/* =============================================
   CalcLab — Design System & Global Styles
   ============================================= */

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #f8f9fc;
  --surface: #ffffff;
  --surface2: #f0f2f8;
  --border: #e2e5ef;
  --text: #1a1d2e;
  --text2: #5a5f7a;
  --text3: #9099b5;
  --accent: #4f46e5;
  --accent-hover: #4338ca;
  --accent-light: #eef2ff;
  --accent2: #06b6d4;
  --green: #10b981;
  --red: #ef4444;
  --amber: #f59e0b;
  --radius: 10px;
  --radius-lg: 14px;
  --shadow: 0 1px 4px rgba(0,0,0,0.07), 0 4px 16px rgba(0,0,0,0.04);
  --sidebar-w: 220px;
  --topbar-h: 56px;
  --transition: 0.2s ease;
  --font: 'Inter', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
}

[data-theme="dark"] {
  --bg: #0f1117;
  --surface: #1a1d2e;
  --surface2: #252840;
  --border: #2d3150;
  --text: #e8eaf5;
  --text2: #8b92b8;
  --text3: #525880;
  --accent: #6366f1;
  --accent-hover: #818cf8;
  --accent-light: rgba(99,102,241,0.12);
  --shadow: 0 1px 4px rgba(0,0,0,0.3), 0 4px 16px rgba(0,0,0,0.2);
}

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
}

/* =============================================
   App Shell
   ============================================= */
.app-shell {
  display: flex;
  min-height: 100vh;
}

/* =============================================
   Sidebar
   ============================================= */
.sidebar {
  width: var(--sidebar-w);
  background: var(--surface);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  position: fixed;
  top: 0; left: 0; bottom: 0;
  z-index: 100;
  transition: transform var(--transition);
  overflow-y: auto;
}

.sidebar-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 20px 18px 16px;
  border-bottom: 1px solid var(--border);
}

.brand-icon {
  width: 34px; height: 34px;
  background: var(--accent);
  color: white;
  border-radius: 9px;
  display: flex; align-items: center; justify-content: center;
  font-size: 18px; font-weight: 700;
  flex-shrink: 0;
}

.brand-name {
  font-size: 17px; font-weight: 700; letter-spacing: -0.3px;
  color: var(--text);
}

.sidebar-nav {
  padding: 12px 0;
  flex: 1;
}

.nav-section {
  font-size: 10px; font-weight: 600; letter-spacing: 0.8px;
  text-transform: uppercase; color: var(--text3);
  padding: 14px 18px 4px;
}

.nav-item {
  display: flex; align-items: center; gap: 10px;
  padding: 9px 18px;
  color: var(--text2);
  text-decoration: none;
  font-size: 14px; font-weight: 500;
  border-radius: 0;
  transition: background var(--transition), color var(--transition);
  cursor: pointer;
}

.nav-item:hover { background: var(--surface2); color: var(--text); }
.nav-item.active { background: var(--accent-light); color: var(--accent); font-weight: 600; }

.nav-icon { font-size: 16px; width: 20px; text-align: center; flex-shrink: 0; }

.sidebar-footer {
  padding: 12px 18px;
  border-top: 1px solid var(--border);
  display: flex; justify-content: flex-end;
}

.theme-toggle {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 6px 12px;
  cursor: pointer; font-size: 16px;
  transition: background var(--transition);
}
.theme-toggle:hover { background: var(--accent-light); }

/* =============================================
   Main Content
   ============================================= */
.main-content {
  margin-left: var(--sidebar-w);
  flex: 1;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.topbar {
  height: var(--topbar-h);
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  display: flex; align-items: center; gap: 16px;
  padding: 0 24px;
  position: sticky; top: 0; z-index: 50;
}

.menu-btn {
  background: none; border: none; cursor: pointer;
  font-size: 20px; color: var(--text2);
  display: none; padding: 4px;
}

