/* Reset & Base Variables */
:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --secondary: #f3f4f6;
    --accent: #10b981;
    --text-main: #1f2937;
    --text-light: #6b7280;
    --bg-color: #ffffff;
    --card-bg: #ffffff;
    --border-color: #e2e8f0; /* Softer, elegant border */
    --danger: #ef4444;
    --success: #22c55e;
    
    --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);
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    --transition: all 0.3s ease;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.6;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

/* 16:9 App Container Constraint for Desktop */
.app-container {
    width: 100%;
    max-width: 1280px;
    height: 100vh;
    max-height: 720px; /* 16:9 ratio based on 1280 width */
    background-color: var(--bg-color);
    position: relative;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    box-shadow: var(--shadow-lg);
    /* Latar belakang solid white */
}

@media (max-width: 1280px) {
    .app-container {
        height: 100vh;
        max-height: none;
    }
}

/* Typography */
h1, h2, h3, h4 {
    color: var(--text-main);
    font-weight: 700;
    line-height: 1.2;
}

/* Utilities */
.hidden { display: none !important; }
.text-center { text-align: center; }
.mt-4 { margin-top: 1rem; }

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    border-radius: var(--radius-md);
    font-weight: 500;
    cursor: pointer;
    border: none;
    transition: var(--transition);
    font-size: 0.95rem;
}

.btn-primary {
    background-color: var(--primary);
    color: white;
}
.btn-primary:hover {
    background-color: var(--primary-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-accent {
    background-color: var(--accent);
    color: white;
}
.btn-accent:hover {
    filter: brightness(0.9);
    transform: translateY(-1px);
}

.btn-outline {
    background-color: transparent;
    color: var(--primary);
    border: 1px solid var(--primary);
}
.btn-outline:hover {
    background-color: #eff6ff;
}

.btn-large {
    padding: 0.75rem 1.5rem;
    font-size: 1.1rem;
}

.btn-small {
    padding: 0.25rem 0.5rem;
    font-size: 0.85rem;
}

/* Header */
header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
    background-color: var(--card-bg);
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    z-index: 10;
}

.header-logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-weight: 700;
    font-size: 1.2rem;
    color: var(--primary);
}

.header-nav {
    display: flex;
    gap: 1rem;
}

.nav-btn {
    background: none;
    border: none;
    cursor: pointer;
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--text-light);
    transition: var(--transition);
}
.nav-btn:hover {
    color: var(--primary);
}

/* Footer */
footer {
    padding: 1rem 2rem;
    text-align: center;
    background-color: var(--card-bg);
    border-top: 1px solid var(--border-color);
    font-size: 0.9rem;
    color: var(--text-light);
    z-index: 10;
}

/* Main Content Area */
main {
    flex: 1;
    overflow-y: auto;
    position: relative;
    scroll-behavior: smooth;
}

.page-section {
    padding: 2rem 2rem 4rem 2rem;
    animation: fadeIn 0.4s ease-in-out;
    min-height: 100%;
    display: flex;
    flex-direction: column;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.content-wrapper {
    max-width: 900px;
    margin: 0 auto;
    flex: 1;
    width: 100%;
    display: flex;
    flex-direction: column;
}

/* Hero Section (Home) */
#home {
    background-image: url('../images/bg.png');
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    position: relative;
}

/* Optional overlay to ensure text readability if bg is busy */
#home::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(0, 0, 0, 0.65); /* Semi-transparent black overlay */
    z-index: 0;
    pointer-events: none;
}

.hero {
    display: flex;
    justify-content: center;
    align-items: center;
    flex: 1;
    text-align: center;
}

.hero-content {
    max-width: 600px;
    position: relative;
    z-index: 1;
}

.main-title {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

#home .main-title {
    background: none;
    -webkit-text-fill-color: #ffffff;
    color: #ffffff;
    text-shadow: 0 2px 4px rgba(0,0,0,0.5);
}

.subtitle {
    font-size: 1.1rem;
    color: var(--text-light);
    margin-bottom: 2rem;
}

#home .subtitle {
    color: #f1f5f9;
    text-shadow: 0 1px 3px rgba(0,0,0,0.5);
}

