.shell-nav{position:fixed;top:0;left:0;right:0;z-index:2000;background:rgba(26,26,46,0.85);backdrop-filter:blur(24px);-webkit-backdrop-filter:blur(24px);border-bottom:1px solid rgba(255,255,255,0.06)}
.shell-nav.scrolled{background:rgba(15,15,26,0.96);box-shadow:0 4px 30px rgba(0,0,0,0.5)}
.nav-inner{max-width:1280px;margin:0 auto;display:flex;align-items:center;justify-content:space-between;padding:0 32px;height:64px}
.nav-brand{display:flex;align-items:center;gap:12px;text-decoration:none;font-weight:700;font-size:17px;color:#f0f0f0}
.nav-brand .brand-icon{width:34px;height:34px;background:linear-gradient(135deg,#7DB6B1,#5a9e98);border-radius:10px;display:flex;align-items:center;justify-content:center;font-size:15px;font-weight:900;color:#0f0f1a}
.nav-brand span{color:#7DB6B1}
.nav-links{display:flex;align-items:center;gap:4px}
.nav-link{padding:8px 16px;border-radius:8px;text-decoration:none;font-size:14px;font-weight:600;color:#9ca3af}
.nav-link:hover{color:#f0f0f0;background:rgba(255,255,255,0.04)}
.nav-cta{padding:8px 24px;border-radius:8px;background:linear-gradient(135deg,#7DB6B1,#5a9e98);color:#0f0f1a;text-decoration:none;font-size:14px;font-weight:700;display:inline-block}
.nav-cta:hover{transform:translateY(-1px);box-shadow:0 4px 20px rgba(125,182,177,0.25)}
.nav-progress{position:absolute;bottom:-2px;left:0;height:2px;background:linear-gradient(90deg,#7DB6B1,#a3d4cf);width:0%;transition:width 0.1s linear}
.breadcrumbs{display:flex;align-items:center;gap:8px;padding:80px 32px 8px;max-width:1280px;margin:0 auto;font-size:13px;color:#6b7280}
.breadcrumbs a{color:#9ca3af;text-decoration:none}
.breadcrumbs a:hover{color:#7DB6B1}
.breadcrumbs .current{color:#f0f0f0;font-weight:600}
.breadcrumbs .separator{margin:0 2px}
.shell-nav{position:fixed;top:0;left:0;right:0;z-index:2000;background:rgba(26,26,46,0.85);backdrop-filter:blur(24px);-webkit-backdrop-filter:blur(24px);border-bottom:1px solid rgba(255,255,255,0.06)}.shell-nav.scrolled{background:rgba(15,15,26,0.96);box-shadow:0 4px 30px rgba(0,0,0,0.5)}.nav-inner{max-width:1280px;margin:0 auto;display:flex;align-items:center;justify-content:space-between;padding:0 32px;height:64px}.nav-brand{display:flex;align-items:center;gap:12px;text-decoration:none;font-weight:700;font-size:17px;color:#f0f0f0}.nav-brand .brand-icon{width:34px;height:34px;background:linear-gradient(135deg,#7DB6B1,#5a9e98);border-radius:10px;display:flex;align-items:center;justify-content:center;font-size:15px;font-weight:900;color:#0f0f1a}.nav-brand span{color:#7DB6B1}.nav-links{display:flex;align-items:center;gap:4px}.nav-link{padding:8px 16px;border-radius:8px;text-decoration:none;font-size:14px;font-weight:600;color:#9ca3af}.nav-link:hover{color:#f0f0f0;background:rgba(255,255,255,0.04)}.nav-cta{padding:8px 24px;border-radius:8px;background:linear-gradient(135deg,#7DB6B1,#5a9e98);color:#0f0f1a;text-decoration:none;font-size:14px;font-weight:700;display:inline-block}.nav-cta:hover{transform:translateY(-1px);box-shadow:0 4px 20px rgba(125,182,177,0.25)}.nav-progress{position:absolute;bottom:-2px;left:0;height:2px;background:linear-gradient(90deg,#7DB6B1,#a3d4cf);width:0%;transition:width 0.1s linear}.breadcrumbs{display:flex;align-items:center;gap:8px;padding:80px 32px 8px;max-width:1280px;margin:0 auto;font-size:13px;color:#6b7280}.breadcrumbs a{color:#9ca3af;text-decoration:none}.breadcrumbs a:hover{color:#7DB6B1}.breadcrumbs .current{color:#f0f0f0;font-weight:600}.breadcrumbs .separator{margin:0 2px}
:root {
    --primary-blue: #3b82f6;
    --primary-blue-dark: #2563eb;
    --primary-blue-light: #60a5fa;
    --primary-blue-ultra-light: #dbeafe;
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-secondary: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --gradient-success: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --gradient-accent: linear-gradient(135deg, #43e97b 0%, #38f9d7 100%);
    --gradient-background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-card: linear-gradient(145deg, #ffffff 0%, #f8fafc 100%);
    --success: #10b981;
    --warning: #f59e0b;
