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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    background: linear-gradient(135deg, #0a0a0a 0%, #0f0f0f 50%, #0a0a0a 100%);
    padding: 20px;
    min-height: 100vh;
    color: #ffffff;
    overflow-x: hidden;
}

/* Tech Grid Background */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image:
        linear-gradient(rgba(0, 129, 201, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0, 129, 201, 0.03) 1px, transparent 1px);
    background-size: 50px 50px;
    pointer-events: none;
    opacity: 0.5;
    z-index: 0;
}

/* Animated Gradient Orb */
body::after {
    content: '';
    position: fixed;
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(0, 129, 201, 0.15) 0%, transparent 70%);
    border-radius: 50%;
    top: -250px;
    right: -250px;
    pointer-events: none;
    animation: float 20s ease-in-out infinite;
    z-index: 0;
}

@keyframes float {

    0%,
    100% {
        transform: translate(0, 0);
    }

    50% {
        transform: translate(-100px, 100px);
    }
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background: linear-gradient(145deg, #161616 0%, #1a1a1a 100%);
    border-radius: 16px;
    box-shadow: 0 20px 60px rgba(0, 129, 201, 0.2);
    overflow: hidden;
    border: 1px solid #252525;
    position: relative;
    z-index: 1;
}

header {
    background: linear-gradient(135deg, #0081C9 0%, #00A8E8 100%);
    color: white;
    padding: 50px 30px;
    text-align: center;
    position: relative;
    overflow: hidden;
}

header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image:
        linear-gradient(rgba(255, 255, 255, 0.05) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255, 255, 255, 0.05) 1px, transparent 1px);
    background-size: 30px 30px;
    pointer-events: none;
}

.logo {
    max-width: 180px;
    height: auto;
    margin-bottom: 25px;
    filter: drop-shadow(0 4px 20px rgba(0, 0, 0, 0.3));
    position: relative;
    z-index: 1;
}

h1 {
    font-size: 2.5em;
    margin-bottom: 15px;
    font-weight: 900;
    letter-spacing: -0.02em;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
    position: relative;
    z-index: 1;
}

.subtitle {
    font-size: 1.15em;
    opacity: 0.95;
    font-weight: 400;
    position: relative;
    z-index: 1;
}

.content {
    padding: 40px 30px;
}

.section {
    margin-bottom: 25px;
    border: 1px solid #252525;
    border-radius: 12px;
    overflow: hidden;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    background: linear-gradient(145deg, #1a1a1a 0%, #1e1e1e 100%);
    position: relative;
}

.section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, #0081C9, #F24E1E);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.section:hover {
    border-color: #0081C9;
    box-shadow: 0 10px 40px rgba(0, 129, 201, 0.15);
}

.section:hover::before {
    transform: scaleX(1);
}

.section-header {
    background: linear-gradient(145deg, #1e1e1e 0%, #222222 100%);
    padding: 22px 25px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    user-select: none;
    transition: all 0.3s ease;
}

.section-header:hover {
    background: linear-gradient(145deg, #252525 0%, #282828 100%);
}

.section-header h2 {
    font-size: 1.4em;
    color: #ffffff;
    font-weight: 700;
}

.toggle-icon {
    font-size: 1.5em;
    color: #0081C9;
    transition: transform 0.3s ease;
}

.section-header.active .toggle-icon {
    transform: rotate(180deg);
}

.section-content {
    padding: 0 25px;
    max-height: 0;
    overflow: hidden;
    transition: all 0.4s ease;
    color: #b8b8b8;
}

.section-content.active {
    padding: 25px;
    max-height: 5000px;
}

.software-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 18px;
    margin: 20px 0;
}

.software-item {
    background: linear-gradient(145deg, #1e1e1e 0%, #222222 100%);
    padding: 18px;
    border-radius: 10px;
    border-left: 4px solid #0081C9;
    transition: all 0.3s ease;
}

.software-item:hover {
    transform: translateX(5px);
    box-shadow: -5px 5px 20px rgba(0, 129, 201, 0.1);
}

.software-item strong {
    color: #0081C9;
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
}

