/* -------------------------
   Core / reset
   ------------------------- */
:root {
  --navy: #2c3e50;
  --softgray: #ecf0f1;
  --teal: #1abc9c;
  --gold: #f1c40f;
  --slate: #7f8c8d;
  --coral: #e74c3c;
  --white: #ffffff;
  --gray-100: #f7fafc;
  --gray-200: #edf2f7;
  --gray-300: #e2e8f0;
  --max-width: 1200px;
  --container-pad: 16px;
  --radius: 10px;
  --shadow-sm: 0 6px 18px rgba(0, 0, 0, 0.06);
  --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.06);
}
* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
}
/* Page base */
body {
  margin: 0;
  font-family: "Montserrat", system-ui, -apple-system, "Segoe UI", Roboto,
    "Helvetica Neue", Arial;
  color: var(--navy);
  background: linear-gradient(135deg, #ecf0f1 0%, #d6dbdf 100%);
  padding: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
li {
  line-height: 2;
}
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  gap: 18px;
  padding: 18px;
}
/* Utility */
.hidden { display: none !important; }

.header h1 {
  margin: 0;
  font-size: 2rem;
  font-weight: 600;
  font-family: 'Montserrat', sans-serif;
}
.header-left{
  justify-self: start;
}

.page-header {
    text-align: center;
    color: var(--navy);
    padding: 1rem;
    position: relative;
}

.header-grid{
  display: grid;
  grid-template-columns: 1fr auto 1fr; 
  align-items: center;
  gap: 12px;
  padding: 8px 0;
}
.page-title{
  margin: 0;
  justify-self: center;   /* ensures exact centering of the title cell */
  font-size: clamp(1.25rem, 3vw, 2rem);
  font-weight: 700;
  font-family: 'Montserrat', sans-serif;
}
.header-actions{
  justify-self: end;
}

/* mobile: stack nicely */
@media (max-width: 767px){
  .header-grid{
    grid-template-columns: 1fr; /* stack everything */
    grid-auto-flow: row;
    text-align: left;
  }
  .page-title{ justify-self: start; }
  .header-actions{ justify-self: start; width:100%; margin-top:8px; }
  
}
.cols {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

/* Buttons positioned top-left and top-right */
.btn {
    display: inline-block;
    padding: 0.5rem 1rem;
    border-radius: 0.375rem;
    font-weight: 500;
    text-decoration: none;
    text-align: center;
    transition: all 0.2s;
    cursor: pointer;
    border: 1px solid transparent;
    width: auto;
    font-size: 16px;
    font-weight: 600;
    padding: 12px 24px;
}
.btn:active {
  transform: translateY(1px);
}

/* button variants */
.teal-btn {
  background: rgba(26, 188, 156, 0.9);
  color: var(--white);
}
.teal-btn:hover {
  background: rgba(26, 188, 156, 0.8);
  transform: translateY(-10%);
  opacity: 0.98;
}

.gold-btn {
  background: rgba(241, 196, 15, 0.9);
  color: var(--navy);
}
.gold-btn:hover {
  background: rgba(241, 196, 15, 0.8);
  transform: translateY(-10%);
  opacity: 0.98;
}

.navy-btn {
  background: rgba(44, 62, 80, 0.9);
  color: var(--white);
}
.navy-btn:hover {
  background: rgba(44, 62, 80, 0.8);
  transform: translateY(-10%);
  opacity: 0.98;
}
.coral-btn {
  background-color: rgba(231, 76, 60, 0.8);
  color: white;
}

.coral-btn:hover {
  background-color: rgba(231, 76, 60, 0.7);
  transform: translateY(-10%);
  opacity: 0.98;
}


/* -------------------------
   Main wrapper and layout
   ------------------------- */

.main {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

/* top section layout mirrors flex-col on small, row on lg */
.top-section {
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin-bottom: 16px;
}

/* On larger screens place side-by-side (match lg:flex-row) */
@media (min-width: 1024px) {
  .top-section { flex-direction: row; align-items: flex-start; }
}