#home .btn-outline {
    background-color: #ffffff;
    color: var(--primary);
    border-color: #ffffff;
    box-shadow: var(--shadow-sm); /* default shadow */
}
#home .btn-outline:hover {
    background-color: #f8fafc;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.hero-actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
    position: relative;
    z-index: 9999;
    pointer-events: auto;
}

.icon-pulse {
    color: var(--primary);
    margin-bottom: 1rem;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

/* Cards & Grids */
.card {
    background-color: var(--card-bg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    padding: 1.5rem;
    border: 1px solid var(--border-color);
}

.card-grid-2 {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.materi-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1rem;
    margin-top: 1.5rem;
}

.materi-card {
    background-color: var(--card-bg);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    border: 1px solid var(--border-color);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.03);
    cursor: pointer;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275); /* Bouncy transition */
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    position: relative;
    overflow: hidden;
}

.materi-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; width: 100%; height: 4px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.4s ease;
}

.materi-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 25px rgba(37, 99, 235, 0.15); /* Soft blue shadow */
    border-color: transparent;
}

.materi-card:hover::before {
    transform: scaleX(1);
}

.materi-card-icon {
    font-size: 1.5rem;
    color: var(--primary);
    margin-bottom: 0.5rem;
}

.materi-card h3 {
    font-size: 1.1rem;
}

/* Section Title */
.section-title {
    font-size: 1.8rem;
    margin-bottom: 0.5rem;
    color: var(--text-main);
}
.section-desc {
    color: var(--text-light);
    margin-bottom: 1.5rem;
}

/* Panduan Page */
.styled-list {
    list-style-type: none;
    padding-left: 0;
}
.styled-list li {
    position: relative;
    padding-left: 1.5rem;
    margin-bottom: 0.5rem;
}
.styled-list li::before {
    content: "•";
    color: var(--primary);
    position: absolute;
    left: 0;
    font-weight: bold;
}
.btn-guide {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}
.guide-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    font-size: 0.95rem;
}
.guide-item button {
    flex: 0 0 140px;
    justify-content: center;
}
.bottom-actions {
    margin-top: 2rem;
    display: flex;
    justify-content: center;
    gap: 1rem;
}

/* Materi Reader */
.materi-header {
    margin-bottom: 1rem;
}
.progress-indicator {
    font-size: 0.85rem;
    color: var(--primary);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.25rem;
}
.materi-title {
    font-size: 2rem;
}
.materi-body {
    flex: 1;
    overflow-y: auto;
    margin-bottom: 1.5rem;
    font-size: 1.05rem;
    line-height: 1.8;
    color: #334155;
    padding-right: 1rem; /* Ruang untuk scrollbar */
}
.materi-body h3 {
    margin-top: 2rem;
    margin-bottom: 1rem;
    color: var(--primary-dark);
    font-size: 1.35rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px dashed var(--border-color);
}
.materi-body h3::before {
    content: '✦';
    color: var(--accent);
    font-size: 1.2rem;
}
.materi-body p {
    margin-bottom: 1.25rem;
    text-align: justify;
}
.materi-body strong {
    color: var(--primary);
    background-color: #eff6ff;
    padding: 0 0.2rem;
    border-radius: 4px;
    font-weight: 600;
}
.materi-body ul {
    margin-bottom: 1.5rem;
    padding-left: 0;
    list-style: none;
}
.materi-body ul li {
    position: relative;
    padding-left: 1.75rem;
    margin-bottom: 0.75rem;
}
.materi-body ul li::before {
    content: '✓';
    position: absolute;
    left: 0;
    top: 0;
    color: var(--success);
    font-weight: bold;
}
.materi-navigation {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}
.center-actions {
    display: flex;
    justify-content: center;
    flex: 1;
}

