:root {
    --obt-red: #D91E2A;
    --obt-red-light: #FF3542;
    --obt-dark: #0A0A0F;
    --obt-dark-2: #12121A;
    --obt-gray: #8A8A9A;
    --obt-light: #F0F0F5;
    --obt-white: #FFFFFF;
    --obt-navy: #1A1A3E;
    --obt-green: #22C55E;
    --obt-red-dim: #EF4444;
}

/* ========== BASE ========== */
.reveal-viewport {
    background: linear-gradient(135deg, var(--obt-dark) 0%, var(--obt-dark-2) 70%, var(--obt-navy) 100%) !important;
}

.reveal {
    font-family: 'Inter', -apple-system, sans-serif;
    font-weight: 400;
    color: var(--obt-light);
}

.reveal .slides {
    text-align: left;
}

.reveal .slides section {
    padding: 22px 40px;
    box-sizing: border-box;
    height: 100%;
    display: flex !important;
    flex-direction: column;
}

/* ========== TYPOGRAPHY ========== */
.reveal h1, .reveal h2, .reveal h3, .reveal h4 {
    font-family: 'Inter', sans-serif;
    font-weight: 600;
    color: var(--obt-white);
    text-transform: none;
    letter-spacing: -0.02em;
    line-height: 1.2;
    margin-bottom: 0.3em;
}

.reveal h1 { font-size: 1.7em; }
.reveal h2 { font-size: 1.25em; }
.reveal h3 { font-size: 0.95em; color: var(--obt-red); }
.reveal h4 { font-size: 0.75em; color: var(--obt-gray); font-weight: 400; }

.reveal p, .reveal li {
    font-size: 0.62em;
    line-height: 1.5;
    color: var(--obt-light);
}

.reveal ul, .reveal ol {
    margin-left: 0;
}

.reveal li {
    margin-bottom: 0.35em;
    list-style: none;
    padding-left: 1.2em;
    position: relative;
}

.reveal li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0.5em;
    width: 5px;
    height: 5px;
    border-radius: 50%;
    background: var(--obt-red);
}

/* ========== SLIDE BACKGROUNDS ========== */
.reveal .slides section {
    background: transparent !important;
}

.reveal .slide-background {
    background: transparent !important;
}

/* Section title slides */
.reveal .slides section.section-title {
    display: flex !important;
    flex-direction: column;
    justify-content: center;
    align-items: flex-start;
    text-align: left;
    height: 100%;
}

.section-title .section-number {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.6em;
    color: var(--obt-red);
    font-weight: 500;
    margin-bottom: 0.4em;
    letter-spacing: 0.1em;
}

.section-title h2 {
    font-size: 1.7em;
    margin-bottom: 0.25em;
}

.section-title .section-subtitle {
    font-size: 0.72em;
    color: var(--obt-gray);
    font-weight: 300;
}

/* ========== TITLE SLIDE ========== */
.title-slide {
    display: flex !important;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center !important;
}

.title-slide .logo-container {
    margin-bottom: 1em;
    position: relative;
    display: inline-block;
}

.title-slide .logo-container::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 180px;
    height: 180px;
    background: radial-gradient(circle, rgba(217,30,42,0.25) 0%, rgba(26,26,62,0.12) 50%, transparent 70%);
    border-radius: 50%;
    animation: logoGlow 4s ease-in-out infinite;
    z-index: 0;
}

.title-slide .logo-container img {
    height: 64px;
    width: auto;
    position: relative;
    z-index: 1;
}

@keyframes logoGlow {
    0%, 100% { opacity: 0.5; transform: translate(-50%, -50%) scale(1); }
    50% { opacity: 1; transform: translate(-50%, -50%) scale(1.15); }
}

.title-slide h1 {
    font-size: 2.1em;
    margin-bottom: 0.2em;
    background: linear-gradient(135deg, var(--obt-white) 0%, var(--obt-light) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    filter: drop-shadow(0 0 30px rgba(217,30,42,0.2));
}

.title-slide .subtitle {
    font-size: 0.8em;
    color: var(--obt-gray);
    font-weight: 300;
    margin-bottom: 2em;
}

.title-slide .presenter-info {
    text-align: center;
}

.title-slide .presenter-name {
    font-size: 0.75em;
    font-weight: 500;
    color: var(--obt-white);
    margin-bottom: 0.2em;
}

.title-slide .presenter-role {
    font-size: 0.62em;
    color: var(--obt-gray);
    font-weight: 300;
}

.title-slide .event-date {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.55em;
    color: var(--obt-red);
    font-weight: 400;
    margin-top: 0.8em;
    letter-spacing: 0.05em;
}