.checklist {
    list-style: none;
    padding-left: 0;
}

.checklist li {
    padding: 14px;
    margin: 10px 0;
    background: linear-gradient(145deg, #1e1e1e 0%, #222222 100%);
    border-radius: 8px;
    padding-left: 45px;
    position: relative;
    transition: all 0.3s ease;
    color: #b8b8b8;
}

.checklist li:hover {
    transform: translateX(5px);
    background: linear-gradient(145deg, #222222 0%, #262626 100%);
}

.checklist li:before {
    content: "✓";
    position: absolute;
    left: 16px;
    color: #0081C9;
    font-weight: bold;
    font-size: 1.3em;
}

.warning-box {
    background: linear-gradient(145deg, #2a2416 0%, #2e2819 100%);
    border-left: 4px solid #ffc107;
    padding: 18px;
    margin: 18px 0;
    border-radius: 8px;
    color: #ffd966;
}

.danger-box {
    background: linear-gradient(145deg, #2a1616 0%, #2e1818 100%);
    border-left: 4px solid #F24E1E;
    padding: 18px;
    margin: 18px 0;
    border-radius: 8px;
    color: #ff9999;
}

.success-box {
    background: linear-gradient(145deg, #162a16 0%, #182e18 100%);
    border-left: 4px solid #0081C9;
    padding: 18px;
    margin: 18px 0;
    border-radius: 8px;
    color: #99ddff;
}

.info-box {
    background: linear-gradient(145deg, #16232a 0%, #18262e 100%);
    border-left: 4px solid #00A8E8;
    padding: 18px;
    margin: 18px 0;
    border-radius: 8px;
    color: #99d6ff;
}

code {
    background: #0a0a0a;
    color: #0081C9;
    padding: 3px 8px;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    font-weight: 600;
}

.code-block {
    background: #0a0a0a;
    color: #0081C9;
    padding: 18px;
    border-radius: 8px;
    margin: 18px 0;
    overflow-x: auto;
    font-family: 'Courier New', monospace;
    border: 1px solid #252525;
}

.temp-guide {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 18px;
    margin: 18px 0;
}

.temp-item {
    padding: 18px;
    border-radius: 10px;
    text-align: center;
    font-weight: 600;
    transition: transform 0.3s ease;
}

.temp-item:hover {
    transform: translateY(-5px);
}

.temp-good {
    background: linear-gradient(145deg, #162a16 0%, #182e18 100%);
    border: 2px solid #0081C9;
    color: #99ddff;
}

.temp-warning {
    background: linear-gradient(145deg, #2a2416 0%, #2e2819 100%);
    border: 2px solid #ffc107;
    color: #ffd966;
}

.temp-danger {
    background: linear-gradient(145deg, #2a1616 0%, #2e1818 100%);
    border: 2px solid #F24E1E;
    color: #ff9999;
}

.decision-box {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 25px;
    margin: 25px 0;
}

.decision-item {
    padding: 25px;
    border-radius: 10px;
    text-align: center;
    transition: transform 0.3s ease;
}

.decision-item:hover {
    transform: translateY(-5px);
}

.pass {
    background: linear-gradient(145deg, #162a16 0%, #182e18 100%);
    border: 3px solid #0081C9;
    color: #ffffff;
}

.pass strong {
    color: #99ddff;
    font-size: 1.3em;
    display: block;
    margin-bottom: 10px;
}

.fail {
    background: linear-gradient(145deg, #2a1616 0%, #2e1818 100%);
    border: 3px solid #F24E1E;
    color: #ffffff;
}

.fail strong {
    color: #ff9999;
    font-size: 1.3em;
    display: block;
    margin-bottom: 10px;
}

h3 {
    color: #0081C9;
    margin: 25px 0 12px 0;
    font-weight: 700;
    font-size: 1.3em;
}

h4 {
    color: #b8b8b8;
    margin: 18px 0 10px 0;
    font-weight: 600;
}

ul {
    margin-left: 25px;
    color: #a8a8a8;
}

ol {
    margin-left: 25px;
    color: #a8a8a8;
}

li {
    margin: 8px 0;
    line-height: 1.7;
}

p {
    color: #b8b8b8;
    line-height: 1.7;
}

a {
    color: #0081C9;
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover {
    color: #00A8E8;
    text-decoration: underline;
}

footer {
    background: linear-gradient(145deg, #1a1a1a 0%, #1e1e1e 100%);
    padding: 30px;
    text-align: center;
    color: #888;
    font-size: 0.95em;
    border-top: 1px solid #252525;
}

footer p {
    color: #888;
    margin: 8px 0;
}

footer p:last-child {
    background: linear-gradient(135deg, #0081C9 0%, #F24E1E 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-weight: 700;
    font-size: 1.1em;
    margin-top: 15px;
}