.topbar-title {
  font-size: 16px; font-weight: 600; color: var(--text);
  flex: 1;
}

.btn-ghost {
  background: none; border: 1px solid var(--border);
  border-radius: 8px; padding: 6px 14px;
  font-size: 13px; color: var(--text2); cursor: pointer;
  transition: all var(--transition);
}
.btn-ghost:hover { background: var(--surface2); color: var(--text); }

/* =============================================
   Modules
   ============================================= */
.module {
  display: none;
  padding: 28px 28px;
  animation: fadeIn 0.25s ease;
  flex: 1;
}
.module.active { display: block; }

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

.module-header {
  margin-bottom: 28px;
}
.module-header h1 {
  font-size: 24px; font-weight: 700; letter-spacing: -0.4px;
  color: var(--text); margin-bottom: 4px;
}
.module-header p { color: var(--text2); font-size: 14px; }

.section-title {
  font-size: 12px; font-weight: 600; letter-spacing: 0.6px;
  text-transform: uppercase; color: var(--text3);
  margin: 28px 0 14px;
}

/* =============================================
   Dashboard
   ============================================= */
.dashboard-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px;
  margin-bottom: 8px;
}

.stat-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 20px 24px;
  box-shadow: var(--shadow);
}
.stat-value { font-size: 36px; font-weight: 700; color: var(--accent); }
.stat-label { font-size: 13px; color: var(--text2); margin-top: 2px; }

.quick-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px;
}

.quick-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 20px;
  cursor: pointer;
  transition: all var(--transition);
  box-shadow: var(--shadow);
}
.quick-card:hover {
  border-color: var(--accent);
  box-shadow: 0 4px 20px rgba(79,70,229,0.1);
  transform: translateY(-2px);
}
.quick-icon { font-size: 26px; margin-bottom: 10px; }
.quick-name { font-size: 14px; font-weight: 600; color: var(--text); }
.quick-desc { font-size: 12px; color: var(--text2); margin-top: 4px; }

.history-list { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); }
.history-item {
  display: flex; justify-content: space-between; align-items: center;
  padding: 10px 16px;
  border-bottom: 1px solid var(--border); font-size: 13px;
}
.history-item:last-child { border-bottom: none; }
.history-expr { color: var(--text2); font-family: var(--font-mono); }
.history-result { font-weight: 600; color: var(--accent); font-family: var(--font-mono); }
.history-empty { padding: 20px; text-align: center; color: var(--text3); font-size: 14px; }

.formulas-grid { display: flex; flex-wrap: wrap; gap: 10px; }
.formula-chip {
  background: var(--accent-light);
  color: var(--accent);
  border: 1px solid rgba(79,70,229,0.2);
  border-radius: 8px;
  padding: 7px 16px;
  font-size: 14px; font-family: var(--font-mono);
  cursor: pointer; font-weight: 600;
  transition: all var(--transition);
}
.formula-chip:hover { background: var(--accent); color: white; }

/* =============================================
   Calculator — Standard
   ============================================= */
.calc-layout {
  display: flex; gap: 24px; align-items: flex-start;
}

.calc-container {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 20px;
  width: 340px;
  flex-shrink: 0;
  box-shadow: var(--shadow);
}

.calc-display {
  background: var(--surface2);
  border-radius: var(--radius);
  padding: 16px 18px;
  margin-bottom: 12px;
  min-height: 80px;
  display: flex; flex-direction: column; justify-content: flex-end;
}
.calc-expression { font-size: 13px; color: var(--text3); font-family: var(--font-mono); min-height: 18px; }
.calc-value { font-size: 38px; font-weight: 300; color: var(--text); font-family: var(--font-mono); word-break: break-all; }