/* Interactive & Quiz Elements */
.interaksi-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1.5rem;
}
.interaksi-container {
    padding: 2rem;
    min-height: 300px;
}
.quiz-option {
    display: block;
    width: 100%;
    text-align: left;
    padding: 1.25rem 1.5rem;
    background-color: #f8fafc;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    font-size: 1.05rem;
    color: var(--text-main);
    font-weight: 500;
    position: relative;
    overflow: hidden;
}
.quiz-option:hover {
    background-color: #ffffff;
    border-color: var(--primary);
    transform: translateX(10px);
    box-shadow: 0 4px 15px rgba(37, 99, 235, 0.1);
}
.quiz-option::after {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    width: 4px;
    background-color: var(--primary);
    transform: scaleY(0);
    transition: transform 0.3s ease;
}
.quiz-option:hover::after {
    transform: scaleY(1);
}
.quiz-option.correct {
    background-color: #dcfce7;
    border-color: var(--success);
    color: #166534;
}
.quiz-option.wrong {
    background-color: #fee2e2;
    border-color: var(--danger);
    color: #991b1b;
}

/* Matching Game */
.match-container {
    display: flex;
    justify-content: space-between;
    gap: 2rem;
    margin-top: 1rem;
}
.match-col {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}
.match-item {
    padding: 1rem;
    background: var(--secondary);
    border: 2px solid transparent;
    border-radius: var(--radius-md);
    cursor: pointer;
    text-align: center;
    transition: var(--transition);
    user-select: none;
}
.match-item.selected {
    border-color: var(--primary);
    background: #eff6ff;
}
.match-item.matched {
    background-color: #dcfce7;
    border-color: var(--success);
    color: #166534;
    cursor: default;
}

/* Sortable List */
.sort-list {
    list-style: none;
    margin-top: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}
.sort-item {
    padding: 1rem;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: var(--shadow-sm);
}
.sort-item-actions button {
    background: var(--secondary);
    border: none;
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    cursor: pointer;
    margin-left: 0.25rem;
}
.sort-item-actions button:hover {
    background: #cbd5e1;
}

/* Feedback Box */
.feedback-box {
    margin-top: 1rem;
    padding: 1rem;
    border-radius: var(--radius-md);
    font-weight: 500;
}
.feedback-box.success {
    background-color: #dcfce7;
    color: #166534;
}
.feedback-box.error {
    background-color: #fee2e2;
    color: #991b1b;
}

.interaction-footer {
    display: flex;
    justify-content: flex-end;
    gap: 1rem;
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border-color);
}

/* Evaluasi */
.evaluasi-card {
    min-height: 400px;
    display: flex;
    flex-direction: column;
    justify-content: center;
}
.quiz-progress {
    font-size: 0.9rem;
    color: var(--text-light);
    margin-bottom: 0.5rem;
}
.quiz-question {
    font-size: 1.25rem;
    margin-bottom: 1.5rem;
}

/* Circle Progress for Score */
.score-display {
    width: 150px;
    height: 150px;
    margin: 0 auto;
}
.circle-bg {
    fill: none;
    stroke: var(--secondary);
    stroke-width: 3.8;
}
.circle {
    fill: none;
    stroke: var(--primary);
    stroke-width: 3.8;
    stroke-linecap: round;
    transition: stroke-dasharray 1s ease-out;
}
.percentage {
    fill: var(--text-main);
    font-size: 0.5em;
    text-anchor: middle;
    font-weight: bold;
}

/* Responsive */
@media (max-width: 768px) {
    .card-grid-2 {
        grid-template-columns: 1fr;
    }
    .main-title {
        font-size: 2rem;
    }
    header {
        flex-direction: column;
        gap: 1rem;
        padding: 1rem;
    }
    .materi-navigation {
        flex-direction: column;
        gap: 1rem;
    }
    .center-actions {
        order: -1;
        width: 100%;
    }
    .center-actions .btn {
        width: 100%;
    }
    .match-container {
        flex-direction: column;
    }
}