/* Language Switcher */
.lang-switcher {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1000;
    background: rgba(0, 129, 201, 0.9);
    padding: 10px 15px;
    border-radius: 8px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
    backdrop-filter: blur(5px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: transform 0.3s ease;
}

.lang-switcher:hover {
    transform: scale(1.05);
    background: rgba(0, 129, 201, 1);
}

.lang-switcher a {
    color: white;
    text-decoration: none;
    font-weight: 600;
    font-size: 0.9em;
    display: flex;
    align-items: center;
    gap: 8px;
}

@media (max-width: 768px) {
    h1 {
        font-size: 2em;
    }

    .content {
        padding: 25px 20px;
    }

    .decision-box {
        grid-template-columns: 1fr;
    }

    .temp-guide {
        grid-template-columns: 1fr;
    }

    .software-grid {
        grid-template-columns: 1fr;
    }

    .lang-switcher {
        top: 10px;
        right: 10px;
        padding: 8px 12px;
    }
}

/* QR Code floating */
.qr-code {
    position: fixed;
    bottom: 20px;
    right: 20px;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.9);
    padding: 8px;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
    backdrop-filter: blur(5px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    transition: all 0.3s ease;
    text-align: center;
}

.qr-code img {
    width: 80px;
    height: 80px;
    display: block;
    border-radius: 6px;
}

.qr-code span {
    display: block;
    font-size: 0.7em;
    color: #000;
    font-weight: 700;
    margin-top: 4px;
}

.qr-code:hover {
    transform: scale(1.1);
    background: rgba(255, 255, 255, 1);
}

@media (max-width: 768px) {
    .qr-code {
        bottom: 15px;
        right: 15px;
    }

    .qr-code img {
        width: 60px;
        height: 60px;
    }
}

/* --- Educational Content Components --- */

/* Stat Grid */
.stat-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
    gap: 15px;
    margin-top: 30px;
}

.stat {
    background: rgba(255, 255, 255, 0.1);
    padding: 15px;
    border-radius: 12px;
    backdrop-filter: blur(5px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    text-align: left;
}

.stat strong {
    display: block;
    font-size: 1.4em;
    color: white;
}

.stat span {
    font-size: 0.8em;
    opacity: 0.8;
}

/* Goal Grid */
.goal-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 20px;
    margin: 25px 0;
}

.goal {
    background: #252525;
    padding: 20px;
    border-radius: 12px;
    border-left: 4px solid #F24E1E;
    transition: transform 0.3s ease;
}

.goal:hover {
    transform: translateY(-5px);
}

.goal span {
    font-weight: 800;
    color: #F24E1E;
    font-size: 0.9em;
    text-transform: uppercase;
}

/* Card Grid */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
    margin: 25px 0;
}

.card {
    background: #1e1e1e;
    padding: 25px;
    border-radius: 15px;
    border: 1px solid #333;
    transition: all 0.3s ease;
}

.card:hover {
    border-color: #0081C9;
    background: #222;
}

.card .badge {
    background: rgba(0, 129, 201, 0.2);
    color: #0081C9;
    padding: 4px 12px;
    border-radius: 20px;
    font-weight: 700;
    font-size: 0.85em;
    display: inline-block;
    margin-bottom: 12px;
}

/* Highlight Card */
.highlight-card {
    background: linear-gradient(135deg, rgba(0, 129, 201, 0.1) 0%, rgba(242, 78, 30, 0.1) 100%);
    border: 1px dashed #444;
    padding: 25px;
    border-radius: 15px;
    margin: 30px 0;
}

/* Quiz Styles */
.dq-quiz-item {
    background: #1e1e1e;
    border: 1px solid #252525;
    padding: 25px;
    border-radius: 12px;
    margin-bottom: 25px;
    transition: transform 0.3s ease;
}

.dq-quiz-item:hover {
    transform: translateY(-5px);
    border-color: #0081C9;
}