.calc-memory-bar {
  display: flex; gap: 6px; margin-bottom: 12px;
  align-items: center;
}
.mem-btn {
  flex: 1; padding: 6px 4px; font-size: 12px; font-weight: 600;
  background: var(--surface2); border: 1px solid var(--border);
  border-radius: 7px; cursor: pointer; color: var(--text2);
  transition: all var(--transition);
}
.mem-btn:hover { background: var(--accent-light); color: var(--accent); }
.mem-indicator { font-size: 11px; color: var(--accent); font-weight: 600; margin-left: 4px; }

.calc-grid {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 8px;
}

.calc-btn {
  padding: 0; height: 56px;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 18px; font-weight: 500;
  cursor: pointer; color: var(--text);
  transition: all 0.1s ease;
  display: flex; align-items: center; justify-content: center;
}
.calc-btn:hover { background: var(--border); }
.calc-btn:active { transform: scale(0.94); }
.calc-btn.btn-fn { background: var(--surface2); color: var(--text2); font-size: 14px; }
.calc-btn.btn-op { background: var(--accent-light); color: var(--accent); font-weight: 600; }
.calc-btn.btn-op:hover { background: var(--accent); color: white; }
.calc-btn.btn-eq { background: var(--accent); color: white; font-size: 20px; }
.calc-btn.btn-eq:hover { background: var(--accent-hover); }
.calc-btn.btn-clr { background: rgba(239,68,68,0.1); color: var(--red); }
.calc-btn.btn-wide { grid-column: span 2; }

.calc-history-panel {
  flex: 1; background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 16px; box-shadow: var(--shadow);
}
.panel-title { font-size: 13px; font-weight: 600; color: var(--text2); margin-bottom: 12px; }
.history-scroll { max-height: 420px; overflow-y: auto; }

/* =============================================
   Scientific Calculator
   ============================================= */
.sci-layout { display: flex; justify-content: center; }
.sci-container {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 20px;
  width: 520px; box-shadow: var(--shadow);
}

.angle-toggle { display: flex; gap: 6px; margin-bottom: 12px; }
.angle-btn {
  padding: 5px 16px; font-size: 12px; font-weight: 600;
  border: 1px solid var(--border); border-radius: 6px;
  cursor: pointer; background: var(--surface2); color: var(--text2);
  transition: all var(--transition);
}
.angle-btn.active { background: var(--accent); color: white; border-color: var(--accent); }

.sci-grid {
  display: grid; grid-template-columns: repeat(6, 1fr); gap: 6px;
}
.sci-grid .calc-btn { height: 46px; font-size: 13px; }

/* =============================================
   Equation Module
   ============================================= */
.eq-layout { display: flex; flex-direction: column; gap: 24px; max-width: 760px; }

.eq-presets { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 12px; align-items: center; }
.preset-label { font-size: 12px; color: var(--text3); font-weight: 600; }
.preset-btn {
  background: var(--surface2); border: 1px solid var(--border);
  border-radius: 7px; padding: 5px 13px; font-size: 13px; font-family: var(--font-mono);
  cursor: pointer; color: var(--text2); font-weight: 500;
  transition: all var(--transition);
}
.preset-btn:hover { background: var(--accent-light); color: var(--accent); border-color: rgba(99,102,241,0.3); }

.eq-field-wrap { display: flex; gap: 10px; }
.eq-field {
  flex: 1; padding: 12px 16px;
  background: var(--surface); border: 1.5px solid var(--border);
  border-radius: var(--radius); font-size: 18px; font-family: var(--font-mono);
  color: var(--text); transition: border-color var(--transition);
  outline: none;
}
.eq-field:focus { border-color: var(--accent); }

.eq-btn {
  padding: 12px 24px; background: var(--accent); color: white;
  border: none; border-radius: var(--radius); font-size: 14px; font-weight: 600;
  cursor: pointer; transition: background var(--transition); white-space: nowrap;
}
.eq-btn:hover { background: var(--accent-hover); }

.eq-rendered {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 16px 20px;
  font-size: 20px; min-height: 56px;
  display: flex; align-items: center;
}