/* Simulasi TCP/IP */
.sim-container {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-top: 1.5rem;
}
.sim-computer {
    width: 100%;
    max-width: 400px;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.5rem;
    text-align: center;
}
.sim-layers {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin-top: 1rem;
}
.sim-layer-btn {
    padding: 0.75rem;
    background: var(--secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    cursor: pointer;
    font-weight: 500;
    transition: var(--transition);
}
.sim-layer-btn.active-step {
    background: #eff6ff;
    border-color: var(--primary);
    color: var(--primary-dark);
    box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.2);
}
.sim-layer-btn.done {
    background: #dcfce7;
    border-color: var(--success);
    color: #166534;
    cursor: default;
}
.sim-layer-btn.disabled {
    opacity: 0.5;
    cursor: not-allowed;
    pointer-events: none;
}
.sim-packet-area {
    margin-top: 1.5rem;
    min-height: 80px;
    display: flex;
    justify-content: center;
    align-items: center;
    background: #f8fafc;
    border-radius: var(--radius-md);
    border: 2px dashed var(--border-color);
    padding: 1rem;
    overflow: hidden;
}
.sim-packet {
    display: flex;
    gap: 2px;
    font-size: 0.85rem;
    font-weight: bold;
}
.sim-packet-chunk {
    padding: 0.5rem;
    border-radius: 4px;
    color: white;
    animation: bounceIn 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}
.bg-data { background: #64748b; }
.bg-trans { background: #ef4444; }
.bg-net { background: #eab308; color: black; }
.bg-mac { background: #10b981; }

@keyframes bounceIn {
    0% { transform: scale(0.5); opacity: 0; }
    100% { transform: scale(1); opacity: 1; }
}

.fly-right {
    animation: flyRight 1.5s ease-in forwards;
}
@keyframes flyRight {
    0% { transform: translateX(0); opacity: 1; }
    100% { transform: translateX(300px); opacity: 0; }
}

/* Simulasi Splicing */
.splicing-container {
    display: grid;
    grid-template-columns: 1fr 350px;
    gap: 1.5rem;
    background-color: #0f172a;
    border-radius: 1rem;
    padding: 1.5rem;
    color: #e2e8f0;
    margin-top: 1.5rem;
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.3);
}

.splicing-main {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.splicer-screen-wrapper {
    background-color: #1e293b;
    border-radius: 0.75rem;
    padding: 1.5rem;
    position: relative;
    border: 1px solid #334155;
    height: 300px;
    display: flex;
    justify-content: center;
    align-items: center;
}

.splicer-screen {
    width: 300px;
    height: 200px;
    background-color: #022c0d;
    border: 4px solid #475569;
    border-radius: 8px;
    position: relative;
    overflow: hidden;
    box-shadow: inset 0 0 20px #000;
}

.splicer-grid {
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background-image: 
        linear-gradient(#004d00 1px, transparent 1px),
        linear-gradient(90deg, #004d00 1px, transparent 1px);
    background-size: 25px 25px;
    opacity: 0.5;
}

.splicer-crosshair {
    position: absolute;
    top: 50%; left: 0; right: 0;
    border-top: 1px solid #00ff00;
    opacity: 0.7;
}
.splicer-crosshair.vertical {
    top: 0; bottom: 0; left: 50%; right: auto;
    border-top: none;
    border-left: 1px solid #00ff00;
}

.splicer-data {
    position: absolute;
    font-family: monospace;
    color: #00ff00;
    font-size: 0.85rem;
    z-index: 10;
}
.splicer-data.top-left { top: 10px; left: 10px; }
.splicer-data.bottom-right { bottom: 10px; right: 10px; text-align: right; }

.splicer-fiber {
    position: absolute;
    top: 50%;
    height: 10px;
    background: #e2e8f0;
    transform: translateY(-50%);
    transition: all 1.5s ease;
}
.splicer-fiber.left { left: -150px; width: 140px; border-right: 2px solid #94a3b8; }
.splicer-fiber.right { right: -150px; width: 140px; border-left: 2px solid #94a3b8; }

.splicer-fiber .core {
    position: absolute;
    top: 3px; bottom: 3px;
    background: #fcd34d;
    width: 100%;
}

.arc-flash {
    position: absolute;
    top: 50%; left: 50%;
    width: 40px; height: 40px;
    background: radial-gradient(circle, #fff, #93c5fd, transparent);
    transform: translate(-50%, -50%);
    border-radius: 50%;
    opacity: 0;
    z-index: 20;
}

.arc-flash.active {
    animation: flash 1s ease-in-out;
}

@keyframes flash {
    0% { opacity: 0; transform: translate(-50%, -50%) scale(0.5); }
    10% { opacity: 1; transform: translate(-50%, -50%) scale(1.5); }
    20% { opacity: 0.5; }
    30% { opacity: 1; transform: translate(-50%, -50%) scale(1.2); }
    100% { opacity: 0; transform: translate(-50%, -50%) scale(0.5); }
}