/* Simulation column expands */
.sim-column { flex: 1; }

/* Controls column fixed width similar to lg:w-96 (24rem ~ 384px) */
.controls-column { max-width: 384px; width: 100%; }

/* -------------------------
   Simulation container
   ------------------------- */
.simulation-container {
  background: #ffffff;
  border-radius: 12px;
  box-shadow: 0 10px 30px rgba(44,62,80,0.09);
  padding: 16px;
  height: clamp(400px, 60vw, 600px);
  position: relative;
  overflow: hidden;
}


.sim-inner {
  height: 100%;
  display: flex;
  justify-content: center; /* keep horizontal centering */
  align-items: flex-start; /* <-- align children to top of the sim area */
  padding-top: 10px;      
}


.material-setup {
  
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-start; 
  padding-top: 18px;           
  width: 66%;
  position: relative;
  z-index: 2;
}

.material-label {
  text-align: center;
  font-weight: 700;
 
  margin-bottom: 8px;
  background: rgba(26,188,156,0.2); 
  padding: 10px 24px;
  border-radius: 999px;
  font-size: 1.125rem;
  color: #2C3E50;
}

/* stand, hook, small helpers (keep original look) */
.stand {
  margin: 0 0 8px 0; /* no extra top margin */
  width: 16rem;
  height: 1rem;
  background-color: #7F8C8D;
}
.hook { width: 2rem; height: 1rem; background-color: #7F8C8D; border-radius: 50% 50% 0 0; margin-top: -8px; }
.w-64 { width: 16rem; }
.h-4 { height: 1rem; }
.mb-2 { margin-bottom: 0.5rem; }
.w-8 { width: 2rem; }
.h-4 { height: 1rem; }
.negative-mt-2 { margin-top: -0.5rem; }

/* spring container / svg */
.spring-container {
  width: 56px;
  transition: height 0.5s ease;
  display: flex;
  justify-content: center;
  z-index: 2;
}

.spring-svg { width: 100%; height: 100%; display: block; }
#spring-path {
  stroke: #2C3E50;
  stroke-width: 1.5;
  fill: none;
  vector-effect: non-scaling-stroke;
  transition: d .5s ease;
}

/* rubber band */
.rubber-band {
  background-color: #E74C3C;
  border-radius: 4px;
  transition: height 0.5s ease;
  width: 8px;
}

/* mass and connector */
.mass-hook {
  position: relative;
  z-index: 10;
  background-color: #7F8C8D;
  transition: all 0.3s ease;
  margin-bottom: -1px;
  width: 1.5rem;
  height: 0.5rem;
  margin-left: auto;
  margin-right: auto;
  border-radius: 0 0 8px 8px;
}

.mass-connector {
  width: 2px;
  height: 40px;
  background-color: #2C3E50;
  margin: 6px auto 0;
  border-radius: 2px 2px 0 0;
}

.mass-stack { transition: all 0.3s ease; text-align: center; }
#mass-stack {
  position: absolute;
  top: calc(40px);    
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
 
  z-index: 20;
  pointer-events: none;     
}
.base-mass {
  background-color: #2C3E50;
  border-radius: 5px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}
.base-mass-small { width: 4rem; height: 1rem; }

/* additional masses look */
.additional-mass {
  width: 64px;
  height: 16px;
  background-color: #3a5169;
  margin: 1px 0;
  border-radius: 5px;
}

/* -------------------------
   Ruler
   ------------------------- */
.ruler {
  position: absolute;
  left: 20px;
  top: 40px;
  width: 50px;
  height: 370px;
  background: #f8f1e0;
  border: 1px solid #d4c9a8;
  box-shadow: 1px 1px 4px rgba(0,0,0,0.2);
  cursor: move;
  z-index: 1;
  border-radius: 2px;
  touch-action: none;
}

/* Ruler ticks — put this at the end of your CSS to ensure it wins */
#ruler-scale { position: relative; height: 100%; border-left: 2px solid #333; }

/* base tick */
#ruler-scale .cm-mark {
  position: absolute;
  left: 0;
  width: 18px;            /* major tick length */
  height: 1px;
  background: #333;
  top: 0;                 /* JS will change top per-tick */
  pointer-events: none;
}