/* ========== COMPONENTS ========== */

/* Accent line */
.accent-line {
    width: 36px;
    height: 2px;
    background: var(--obt-red);
    border-radius: 2px;
    margin-bottom: 0.4em;
}

/* Concept cards */
.concept-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
    margin-top: 0.4em;
}

.concept-card {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.06);
    border-radius: 8px;
    padding: 10px;
    transition: all 0.3s ease;
}

.concept-card:hover {
    border-color: rgba(217, 30, 42, 0.3);
    background: rgba(255, 255, 255, 0.05);
}

.concept-card .card-icon {
    font-size: 0.8em;
    color: var(--obt-red);
    margin-bottom: 0.15em;
}

.concept-card h4 {
    font-size: 0.6em;
    font-weight: 600;
    color: var(--obt-white);
    margin-bottom: 0.15em;
}

.concept-card p {
    font-size: 0.46em;
    color: var(--obt-gray);
    line-height: 1.5;
    margin: 0;
}

/* Single column card list */
.card-list {
    display: flex;
    flex-direction: column;
    gap: 6px;
    margin-top: 0.4em;
}

.card-list .concept-card {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    padding: 8px 12px;
}

.card-list .card-icon {
    font-size: 0.85em;
    color: var(--obt-red);
    flex-shrink: 0;
    margin-top: 2px;
}

.card-list .card-content h4 {
    margin-bottom: 0.2em;
}

/* Comparison boxes */
.comparison-grid {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 8px;
    margin-top: 0.4em;
}

.comparison-grid-2 {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    margin-top: 0.4em;
}

.comparison-box {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.06);
    border-radius: 8px;
    padding: 10px;
    text-align: center;
    transition: all 0.3s ease;
}

.comparison-box.active {
    border-color: var(--obt-red);
    background: rgba(217, 30, 42, 0.08);
}

.comparison-box .era {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.48em;
    color: var(--obt-red);
    margin-bottom: 0.4em;
    letter-spacing: 0.1em;
}

.comparison-box h4 {
    font-size: 0.65em;
    color: var(--obt-white);
    margin-bottom: 0.15em;
}

.comparison-box p {
    font-size: 0.48em;
    color: var(--obt-gray);
    margin: 0;
}

.comparison-box .icon {
    font-size: 1.2em;
    margin-bottom: 0.2em;
    color: var(--obt-gray);
}

/* Steps */
.step-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 8px;
    margin-top: 0.4em;
}

.step-card {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.06);
    border-radius: 8px;
    padding: 10px;
    text-align: center;
    transition: all 0.3s ease;
}

.step-card:hover {
    border-color: rgba(217, 30, 42, 0.3);
    background: rgba(255, 255, 255, 0.05);
}

.step-number {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: var(--obt-red);
    color: var(--obt-white);
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.5em;
    font-weight: 600;
    margin: 0 auto 0.3em;
}

.step-card h4 {
    font-size: 0.55em;
    font-weight: 600;
    color: var(--obt-white);
    margin-bottom: 0.2em;
}

.step-card p {
    font-size: 0.42em;
    color: var(--obt-gray);
    line-height: 1.3;
    margin: 0;
}

/* Arrow between steps */
.step-arrow {
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--obt-red);
    font-size: 0.8em;
}

/* Code blocks */
.code-block {
    background: rgba(0, 0, 0, 0.4);
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: 8px;
    padding: 12px 16px;
    margin-top: 0.4em;
    overflow-x: auto;
}

.code-block pre {
    margin: 0;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.44em;
    line-height: 1.55;
    color: var(--obt-light);
}

.code-block .code-header {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.42em;
    color: var(--obt-gray);
    margin-bottom: 0.6em;
    padding-bottom: 0.4em;
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.code-keyword { color: #C678DD; }
.code-type { color: #E5C07B; }
.code-string { color: #98C379; }
.code-comment { color: #5C6370; font-style: italic; }
.code-function { color: #61AFEF; }
.code-number { color: #D19A66; }
.code-variable { color: #E06C75; }
.code-operator { color: #56B6C2; }

/* Warning / Takeaway boxes */
.warning-box {
    background: rgba(217, 30, 42, 0.08);
    border-left: 3px solid var(--obt-red);
    border-radius: 0 8px 8px 0;
    padding: 10px 14px;
    margin-top: 0.4em;
}

.warning-box h4 {
    font-size: 0.58em;
    font-weight: 600;
    color: var(--obt-red);
    margin-bottom: 0.3em;
}

.warning-box p {
    font-size: 0.5em;
    color: var(--obt-light);
    margin: 0;
    line-height: 1.5;
}

