pointer-events: none; }
.pt-nav-btn { pointer-events: auto; width: 44px; height: 44px; display: grid; place-items: center; border-radius: 50%; border: 2px solid var(--mid-lavender); background: var(--white); color: var(--falsa); cursor: pointer; transition: border-color .2s, transform .2s; }
.pt-nav-btn:hover:not(:disabled) { border-color: var(--zarda); transform: scale(1.05); }
.pt-nav-btn:disabled { opacity: .35; cursor: default; }
.pt-nav-btn:focus-visible, .pt-backtop:focus-visible { outline: 2px solid var(--falsa-dark); outline-offset: 2px; }

.pt-id { margin-top: 6px; }
.pt-id p, .pt-id h3 { margin: 0; }
.pt-id-num { font-size: 15px; color: var(--text-light); }
.pt-id-sym { font-family: 'Space Grotesk', sans-serif; font-size: 64px; font-weight: 700; line-height: 1.08; color: var(--falsa); }
.pt-id-name { font-size: 26px; font-weight: 700; color: var(--text-dark); margin: 2px 0 6px !important; }
.pt-id-mass { font-size: 16px; color: var(--text-light); }
.pt-id-mass small { font-size: 12px; }
.pt-id-cat { margin-top: 8px !important; font-size: 16px; font-weight: 700; color: var(--falsa); text-transform: capitalize; }

.pt-sec { max-width: 100%; }
.pt-sec h4 { display: inline-block; margin: 0 0 10px; padding-bottom: 3px; border-bottom: 3px solid var(--zarda); font-family: 'Space Grotesk', sans-serif; font-size: 15px; font-weight: 700; letter-spacing: .06em; text-transform: uppercase; color: var(--falsa); }
.pt-sec p { margin: 0; font-size: 17px; line-height: 1.55; color: var(--text-dark); }
.pt-cfgrow { display: flex; align-items: center; justify-content: center; flex-wrap: wrap; gap: 10px 14px; }
.pt-cfgrow h4 { margin: 0; }
.pt-cfgchip { display: inline-block; padding: 10px 16px; border-radius: 12px; background: var(--white); font-size: 19px; font-weight: 600; color: var(--text-dark); }
.pt-sec .pt-fullcfg { margin-top: 10px; font-size: 14px; color: var(--text-light); overflow-wrap: anywhere; }
.pt-fullcfg span { font-weight: 600; color: var(--falsa); }

.pt-diagram { width: min(300px, 78vw); margin: 4px auto 0; }
.pt-diagram svg { display: block; width: 100%; height: auto; }
.pt-diagram .shell { fill: none; stroke: rgba(123, 90, 166, 0.28); stroke-width: 1; }
.pt-diagram .e { fill: var(--zarda); }
.pt-diagram .nucleus { fill: var(--falsa); }
.pt-diagram .nuc-sym { fill: #fff; font-family: 'Space Grotesk', sans-serif; font-weight: 700; font-size: 14px; }
.pt-diagram .orb { transform-origin: 100px 100px; animation: orbSpin linear infinite; }
@keyframes orbSpin { to { transform: rotate(360deg); } }
@media (prefers-reduced-motion: reduce) { .pt-diagram .orb { animation: none; } }

.pt-usebox { display: flex; flex-direction: column; align-items: center; gap: 8px; min-width: min(260px, 100%); padding: 16px 24px 18px; background: var(--white); border: 1.5px dashed var(--mid-lavender); border-radius: 14px; }
.pt-usebox h4 { margin-bottom: 4px; }
.pt-sticker { font-size: 46px; line-height: 1; transform: rotate(-6deg); filter: drop-shadow(0 4px 6px rgba(45, 27, 45, 0.18)); }
.pt-usebox p { font-weight: 600; font-size: 17px; max-width: 320px; }

.pt-backtop { margin-top: 2px; background: var(--white); border: 2px solid var(--mid-lavender); color: var(--falsa); font: inherit; font-weight: 600; font-size: 14px; padding: 10px 20px; border-radius: 999px; cursor: pointer; transition: border-color .2s; }
.pt-backtop:hover { border-color: var(--zarda); }

/* bigger screens: two columns (identity + atom on the left, facts on the right) */
@media (min-width: 900px) {
  .pt-info { display: grid; grid-template-columns: minmax(280px, 340px) 1fr; column-gap: 48px; row-gap: 22px; align-items: center; text-align: left; padding: 40px 44px 32px; max-width: 1040px; margin: 0 auto; }
  .pt-id { grid-column: 1; grid-row: 1 / span 3; text-align: center; margin-top: 0; }
  .pt-s-atom { grid-column: 1; grid-row: 4 / span 4; text-align: center; }
  .pt-s-appear, .pt-s-pos, .pt-s-shell, .pt-s-cfg, .pt-s-facts, .pt-s-use { grid-column: 2; justify-self: start; text-align: left; }
  .pt-s-use { justify-self: start; }
  .pt-usebox { align-items: flex-start; text-align: left; }
  .pt-cfgrow { justify-content: flex-start; }
  .pt-backtop { grid-column: 1 / -1; justify-self: center; }
  .pt-id-sym { font-size: 84px; }
}
@media (max-width: 640px) {
  .pt-info { padding: 28px 14px 24px; }
  .pt-sec p { font-size: 16px; }
  .pt-sec h4 { font-size: 14px; }
}

/* fallback for browsers without color-mix() (older iPhones) */
@supports not (color: color-mix(in srgb, red 50%, blue)) {
  .pt-cell { background: #f6f0ff; border-color: var(--c); }
  .pt-cell.selected { background: #e9dcfb; }
  .pt-cell .s { color: var(--c); }
  .pt-placeholder { background: #f6f0ff; border-color: var(--c); color: var(--falsa-dark); }
  .pt-legend-btn[aria-pressed="true"] { background: #f6f0ff; }
}

@media (max-width: 600px) {.quote-text {font-size: 18px;}}