    --error: #ef4444;
    --info: #3b82f6;
    --gray-50: #f9fafb; --gray-100: #f3f4f6; --gray-200: #e5e7eb;
    --gray-300: #d1d5db; --gray-400: #9ca3af; --gray-500: #6b7280;
    --gray-600: #4b5563; --gray-700: #374151; --gray-800: #1f2937; --gray-900: #111827;
    --shadow-sm: 0 1px 2px 0 rgba(0,0,0,0.05);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0,0,0,0.1), 0 10px 10px -5px rgba(0,0,0,0.04);
    --shadow-2xl: 0 25px 50px -12px rgba(0,0,0,0.25);
    --radius-sm: 0.25rem; --radius-md: 0.5rem; --radius-lg: 0.75rem;
    --radius-xl: 1rem; --radius-2xl: 1.5rem;
    --transition-fast: 0.15s ease-out; --transition-base: 0.3s ease-out; --transition-slow: 0.5s ease-out;
}
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
    font-family: 'Inter', sans-serif;
    background: var(--gradient-background);
    min-height: 100vh;
    color: var(--gray-800);
    line-height: 1.6;
    padding-top: 64px;
}
/* NAVBAR */
.navbar {
    position: sticky; top: 64px; left: 0; right: 0; z-index: 10;
    background: rgba(17, 24, 39, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(255,255,255,0.1);
    height: 64px; display: flex; align-items: center;
    padding: 0 2rem;
}
.navbar-brand {
    font-weight: 700; font-size: 1.2rem; color: #fff;
    background: var(--gradient-success); -webkit-background-clip: text;
    -webkit-text-fill-color: transparent; background-clip: text;
    white-space: nowrap;
}
.navbar-links { display: flex; gap: 0.5rem; margin-left: auto; }
.navbar-links a {
    color: rgba(255,255,255,0.75); text-decoration: none;
    font-size: 0.85rem; font-weight: 500; padding: 0.4rem 0.8rem;
    border-radius: var(--radius-md); transition: var(--transition-fast);
}
.navbar-links a:hover { color: #fff; background: rgba(255,255,255,0.1); }
.hamburger {
    display: none; background: none; border: none; cursor: pointer;
    margin-left: auto; padding: 0.5rem;
}
.hamburger span {
    display: block; width: 24px; height: 2px; background: #fff;
    margin: 5px 0; transition: var(--transition-fast);
}
@media (max-width: 768px) {
    .hamburger { display: block; }
    .navbar-links {
        display: none; position: absolute; top: 64px; left: 0; right: 0;
        background: rgba(17,24,39,0.95); flex-direction: column;
        padding: 1rem; gap: 0.25rem;
    }
    .navbar-links.open { display: flex; }
    .navbar-links a { padding: 0.75rem 1rem; }
}
/* CONTAINER & CARDS */
.container { max-width: 960px; margin: 0 auto; padding: 2rem 1rem; }
.card {
    background: var(--gradient-card);
    border-radius: var(--radius-2xl);
    box-shadow: var(--shadow-xl);
    padding: 2.5rem;
    margin-bottom: 2rem;
    border-top: 4px solid transparent;
    border-image: var(--gradient-primary) 1;
    transition: transform var(--transition-base), box-shadow var(--transition-base);
    opacity: 0; transform: translateY(30px);
}
.card.visible { opacity: 1; transform: translateY(0); }
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow-2xl); }
.card h2 {
    font-size: 1.75rem; font-weight: 700; margin-bottom: 1.5rem;
    background: var(--gradient-primary); -webkit-background-clip: text;
    -webkit-text-fill-color: transparent; background-clip: text;
}
.card h3 { font-size: 1.25rem; font-weight: 600; margin: 1.5rem 0 0.75rem; color: var(--gray-800); }
.card h4 { font-size: 1.05rem; font-weight: 600; margin: 1rem 0 0.5rem; color: var(--gray-700); }
.card p { margin-bottom: 0.75rem; color: var(--gray-600); }
/* SIM CONTAINER */
.sim-container {
    background: var(--gray-50); border-radius: var(--radius-xl);
    padding: 1.5rem; margin: 1rem 0;
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.06);
    border: 1px solid var(--gray-200);
}
.sim-container canvas {
    border-radius: var(--radius-lg); border: 1px solid var(--gray-200);
    display: block; max-width: 100%; height: auto;
}
/* BUTTONS */
.btn {
    display: inline-flex; align-items: center; justify-content: center;
    padding: 0.6rem 1.25rem; border: none; border-radius: var(--radius-lg);
    font-family: inherit; font-size: 0.9rem; font-weight: 600;