/* Success box */
.success-box {
    background: rgba(34, 197, 94, 0.08);
    border-left: 3px solid var(--obt-green);
    border-radius: 0 8px 8px 0;
    padding: 10px 14px;
    margin-top: 0.4em;
}

.success-box h4 {
    font-size: 0.58em;
    font-weight: 600;
    color: var(--obt-green);
    margin-bottom: 0.3em;
}

.success-box p {
    font-size: 0.5em;
    color: var(--obt-light);
    margin: 0;
    line-height: 1.5;
}

/* Quote style */
.quote-block {
    border-left: 3px solid var(--obt-red);
    padding-left: 16px;
    margin: 0.5em 0;
}

.quote-block p {
    font-size: 0.9em;
    font-weight: 300;
    color: var(--obt-white);
    font-style: italic;
    line-height: 1.5;
}

.quote-block .quote-author {
    font-size: 0.5em;
    color: var(--obt-gray);
    font-style: normal;
    margin-top: 0.5em;
}

/* Pros / Cons grid */
.pros-cons-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    margin-top: 0.4em;
}

.pros-column, .cons-column {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.06);
    border-radius: 8px;
    padding: 12px;
}

.pros-column {
    border-top: 2px solid var(--obt-green);
}

.cons-column {
    border-top: 2px solid var(--obt-red-dim);
}

.pros-column h4, .cons-column h4 {
    font-size: 0.58em;
    font-weight: 600;
    margin-bottom: 0.5em;
}

.pros-column h4 { color: var(--obt-green); }
.cons-column h4 { color: var(--obt-red-dim); }

.pros-column li::before { background: var(--obt-green); }
.cons-column li::before { background: var(--obt-red-dim); }

/* Vending machine diagram */
.vending-diagram {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: 12px;
    align-items: center;
    margin-top: 0.4em;
}

.vending-side {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.06);
    border-radius: 10px;
    padding: 14px;
    text-align: center;
}

.vending-side.smart {
    border-color: rgba(217, 30, 42, 0.3);
    background: rgba(217, 30, 42, 0.05);
}

.vending-side .side-icon {
    font-size: 1.6em;
    margin-bottom: 0.3em;
}

.vending-side h4 {
    font-size: 0.62em;
    font-weight: 600;
    color: var(--obt-white);
    margin-bottom: 0.4em;
}

.vending-side .side-steps {
    text-align: left;
}

.vending-side .side-steps p {
    font-size: 0.42em;
    color: var(--obt-gray);
    margin: 0.2em 0;
    padding-left: 0.8em;
    position: relative;
}

.vending-side .side-steps p::before {
    content: '>';
    position: absolute;
    left: 0;
    color: var(--obt-red);
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.9em;
}

.vending-vs {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.65em;
    color: var(--obt-gray);
    font-weight: 500;
}

/* Lifecycle flow */
.lifecycle-flow {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    margin-top: 0.5em;
}

.lifecycle-step {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: 8px;
    padding: 10px 12px;
    text-align: center;
    min-width: 100px;
    transition: all 0.3s ease;
}

.lifecycle-step:hover {
    border-color: rgba(217, 30, 42, 0.4);
    background: rgba(255, 255, 255, 0.05);
}

.lifecycle-step .step-icon {
    font-size: 1.0em;
    color: var(--obt-red);
    margin-bottom: 0.3em;
}

.lifecycle-step h4 {
    font-size: 0.5em;
    font-weight: 600;
    color: var(--obt-white);
    margin-bottom: 0.15em;
}

.lifecycle-step p {
    font-size: 0.38em;
    color: var(--obt-gray);
    margin: 0;
}

.lifecycle-arrow {
    color: var(--obt-red);
    font-size: 0.7em;
    flex-shrink: 0;
}

/* Timeline / Story */
.timeline-card {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.06);
    border-radius: 10px;
    padding: 14px;
    margin-top: 0.4em;
}

.timeline-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 0.5em;
}

.timeline-header .timeline-icon {
    font-size: 1.2em;
    color: var(--obt-red);
}

.timeline-header .timeline-meta {
    flex: 1;
}

.timeline-header h4 {
    font-size: 0.62em;
    font-weight: 600;
    color: var(--obt-white);
    margin-bottom: 0.1em;
}

.timeline-header .timeline-date {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.42em;
    color: var(--obt-red);
}

.timeline-body p {
    font-size: 0.48em;
    color: var(--obt-light);
    line-height: 1.6;
    margin-bottom: 0.5em;
}

.timeline-stats {
    display: flex;
    gap: 16px;
    margin-top: 0.4em;
}

.timeline-stat {
    text-align: center;
}

.timeline-stat .stat-value {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.8em;
    font-weight: 600;
    color: var(--obt-red);
}