.eq-solver {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 24px; box-shadow: var(--shadow);
}
.eq-vars-title { font-size: 13px; font-weight: 600; color: var(--text2); margin-bottom: 16px; }
.eq-var-row { display: flex; align-items: center; gap: 14px; margin-bottom: 14px; }
.eq-var-label { font-family: var(--font-mono); font-size: 15px; font-weight: 600; color: var(--accent); min-width: 40px; }
.eq-var-name { font-size: 13px; color: var(--text2); min-width: 120px; }
.eq-var-input {
  flex: 1; padding: 8px 12px;
  background: var(--surface2); border: 1px solid var(--border);
  border-radius: 8px; font-size: 15px; color: var(--text);
  font-family: var(--font-mono); outline: none;
  transition: border-color var(--transition);
}
.eq-var-input:focus { border-color: var(--accent); }
.eq-result-block {
  margin-top: 20px; padding: 16px 20px;
  background: var(--accent-light); border: 1px solid rgba(99,102,241,0.2);
  border-radius: var(--radius);
}
.eq-result-label { font-size: 12px; color: var(--accent); font-weight: 600; margin-bottom: 6px; }
.eq-result-val { font-size: 28px; font-weight: 700; color: var(--accent); font-family: var(--font-mono); }
.eq-result-unit { font-size: 14px; color: var(--text2); margin-top: 4px; }

/* =============================================
   Triangle Module
   ============================================= */
.triangle-layout { display: flex; gap: 24px; }
.triangle-canvas-wrap {
  position: relative;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); box-shadow: var(--shadow); overflow: hidden;
}
#triangle-canvas { display: block; cursor: crosshair; }
.canvas-controls {
  position: absolute; bottom: 12px; left: 12px;
  display: flex; gap: 6px;
}
.ctrl-btn {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 7px; padding: 5px 12px; font-size: 12px;
  cursor: pointer; color: var(--text2); font-weight: 500;
  transition: all var(--transition);
}
.ctrl-btn:hover, .ctrl-btn.active { background: var(--accent-light); color: var(--accent); border-color: rgba(99,102,241,0.3); }

.triangle-info { flex: 1; display: flex; flex-direction: column; gap: 16px; }
.tri-section {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 16px 20px; box-shadow: var(--shadow);
}
.tri-section-title { font-size: 11px; font-weight: 700; letter-spacing: 0.7px; text-transform: uppercase; color: var(--text3); margin-bottom: 10px; }
.tri-row { display: flex; justify-content: space-between; align-items: center; padding: 5px 0; border-bottom: 1px solid var(--border); }
.tri-row:last-child { border-bottom: none; }
.tri-label { font-size: 13px; color: var(--text2); }
.tri-val { font-size: 13px; font-weight: 600; color: var(--text); font-family: var(--font-mono); }

/* =============================================
   Gravity / Projectile Modules
   ============================================= */
.gravity-layout, .proj-layout { display: flex; gap: 24px; }
.gravity-params, .proj-params {
  width: 260px; flex-shrink: 0;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 20px; box-shadow: var(--shadow);
}
.param-group { margin-bottom: 16px; }
.param-group label { font-size: 12px; font-weight: 600; color: var(--text2); display: block; margin-bottom: 6px; }
.param-group input[type="range"] { width: 100%; accent-color: var(--accent); }
.param-val { font-size: 14px; font-weight: 700; color: var(--accent); font-family: var(--font-mono); display: block; text-align: right; }

.sim-btn {
  width: 100%; padding: 11px; background: var(--accent); color: white;
  border: none; border-radius: var(--radius); font-size: 14px; font-weight: 600;
  cursor: pointer; transition: background var(--transition); margin-top: 4px;
}
.sim-btn:hover { background: var(--accent-hover); }
.sim-btn-reset { background: var(--surface2); color: var(--text2); border: 1px solid var(--border); margin-top: 8px; }
.sim-btn-reset:hover { background: var(--border); }