.dq-question-text {
    font-size: 1.15rem;
    font-weight: 700;
    color: white;
    margin-bottom: 20px;
    display: block;
    line-height: 1.4;
}

.dq-options-list {
    list-style: none;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.dq-option-label {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 14px 18px;
    background: #252525;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
    border: 1px solid transparent;
    font-weight: 500;
}

.dq-option-label:hover {
    background: #2a2a2a;
    border-color: rgba(0, 129, 201, 0.5);
}

.dq-option-label input[type="radio"] {
    accent-color: #0081C9;
    width: 18px;
    height: 18px;
}

.dq-option-label.dq-correct {
    background: rgba(22, 196, 127, 0.1);
    border-color: #16c47f;
    color: #16c47f;
}

.dq-option-label.dq-incorrect {
    background: rgba(242, 78, 30, 0.1);
    border-color: #f24e1e;
    color: #f24e1e;
}

.dq-feedback {
    display: none;
    margin-top: 15px;
    padding: 15px;
    border-radius: 8px;
    font-size: 0.95rem;
    line-height: 1.5;
}

.dq-correct-ans {
    background: rgba(22, 196, 127, 0.1);
    color: #16c47f;
    border-left: 4px solid #16c47f;
    font-weight: 600;
}

.dq-explanation {
    background: rgba(0, 129, 201, 0.1);
    color: #b3e5ff;
    border-left: 4px solid #0081C9;
}

#dq-result-box {
    display: none;
    padding: 30px;
    border-radius: 16px;
    text-align: center;
    margin-top: 40px;
    border: 1px solid #252525;
    animation: fadeIn 0.5s ease;
}

#dq-result-box .score {
    font-size: 2.5rem;
    font-weight: 800;
    display: block;
    margin-bottom: 10px;
}

#dq-result-box .message {
    font-size: 1.2rem;
    opacity: 0.9;
}

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

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

blockquote {
    border-left: 4px solid #0081C9;
    padding-left: 20px;
    margin: 15px 0;
    font-style: italic;
    color: #eee;
}

/* Steps */
.steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin: 25px 0;
}

.step {
    counter-increment: step-counter;
    background: #1e1e1e;
    padding: 20px;
    border-radius: 12px;
    position: relative;
    border: 1px solid #333;
}

.step::before {
    content: counter(step-counter);
    position: absolute;
    top: -15px;
    left: 20px;
    width: 30px;
    height: 30px;
    background: #0081C9;
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    box-shadow: 0 4px 10px rgba(0, 129, 201, 0.3);
}

/* Timeline */
.timeline {
    display: flex;
    flex-direction: column;
    gap: 25px;
    margin: 30px 0;
}

.timeline-card {
    background: #1e1e1e;
    padding: 25px;
    border-radius: 15px;
    border-left: 4px solid #00A8E8;
    position: relative;
}

.timeline-card h3 {
    margin-top: 0;
    color: #00A8E8;
}

/* Component Grid & Topology Grid */
.component-grid,
.topology-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
    margin: 25px 0;
}

.component-card,
.topology-card {
    background: #222;
    padding: 25px;
    border-radius: 15px;
    border-bottom: 4px solid #0081C9;
}

.component-card h3,
.topology-card span.badge {
    color: #0081C9;
    font-size: 1.2em;
    margin-bottom: 15px;
}

.topology-card figure {
    margin-top: 15px;
    border-radius: 8px;
    overflow: hidden;
    background: #fff;
    padding: 10px;
}

.topology-card img {
    max-width: 100%;
    height: auto;
}

/* Comparison Table */
.comparison-table {
    width: 100%;
    border-collapse: collapse;
    margin: 25px 0;
    background: #1e1e1e;
    border-radius: 10px;
    overflow: hidden;
}

.comparison-table th {
    background: #252525;
    padding: 15px;
    text-align: left;
    color: #0081C9;
}

.comparison-table td {
    padding: 15px;
    border-top: 1px solid #333;
    color: #b8b8b8;
}

/* Callout */
.callout {
    background: rgba(0, 129, 201, 0.1);
    border: 1px solid rgba(0, 129, 201, 0.3);
    padding: 20px;
    border-radius: 12px;
    margin: 25px 0;
}

.callout strong {
    color: #0081C9;
}