.timeline-stat .stat-label {
    font-size: 0.38em;
    color: var(--obt-gray);
}

/* Use case cards - 3 column */
.usecase-grid {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 8px;
    margin-top: 0.4em;
}

.usecase-card {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.06);
    border-radius: 8px;
    padding: 10px;
    text-align: center;
    transition: all 0.3s ease;
}

.usecase-card:hover {
    border-color: rgba(217, 30, 42, 0.3);
    background: rgba(255, 255, 255, 0.05);
}

.usecase-card .usecase-icon {
    font-size: 1.1em;
    color: var(--obt-red);
    margin-bottom: 0.25em;
}

.usecase-card h4 {
    font-size: 0.55em;
    font-weight: 600;
    color: var(--obt-white);
    margin-bottom: 0.2em;
}

.usecase-card p {
    font-size: 0.4em;
    color: var(--obt-gray);
    line-height: 1.4;
    margin: 0;
}

/* Recap grid */
.recap-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
    margin-top: 0.4em;
}

.recap-card {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.06);
    border-radius: 8px;
    padding: 10px;
    display: flex;
    align-items: flex-start;
    gap: 10px;
    transition: all 0.3s ease;
}

.recap-card:hover {
    border-color: rgba(217, 30, 42, 0.3);
}

.recap-card .recap-icon {
    font-size: 0.9em;
    color: var(--obt-green);
    flex-shrink: 0;
}

.recap-card h4 {
    font-size: 0.55em;
    font-weight: 600;
    color: var(--obt-white);
    margin-bottom: 0.15em;
}

.recap-card p {
    font-size: 0.42em;
    color: var(--obt-gray);
    margin: 0;
}

/* Agenda items */
.agenda-list {
    display: flex;
    flex-direction: column;
    gap: 7px;
    margin-top: 0.5em;
}

.agenda-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 8px 12px;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.06);
    border-radius: 10px;
    transition: all 0.3s ease;
}

.agenda-item:hover {
    border-color: rgba(217, 30, 42, 0.3);
    background: rgba(255, 255, 255, 0.05);
}

.agenda-item .agenda-num {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: var(--obt-red);
    color: var(--obt-white);
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.6em;
    font-weight: 600;
    flex-shrink: 0;
}

.agenda-item .agenda-text {
    font-size: 0.58em;
    color: var(--obt-white);
    font-weight: 500;
}

.agenda-item .agenda-time {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.42em;
    color: var(--obt-gray);
    margin-left: auto;
}

/* Gas analogy */
.gas-diagram {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    margin-top: 0.4em;
}

.gas-side {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.06);
    border-radius: 8px;
    padding: 12px;
    text-align: center;
}

.gas-side .gas-icon {
    font-size: 1.4em;
    margin-bottom: 0.3em;
}

.gas-side h4 {
    font-size: 0.58em;
    color: var(--obt-white);
    margin-bottom: 0.3em;
}

.gas-side p {
    font-size: 0.46em;
    color: var(--obt-gray);
    margin: 0.2em 0;
}


/* ========== CLOSING SLIDE ========== */
.closing-slide {
    display: flex !important;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center !important;
}

.closing-slide h2 {
    font-size: 1.8em;
    margin-bottom: 0.3em;
}

.closing-slide .closing-subtitle {
    font-size: 0.7em;
    color: var(--obt-gray);
    margin-bottom: 1.5em;
}

.social-links {
    display: flex;
    gap: 20px;
    justify-content: center;
    margin-top: 0.8em;
}

.social-link {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.5em;
    color: var(--obt-gray);
    text-decoration: none;
    transition: color 0.3s ease;
}

.social-link:hover {
    color: var(--obt-red);
}

.social-link i {
    font-size: 1.2em;
    color: var(--obt-red);
}

/* ========== ANIMATIONS ========== */
.reveal .slides section .fragment.fade-up {
    opacity: 0;
    transform: translateY(20px);
    transition: all 0.4s cubic-bezier(0.22, 1, 0.36, 1);
}

.reveal .slides section .fragment.fade-up.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Annotated code */
.annotated-code {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    margin-top: 0.4em;
}

.annotated-code .code-block {
    margin-top: 0;
}

.annotation-list {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.annotation-item {
    display: flex;
    align-items: flex-start;
    gap: 6px;
    padding: 6px 10px;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.06);
    border-radius: 8px;
}

.annotation-item .ann-num {
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--obt-red);
    color: var(--obt-white);
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.4em;
    font-weight: 600;
    flex-shrink: 0;
    margin-top: 2px;
}

.annotation-item p {
    font-size: 0.4em;
    color: var(--obt-light);
    margin: 0;
    line-height: 1.5;
}