.gravity-vis {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); overflow: hidden; box-shadow: var(--shadow);
  flex-shrink: 0;
}
#gravity-canvas { display: block; }

.gravity-results, .proj-results-area { flex: 1; }
.gravity-results {
  display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; align-content: start;
}
.result-card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 14px 16px; box-shadow: var(--shadow);
}
.result-val { font-size: 22px; font-weight: 700; color: var(--accent); font-family: var(--font-mono); }
.result-lbl { font-size: 11px; color: var(--text2); margin-top: 2px; }

.proj-results-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px;
}

/* =============================================
   Graphs Module
   ============================================= */
.graphs-layout {
  display: flex; gap: 24px;
}
.graph-controls {
  width: 240px; flex-shrink: 0;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 18px; box-shadow: var(--shadow);
}
.graph-fn-list { margin-bottom: 12px; }
.graph-fn-row {
  display: flex; align-items: center; gap: 6px; margin-bottom: 8px;
}
.graph-fn-input {
  flex: 1; padding: 7px 10px;
  background: var(--surface2); border: 1px solid var(--border);
  border-radius: 7px; font-size: 13px; color: var(--text);
  font-family: var(--font-mono); outline: none;
}
.graph-fn-input:focus { border-color: var(--accent); }
.fn-color { width: 16px; height: 16px; border-radius: 4px; flex-shrink: 0; }
.fn-remove {
  background: none; border: none; cursor: pointer; font-size: 16px;
  color: var(--text3); padding: 0 2px; line-height: 1;
}
.fn-remove:hover { color: var(--red); }
.graph-add-btn {
  width: 100%; padding: 8px; background: none; border: 1px dashed var(--border);
  border-radius: 8px; font-size: 13px; color: var(--text2); cursor: pointer;
  transition: all var(--transition); margin-bottom: 14px;
}
.graph-add-btn:hover { border-color: var(--accent); color: var(--accent); }
.graph-range {
  display: flex; flex-direction: column; gap: 8px; margin-bottom: 12px;
}
.graph-range label { font-size: 12px; color: var(--text2); font-weight: 600; }
.graph-range input {
  padding: 6px 10px; background: var(--surface2); border: 1px solid var(--border);
  border-radius: 7px; color: var(--text); font-size: 13px; outline: none;
  width: 100%; margin-top: 4px;
}
.fn-presets { margin-top: 14px; display: flex; flex-wrap: wrap; gap: 6px; }

/* =============================================
   Matrix Module
   ============================================= */
.matrix-layout { display: flex; flex-direction: column; gap: 24px; max-width: 800px; }
.matrix-setup {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 24px; box-shadow: var(--shadow);
}
.matrix-size { margin-bottom: 20px; }
.matrix-size select {
  padding: 7px 12px; background: var(--surface2); border: 1px solid var(--border);
  border-radius: 8px; color: var(--text); font-size: 14px; outline: none;
  margin-left: 8px;
}
.matrices-row { display: flex; gap: 40px; margin-bottom: 24px; }
.matrix-block {}
.matrix-label { font-size: 13px; font-weight: 700; color: var(--text2); margin-bottom: 10px; font-family: var(--font-mono); font-style: italic; }
.matrix-grid { display: grid; gap: 6px; }
.mat-cell {
  width: 64px; height: 40px; text-align: center;
  background: var(--surface2); border: 1px solid var(--border);
  border-radius: 7px; font-size: 14px; color: var(--text);
  font-family: var(--font-mono); outline: none;
  transition: border-color var(--transition);
}
.mat-cell:focus { border-color: var(--accent); }
.matrix-ops { display: flex; flex-wrap: wrap; gap: 8px; }
.mat-op-btn {
  padding: 8px 18px; background: var(--surface2);
  border: 1px solid var(--border); border-radius: 8px;
  font-size: 13px; font-family: var(--font-mono); font-weight: 600;
  cursor: pointer; color: var(--text2); transition: all var(--transition);
}
.mat-op-btn:hover { background: var(--accent-light); color: var(--accent); border-color: rgba(99,102,241,0.3); }
.matrix-result-area {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 24px; box-shadow: var(--shadow); min-height: 80px;
}
.result-title { font-size: 13px; font-weight: 600; color: var(--text2); margin-bottom: 14px; }
.matrix-result { display: grid; gap: 6px; }
.mat-result-cell {
  width: 80px; height: 40px; display: flex; align-items: center; justify-content: center;
  background: var(--accent-light); border: 1px solid rgba(99,102,241,0.2);
  border-radius: 7px; font-size: 14px; color: var(--accent);
  font-family: var(--font-mono); font-weight: 600;
}
.matrix-scalar { font-size: 28px; font-weight: 700; color: var(--accent); font-family: var(--font-mono); }

