/* physics-lesson.css — shared styles for all AQA Physics lesson pages */
@import url('https://fonts.googleapis.com/css2?family=Fredoka+One&family=Quicksand:wght@400;500;600;700&display=swap');

:root {
  --pink:#d1498b; --pink-dark:#a8366d; --pink-light:#fff0f8;
  --blue:#1e88e5; --blue-dark:#1565c0; --blue-light:#e3f2fd;
  --green:#43aa8b; --orange:#f4845f; --yellow:#f9c74f; --purple:#7b5ea7;
  --bg:#fff9fc; --card:#fff; --text:#2d2d2d; --text-light:#666;
  --border:#f0d0e0; --radius:14px; --shadow:0 4px 20px rgba(209,73,139,0.1);
}
*{box-sizing:border-box;margin:0;padding:0;}
body{font-family:'Quicksand',sans-serif;background:var(--bg);color:var(--text);min-height:100vh;}
h1,h2,h3,.tab-btn,.nav-tab,.nav-brand{font-family:'Fredoka One',cursive;}

/* Header */
header{background:linear-gradient(135deg,var(--pink),var(--pink-dark));color:#fff;padding:0 24px;position:sticky;top:0;z-index:100;box-shadow:0 2px 12px rgba(0,0,0,0.15);}
.header-inner,.nav-inner{max-width:1100px;margin:0 auto;display:flex;align-items:center;gap:16px;height:60px;}
.nav-brand,.logo{font-size:1.3rem;color:#fff;text-decoration:none;}
.nav-brand span,.logo span{color:var(--yellow);}
.header-title{font-size:1rem;opacity:.9;margin-left:auto;}
.spec-badge,.breadcrumb{font-size:0.75rem;opacity:.85;background:rgba(255,255,255,.2);padding:3px 10px;border-radius:20px;white-space:nowrap;margin-left:auto;}

/* Tabs */
.tabs-wrap,.nav-tabs-wrap{background:#fff;border-bottom:2px solid var(--border);position:sticky;top:60px;z-index:99;overflow-x:auto;}
.tabs,.nav-tabs{display:flex;max-width:1100px;margin:0 auto;gap:2px;padding:0 8px;}
.tab-btn,.nav-tab{padding:11px 15px;border:none;background:none;cursor:pointer;font-size:0.85rem;color:var(--text-light);border-bottom:3px solid transparent;transition:all .2s;white-space:nowrap;font-family:'Fredoka One',cursive;}
.tab-btn:hover,.nav-tab:hover{color:var(--pink);}
.tab-btn.active,.nav-tab.active{color:var(--pink);border-bottom-color:var(--pink);}

/* Sections */
.section{display:none;padding:28px 20px;max-width:1100px;margin:0 auto;}
.section.active{display:block;}

/* Cards */
.card{background:var(--card);border-radius:var(--radius);padding:22px;margin-bottom:18px;box-shadow:var(--shadow);}
.card-pink{border-left:5px solid var(--pink);}
.card-blue{border-left:5px solid var(--blue);}
.card-green{border-left:5px solid var(--green);}
.card-orange{border-left:5px solid var(--orange);}
.card-purple{border-left:5px solid var(--purple);}

/* Key elements */
.equation-box{background:linear-gradient(135deg,#fff0f8,#e8f4ff);border:2px solid var(--pink);border-radius:10px;padding:14px 20px;font-size:1.1rem;font-family:'Fredoka One',cursive;text-align:center;color:var(--pink-dark);margin:12px 0;}
.key-def{background:var(--blue-light);border-left:4px solid var(--blue);border-radius:0 8px 8px 0;padding:12px 16px;font-size:.9rem;line-height:1.6;margin:10px 0;}
.key-point{background:var(--pink-light);border-left:4px solid var(--pink);border-radius:0 8px 8px 0;padding:12px 16px;font-size:.9rem;line-height:1.6;margin:10px 0;}
.warning-box{background:#fff8e1;border-left:4px solid var(--yellow);border-radius:0 8px 8px 0;padding:12px 16px;font-size:.9rem;margin:10px 0;}

/* Hero (home section) */
.hero{background:linear-gradient(135deg,var(--pink),var(--blue-dark));color:#fff;border-radius:var(--radius);padding:36px;margin-bottom:24px;text-align:center;}
.hero h1{font-size:2rem;margin-bottom:8px;}
.hero p{opacity:.9;font-size:1rem;line-height:1.6;}
.spec-tag{display:inline-block;background:rgba(255,255,255,.25);padding:4px 14px;border-radius:20px;font-size:.82rem;margin-top:10px;}

/* Objectives list */
.objectives-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:12px;margin-top:16px;}
.obj-item{background:var(--card);border-radius:10px;padding:14px;border:1px solid var(--border);display:flex;gap:10px;align-items:flex-start;font-size:.88rem;line-height:1.5;}
.obj-icon{font-size:1.1rem;flex-shrink:0;}