    cursor: pointer; transition: all var(--transition-fast);
    position: relative; overflow: hidden;
}
.btn::after {
    content: ''; position: absolute; top: 0; left: -100%; width: 100%; height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
    transition: left 0.5s;
}
.btn:hover::after { left: 100%; }
.btn-primary { background: var(--gradient-primary); color: #fff; }
.btn-primary:hover { box-shadow: 0 4px 15px rgba(102,126,234,0.4); transform: translateY(-1px); }
.btn-success { background: var(--gradient-accent); color: var(--gray-800); }
.btn-danger { background: var(--gradient-secondary); color: #fff; }
.btn-sm { padding: 0.4rem 0.9rem; font-size: 0.8rem; }
.btn-group { display: flex; flex-wrap: wrap; gap: 0.5rem; margin: 0.75rem 0; }
/* PILL BUTTONS */
.pill {
    padding: 0.5rem 1.2rem; border-radius: 50px; border: 2px solid var(--gray-300);
    background: #fff; font-family: inherit; font-weight: 600; font-size: 0.9rem;
    cursor: pointer; transition: all var(--transition-fast);
}
.pill:hover { border-color: var(--primary-blue); }
.pill.active-alpha { background: #fecaca; border-color: #ef4444; color: #991b1b; }
.pill.active-beta { background: #bfdbfe; border-color: #3b82f6; color: #1e40af; }
.pill.active-gamma { background: #bbf7d0; border-color: #22c55e; color: #166534; }
/* INPUTS */
.input-group { display: flex; flex-wrap: wrap; gap: 0.75rem; align-items: end; margin: 0.75rem 0; }
.input-group label { display: flex; flex-direction: column; font-size: 0.85rem; font-weight: 500; color: var(--gray-600); }
.input-group input, .input-group select {
    padding: 0.5rem 0.75rem; border: 1.5px solid var(--gray-300);
    border-radius: var(--radius-md); font-family: inherit; font-size: 0.9rem;
    margin-top: 0.25rem; transition: border-color var(--transition-fast);
    width: 140px;
}
.input-group input:focus, .input-group select:focus { outline: none; border-color: var(--primary-blue); box-shadow: 0 0 0 3px var(--primary-blue-ultra-light); }
/* RESULTS */
.result-box {
    background: #fff; border-radius: var(--radius-lg); padding: 1rem 1.25rem;
    margin-top: 0.75rem; border-left: 4px solid var(--primary-blue);
    opacity: 0; transform: translateY(10px);
    transition: opacity var(--transition-base), transform var(--transition-base);
}
.result-box.show { opacity: 1; transform: translateY(0); }
/* KLO BOX */
.klo-box {
    background: var(--primary-blue-ultra-light); border-radius: var(--radius-lg);
    padding: 1rem 1.25rem; margin-bottom: 1rem;
    border-left: 4px solid var(--primary-blue);
}
.klo-box strong { color: var(--primary-blue-dark); }
/* WARNING BOX */
.warning-box {
    background: #fef2f2; border-radius: var(--radius-lg);
    padding: 1rem 1.25rem; margin: 1rem 0;
    border-left: 4px solid var(--error);
}
.warning-box strong { color: var(--error); }
/* INFO BOX */
.info-box {
    background: #eff6ff; border-radius: var(--radius-lg);
    padding: 1rem 1.25rem; margin: 1rem 0;
    border-left: 4px solid var(--info);
}
/* EQUATION */
.equation {
    font-size: 1.1rem; font-weight: 500; text-align: center;
    padding: 0.75rem; background: var(--gray-50); border-radius: var(--radius-md);
    margin: 0.5rem 0; font-family: 'Inter', serif;
}
sup, sub { font-size: 0.7em; }
/* NOTIFICATION */
.notification {
    position: fixed; top: 80px; right: 20px; z-index: 2000;
    padding: 1rem 1.5rem; border-radius: var(--radius-lg);
    color: #fff; font-weight: 500; box-shadow: var(--shadow-lg);
    transform: translateX(120%); transition: transform var(--transition-base);
    max-width: 350px;
}
.notification.show { transform: translateX(0); }
.notification.success { background: var(--success); }
.notification.error { background: var(--error); }
.notification.info { background: var(--info); }
/* DIGITAL DISPLAY */
.digital-display {
    font-family: 'Courier New', monospace; font-size: 1.5rem; font-weight: 700;
    background: #111; color: #0f0; padding: 0.5rem 1rem;
    border-radius: var(--radius-md); display: inline-block;
    min-width: 120px; text-align: center;
    box-shadow: inset 0 2px 6px rgba(0,0,0,0.5);