/* =============================================
   Converter Module
   ============================================= */
.converter-tabs { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 24px; }
.conv-tab {
  padding: 8px 18px; background: var(--surface2);
  border: 1px solid var(--border); border-radius: 8px;
  font-size: 13px; font-weight: 500; cursor: pointer; color: var(--text2);
  transition: all var(--transition);
}
.conv-tab.active { background: var(--accent); color: white; border-color: var(--accent); }
.conv-tab:hover:not(.active) { background: var(--accent-light); color: var(--accent); }

.converter-body {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 28px; box-shadow: var(--shadow); max-width: 560px;
}
.conv-group { margin-bottom: 18px; position: relative; }
.conv-group label { font-size: 12px; font-weight: 600; color: var(--text2); display: block; margin-bottom: 6px; }
.conv-input-wrap { display: flex; gap: 8px; }
.conv-input {
  flex: 1; padding: 10px 14px;
  background: var(--surface2); border: 1.5px solid var(--border);
  border-radius: var(--radius); font-size: 16px; color: var(--text);
  font-family: var(--font-mono); outline: none; transition: border-color var(--transition);
}
.conv-input:focus { border-color: var(--accent); }
.conv-unit {
  padding: 10px 14px; background: var(--accent-light);
  border: 1px solid rgba(99,102,241,0.2); border-radius: var(--radius);
  font-size: 14px; font-weight: 600; color: var(--accent);
  display: flex; align-items: center; min-width: 60px; justify-content: center;
}
.conv-divider { text-align: center; font-size: 20px; color: var(--text3); margin: 6px 0; }

/* =============================================
   Scrollbar
   ============================================= */
::-webkit-scrollbar { width: 5px; height: 5px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 99px; }
::-webkit-scrollbar-thumb:hover { background: var(--text3); }

/* =============================================
   Responsive
   ============================================= */
@media (max-width: 900px) {
  .sidebar { transform: translateX(-100%); }
  .sidebar.open { transform: translateX(0); }
  .main-content { margin-left: 0; }
  .menu-btn { display: block; }
  .dashboard-grid, .quick-grid { grid-template-columns: repeat(2, 1fr); }
  .calc-layout { flex-direction: column; }
  .triangle-layout { flex-direction: column; }
  .gravity-layout, .proj-layout { flex-direction: column; }
  .gravity-results { grid-template-columns: repeat(2, 1fr); }
  .graphs-layout { flex-direction: column; }
  .graph-controls { width: 100%; }
  .sci-grid { grid-template-columns: repeat(4, 1fr); }
  .matrices-row { flex-direction: column; gap: 20px; }
}

@media (max-width: 600px) {
  .module { padding: 16px; }
  .dashboard-grid { grid-template-columns: 1fr; }
  .quick-grid { grid-template-columns: repeat(2, 1fr); }
  .proj-results-grid { grid-template-columns: repeat(2, 1fr); }
  .calc-container { width: 100%; }
  .sci-container { width: 100%; }
}