/* medium (5mm) */
#ruler-scale .cm-mark.medium {
  width: 12px;
  background: #666;
}

/* minor (1mm) */
#ruler-scale .cm-mark.minor {
  width: 8px;
  background: #999;
}

/* optional: number labels (if you add .cm-number elements) */
#ruler-scale .cm-number {
  position: absolute;
  left: 22px;
  font-family: Arial, sans-serif;
  font-size: 12px;
  color: #333;
  transform: translateY(-50%);
  pointer-events: none;
}


#ruler-handle, .ruler-handle {
  position: absolute;
  left: -15px;
  top: 50%;
  width: 30px;
  height: 30px;
  background: #d4c9a8;
  opacity: 0.7;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  cursor: move;
  user-select: none;
  box-shadow: 1px 1px 3px rgba(0,0,0,0.2);
  transform: translateY(-50%);
}

/* -------------------------
   Controls panel
   ------------------------- */
.controls-panel {
  background: #2C3E50; /* navy */
  color: #fff;
  border-radius: 12px;
  box-shadow: 0 10px 30px rgba(44,62,80,0.09);
  padding: 16px;
  min-height: 600px;
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
}

.controls-title {
  font-size: 1.125rem;
  font-weight: 700;
  margin: 0 0 12px 0;
  text-align: center;
  color: #fff;
}

/* control blocks */
.control-block { margin-bottom: 16px; }
.control-heading { font-weight: 600; margin: 0 0 8px 0; color: #fff; }

/* material selection row */
.material-selection-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  background: rgba(255,255,255,0.10);
  padding: 12px;
  border-radius: 8px;
}

.label-text { font-weight: 500; color: #fff; }

/* toggle switch (same as your CSS) */
.material-toggle {
  position: relative;
  display: inline-block;
  width: 60px;
  height: 34px;
}
.material-toggle input { opacity: 0; width: 0; height: 0; }
.slider {
  position: absolute;
  cursor: pointer;
  top: 0; left: 0; right: 0; bottom: 0;
  background-color: #7F8C8D;
  transition: .4s;
  border-radius: 34px;
}
.slider:before {
  position: absolute;
  content: "";
  height: 26px; width: 26px; left: 4px; bottom: 4px;
  background-color: white; transition: .4s; border-radius: 50%;
}
.material-toggle input:checked + .slider { background-color: #E74C3C; }
.material-toggle input:checked + .slider:before { transform: translateX(26px); }

/* -------------------------
   Spring options grid
   ------------------------- */
.spring-options-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
}

.spring-option {
  background: rgba(26,188,156,1); /* will be overridden for opacity variants below */
  padding: 8px;
  text-align: center;
  border-radius: 8px;
  cursor: pointer;
  color: #fff;
  transition: transform .2s ease, box-shadow .2s ease;
}

/* to mimic bg-teal bg-opacity variants, we set opacity where used:
   first option (selected) solid teal, second medium opacity, third more transparent */
.spring-option:nth-child(1) { background: #1ABC9C; }
.spring-option:nth-child(2) { background: rgba(26,188,156,0.8); }
.spring-option:nth-child(3) { background: rgba(26,188,156,0.6); }

.spring-option .spring-option-sub { font-size: 0.75rem; opacity: 0.95; color: white; }

.spring-option.selected {
  transform: translateY(-4px);
  box-shadow: 0 12px 28px rgba(0,0,0,0.12);
}

/* -------------------------
   Mass controls
   ------------------------- */
.mass-controls-inner {
  background: rgba(255,255,255,0.10);
  border-radius: 8px;
  padding: 12px;
}

.mass-display { text-align: center; font-weight: 700; font-size: 1rem; margin-bottom: 8px; color: #fff; }

.mass-buttons-row {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}




.remove-mass-btn { background: #E74C3C; color: #fff; width: 128px; justify-content: center; }
.add-mass-btn { background: #F1C40F; color: #2C3E50; width: 128px; justify-content: center; }