}
/* GRID */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem; }
@media (max-width: 700px) { .grid-2 { grid-template-columns: 1fr; } }
/* SCENARIO CARD */
.scenario-card {
    background: #fff; border-radius: var(--radius-lg); padding: 1.5rem;
    border: 2px solid var(--gray-200); text-align: center;
}
.scenario-card p { font-size: 1.05rem; color: var(--gray-700); margin-bottom: 1rem; min-height: 3em; }
.scenario-feedback {
    padding: 0.75rem; border-radius: var(--radius-md); margin-top: 0.75rem;
    font-weight: 500; display: none;
}
.scenario-feedback.correct { display: block; background: #d1fae5; color: #065f46; }
.scenario-feedback.incorrect { display: block; background: #fee2e2; color: #991b1b; }
/* QUIZ */
.quiz-question {
    background: #fff; border-radius: var(--radius-lg); padding: 1.25rem;
    margin-bottom: 1rem; border: 1px solid var(--gray-200);
}
.quiz-question p { font-weight: 600; color: var(--gray-800); margin-bottom: 0.75rem; }
.quiz-option {
    display: block; width: 100%; text-align: left;
    padding: 0.6rem 1rem; margin: 0.35rem 0; border: 1.5px solid var(--gray-200);
    border-radius: var(--radius-md); background: #fff;
    font-family: inherit; font-size: 0.9rem; cursor: pointer;
    transition: all var(--transition-fast);
}
.quiz-option:hover { border-color: var(--primary-blue); background: var(--primary-blue-ultra-light); }
.quiz-option.selected { border-color: var(--primary-blue); background: var(--primary-blue-ultra-light); font-weight: 600; }
.quiz-option.correct { border-color: var(--success); background: #d1fae5; }
.quiz-option.incorrect { border-color: var(--error); background: #fee2e2; }
.quiz-option:disabled { cursor: default; opacity: 0.8; }
.quiz-feedback { padding: 0.75rem; border-radius: var(--radius-md); margin-top: 0.5rem; font-size: 0.9rem; display: none; }
.quiz-feedback.show { display: block; }
/* SCORE BAR */
.score-bar { text-align: center; padding: 1rem; font-size: 1.2rem; font-weight: 700; border-radius: var(--radius-lg); margin-top: 1rem; }
/* SLIDER */
input[type="range"] {
    -webkit-appearance: none; width: 100%; height: 6px;
    border-radius: 3px; background: var(--gray-300); outline: none;
    margin: 0.5rem 0;
}
input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none; width: 20px; height: 20px;
    border-radius: 50%; background: var(--gradient-primary); cursor: pointer;
    box-shadow: var(--shadow-md);
}
/* CHECKBOX */
.checkbox-group { display: flex; flex-wrap: wrap; gap: 1rem; margin: 0.5rem 0; }
.checkbox-group label { display: flex; align-items: center; gap: 0.4rem; font-size: 0.9rem; cursor: pointer; }
/* SVG DIAGRAMS */
.svg-diagram { max-width: 100%; height: auto; margin: 0.5rem 0; }
/* PARTICLE CONTAINER */
.particle-container {
    width: 250px; height: 200px; background: #fff;
    border-radius: var(--radius-lg); border: 1px solid var(--gray-200);
    display: flex; flex-wrap: wrap; align-content: flex-start;
    padding: 5px; overflow: hidden; position: relative;
}
.particle-dot {
    width: 8px; height: 8px; border-radius: 50%; margin: 1px;
    transition: opacity 0.3s, transform 0.3s;
}
.particle-dot.decayed { opacity: 0; transform: scale(0); }
/* PENETRATION DIAGRAM ANIMATION */
@keyframes dashMove { to { stroke-dashoffset: -20; } }
.anim-dash { animation: dashMove 0.5s linear infinite; }
/* SCORE TRACKER */
.score-tracker {
    display: inline-flex; align-items: center; gap: 0.5rem;
    background: var(--gray-100); padding: 0.4rem 1rem;
    border-radius: 50px; font-weight: 600; font-size: 0.9rem;
}
/* LED */
.led {
    width: 14px; height: 14px; border-radius: 50%;
    background: #333; display: inline-block;
    box-shadow: inset 0 1px 3px rgba(0,0,0,0.3);
    transition: background 0.1s;
}
.led.on { background: #0f0; box-shadow: 0 0 8px #0f0, inset 0 1px 3px rgba(0,0,0,0.1); }
/* FOOTER */
.footer {
    text-align: center; padding: 2rem; color: rgba(255,255,255,0.6);
    font-size: 0.85rem;
}
@media (max-width: 600px) {
    .card { padding: 1.5rem; }
    .card h2 { font-size: 1.4rem; }
    .sim-container { padding: 1rem; }
}