.physical-table {
    background-color: #1e293b;
    border-radius: 0.75rem;
    padding: 1.5rem;
    border: 1px solid #334155;
    height: 120px;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.phys-cable {
    height: 24px;
    background: linear-gradient(to bottom, #3b82f6, #1d4ed8);
    position: relative;
    transition: all 1.5s ease-in-out;
    border-radius: 4px;
    display: flex;
    align-items: center;
}
.phys-cable.left { width: 40%; border-radius: 4px 0 0 4px; justify-content: flex-end;}
.phys-cable.right { width: 40%; border-radius: 0 4px 4px 0; justify-content: flex-start;}

.phys-core {
    position: absolute;
    height: 6px;
    background: #fcd34d;
    width: 0;
    transition: width 1s ease;
}
.phys-cable.left .phys-core { right: -20px; border-radius: 0 3px 3px 0;}
.phys-cable.right .phys-core { left: -20px; border-radius: 3px 0 0 3px;}

.phys-sleeve {
    position: absolute;
    top: 50%; left: 50%;
    transform: translate(-50%, -50%);
    height: 30px; width: 60px;
    background: rgba(255, 255, 255, 0.3);
    border: 1px solid rgba(255, 255, 255, 0.5);
    border-radius: 4px;
    opacity: 0;
    transition: all 1s ease-in-out;
    z-index: 10;
}

.scrap {
    position: absolute;
    background: #3b82f6;
    z-index: 5;
    animation: dropScrap 1s forwards cubic-bezier(0.5, 0, 1, 1);
    border-radius: 2px;
}
.scrap.core-scrap {
    background: #fcd34d;
}
@keyframes dropScrap {
    0% { transform: translateY(0) rotate(0deg); opacity: 1; }
    100% { transform: translateY(80px) rotate(180deg); opacity: 0; }
}

@keyframes heatSleeve {
    0% { background: rgba(255, 255, 255, 0.6); box-shadow: 0 0 0 transparent; }
    50% { background: rgba(239, 68, 68, 0.8); box-shadow: 0 0 20px rgba(239, 68, 68, 0.8); }
    100% { background: rgba(255, 255, 255, 0.6); box-shadow: 0 0 0 transparent; }
}

.splicing-tools {
    background-color: #1e293b;
    border-radius: 0.75rem;
    padding: 1.5rem;
    border: 1px solid #334155;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.instruction-box {
    margin-bottom: 0.5rem;
}
.instruction-box h4 {
    color: #60a5fa;
    margin-bottom: 0.5rem;
}
.instruction-box p {
    font-size: 0.9rem;
    color: #cbd5e1;
}

.tool-grid-splicing {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.75rem;
}

.tool-btn {
    background: #334155;
    border: 1px solid #475569;
    border-radius: 0.5rem;
    padding: 1rem 0.5rem;
    color: #f8fafc;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.85rem;
}

.tool-btn:hover:not(:disabled) {
    background: #475569;
    border-color: #60a5fa;
    transform: translateY(-2px);
}
.tool-btn.active {
    background: rgba(59, 130, 246, 0.2);
    border-color: #3b82f6;
    color: #60a5fa;
}
.tool-btn.done {
    background: rgba(16, 185, 129, 0.1);
    border-color: #10b981;
    color: #34d399;
}
.tool-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.laser-beam {
    position: absolute;
    top: 50%;
    left: 0;
    width: 0;
    height: 4px;
    background: #ff0000;
    box-shadow: 0 0 10px #ff0000, 0 0 20px #ff0000;
    transform: translateY(-50%);
    opacity: 0;
    z-index: 5;
    transition: width 1.5s linear, opacity 0.3s ease;
}

.laser-beam.active {
    width: 100%;
    opacity: 0.8;
    animation: laserPulse 0.1s infinite alternate;
}

@keyframes laserPulse {
    0% { opacity: 0.6; height: 3px; }
    100% { opacity: 1; height: 5px; }
}

@media (max-width: 900px) {
    .splicing-container {
        grid-template-columns: 1fr;
    }
}