/* small icon sizing */
.icon { width: 18px; height: 18px; }

/* record block */
.record-inner {
  display: flex;
  gap: 8px;
  align-items: center;
  background: rgba(255,255,255,0.10);
  padding: 12px;
  border-radius: 8px;
}

.record-left { flex: 1; }
.block-label { display: block; margin-bottom: 6px; color: #fff; font-size: 0.9rem; }
.extension-input { padding: 8px; border-radius: 8px; border: none; width: 100%; max-width: 160px; }

/* record button styled similar to toggle */
.record-btn { background: #1ABC9C; color: #fff; }

/* reset button across full width */
.reset-btn {
  background: #E74C3C;
  color: #fff;
  padding: 10px;
  border-radius: 8px;
  width: 100%;
  margin-top: 12px;
}

/* -------------------------
   Instructions section
   ------------------------- */
.instructions-wrapper {
  background: #2C3E50;
  color: #fff;
  border-radius: 12px;
  padding: 16px 24px;
  box-shadow: 0 10px 30px rgba(44,62,80,0.09);
}

.instructions-title {
  text-align: center;
  margin: 0 0 12px 0;
  font-weight: 700;
  font-size: 1.125rem;
  color: #fff;
}

.instructions-aim {
  margin: 0 0 12px 0;
  line-height: 1.6;
}

.instructions-list {
  margin: 0;
  padding-left: 20px;
  line-height: 2;
}

/* -------------------------
   Results section
   ------------------------- */
.results-wrapper {
  background: #2C3E50;
  color: #fff;
  border-radius: 12px;
  padding: 16px;
  box-shadow: 0 10px 30px rgba(44,62,80,0.09);
}

.results-title { text-align: center; margin: 0 0 12px 0; font-weight: 700; font-size: 1.125rem; color: #fff; }

.results-table-wrap { overflow-x: auto; }

.results-table {
  width: 100%;
  border-collapse: collapse;
  min-width: 640px;
}

.results-table thead th {
  text-align: left;
  padding: 10px 12px;
  font-weight: 700;
  border-bottom: 1px solid rgba(255,255,255,0.30);
  color: #fff;
}

.results-table tbody td {
  padding: 10px 12px;
  text-align: center;
  border-bottom: 1px dashed rgba(255,255,255,0.04);
  color: #fff;
}

/* actions column width like w-24 */
.actions-col { width: 6rem; }

.results-table tbody tr:nth-child(even) { background-color: rgba(255,255,255,0.03); }

/* no results text */
.no-results-text {
  text-align: center;
  padding: 12px;
  color: rgba(255,255,255,0.85);
  font-style: italic;
}

/* -------------------------
   Small responsive tweaks to match sm:px and etc
   ------------------------- */
@media (max-width: 1024px) {
  .controls-column { width: 100%; }
  .controls-panel { min-height: auto; }
  .top-section { gap: 12px; }
}

@media (max-width: 640px) {
  .title-row { padding: 0 16px; }
  .page-title { font-size: 1.25rem; }
  .help-button, .quiz-button { width: 120px; top: -12px; }
}
/* Table row / cell utilities (replaces Tailwind utilities used in JS) */
.table-row.row-bordered {
  border-bottom: 1px solid rgba(255, 255, 255, 0.10); /* border-white + 10% opacity */
}

/* cell padding & alignment that matches py-2 px-4 text-centre etc */
.cell {
  padding: 8px 12px;            /* roughly equivalent to py-2 px-4 */
  vertical-align: middle;
  color: inherit;               /* inherit text color from table */
  font-size: 0.95rem;
  box-sizing: border-box;
}

.cell-left {
  text-align: left;
}

.cell-center {
  text-align: center;
}


.small-btn {
  padding: 6px 10px;
  font-size: 0.9rem;
}

/* specific delete button extras (optional) */
.delete-btn {
  /* keep a consistent width so table stays tidy (optional) */
  min-width: 72px;
  padding-left: 10px;
  padding-right: 10px;
}

/* Ensure table cells remain readable on narrow screens */
@media (max-width: 480px) {
  .cell { padding: 6px 8px; }
  .small-btn { padding: 6px 8px; font-size: 0.85rem; min-width: 68px; }
}