/* Tables */
.info-table{width:100%;border-collapse:collapse;font-size:.88rem;margin:12px 0;}
.info-table th{background:var(--pink);color:#fff;padding:10px 14px;text-align:left;}
.info-table td{padding:9px 14px;border-bottom:1px solid #f0e0e8;}
.info-table tr:nth-child(even) td{background:#fdf5f9;}

/* Examples */
.example-block{background:var(--card);border-radius:var(--radius);padding:20px;margin-bottom:16px;border:1px solid var(--border);}
.example-q{background:var(--blue-light);border-radius:8px;padding:12px 16px;margin-bottom:12px;font-weight:600;font-size:.93rem;}
.step{display:flex;gap:12px;margin:10px 0;font-size:.9rem;line-height:1.6;align-items:flex-start;}
.step-num{background:var(--pink);color:#fff;border-radius:50%;width:24px;height:24px;display:flex;align-items:center;justify-content:center;font-family:'Fredoka One',cursive;font-size:.85rem;flex-shrink:0;}
.answer-box{background:linear-gradient(135deg,#fff0f8,#e8f4ff);border:2px solid var(--pink);border-radius:10px;padding:12px 18px;margin-top:12px;font-family:'Fredoka One',cursive;color:var(--pink-dark);}

/* Practice questions */
.q-block{background:var(--card);border-radius:var(--radius);padding:18px;margin-bottom:14px;border:1px solid var(--border);}
.q-block p{font-size:.93rem;line-height:1.65;margin-bottom:12px;}
.q-options{display:flex;flex-direction:column;gap:8px;margin-bottom:12px;}
.opt-btn{background:rgba(255,255,255,.8);border:2px solid var(--border);border-radius:8px;padding:9px 16px;cursor:pointer;text-align:left;font-family:'Quicksand',sans-serif;font-size:.88rem;transition:all .15s;}
.opt-btn:hover{border-color:var(--blue);background:var(--blue-light);}
.opt-btn.correct{border-color:var(--green);background:#f0fff8;color:#1b5e20;}
.opt-btn.wrong{border-color:#e53935;background:#fff0f0;color:#b71c1c;}
.check-btn{background:var(--pink);color:#fff;border:none;border-radius:8px;padding:9px 20px;cursor:pointer;font-family:'Fredoka One',cursive;font-size:.95rem;transition:.2s;}
.check-btn:hover{background:var(--pink-dark);}
.feedback{margin-top:10px;padding:10px 14px;border-radius:8px;font-size:.88rem;display:none;}
.feedback.show{display:block;}
.feedback.correct{background:#f0fff8;border:1px solid var(--green);color:#1b5e20;}
.feedback.wrong{background:#fff0f0;border:1px solid #e53935;color:#b71c1c;}
.answer-input{width:100%;border:2px solid var(--border);border-radius:8px;padding:9px 14px;font-family:'Quicksand',sans-serif;font-size:.9rem;margin-bottom:10px;}
.answer-input:focus{outline:none;border-color:var(--pink);}

/* Visualizer */
.viz-canvas-wrap{background:#1a1a2e;border-radius:var(--radius);padding:16px;margin-bottom:16px;text-align:center;}
canvas{max-width:100%;border-radius:8px;}
.viz-controls{display:flex;gap:10px;flex-wrap:wrap;margin-top:12px;justify-content:center;}
.viz-btn{background:rgba(255,255,255,.1);border:1px solid rgba(255,255,255,.2);color:#eee;border-radius:8px;padding:7px 16px;cursor:pointer;font-family:'Quicksand',sans-serif;font-size:.85rem;transition:.2s;}
.viz-btn:hover,.viz-btn.active{background:var(--blue);border-color:var(--blue);}
.viz-label{color:#bbb;font-size:.82rem;text-align:center;margin-top:8px;}

/* Section navigation */
.section-nav{display:flex;justify-content:space-between;align-items:center;margin-top:32px;padding-top:20px;border-top:1px solid var(--border);}
.nav-arrow{background:#fff;border:2px solid var(--border);border-radius:10px;padding:10px 20px;cursor:pointer;font-family:'Fredoka One',cursive;font-size:.95rem;color:var(--text-light);transition:.2s;}
.nav-arrow:hover{border-color:var(--pink);color:var(--pink);}
.nav-arrow:disabled,.nav-arrow.disabled{opacity:.35;pointer-events:none;}

/* Practical */
.practical-badge{background:linear-gradient(135deg,var(--green),#2e7d52);color:#fff;border-radius:var(--radius);padding:14px 20px;margin-bottom:16px;font-size:.9rem;}
.practical-badge strong{font-family:'Fredoka One',cursive;font-size:1rem;}

/* Responsive */
@media(max-width:640px){
  .section{padding:18px 12px;}
  .hero{padding:22px 16px;}
  .hero h1{font-size:1.5rem;}
  .tab-btn,.nav-tab{padding:9px 10px;font-size:.78rem;}
  .objectives-grid{grid-template-columns:1fr;}
}

@media print{
  .tabs-wrap,.nav-tabs-wrap,.section-nav,header{display:none!important;}
  .section{display:block!important;padding:10px 0!important;}
  body{background:#fff;}
}