:root {
    --bg: #0a0a0a;
    --fg: #e6e6e6;
    --accent: #00ff7f;
    --warn: #ffd60a;
    --error: #ff4d4d;
    --muted: #9aa0a6;
    --line: #222;
    --link: #7fbfff;
    --mono: 'Courier New', ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
    --sans: system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, 'Helvetica Neue', Arial, sans-serif;
    --fs-base: 18px;
    --fs-lg: 20px;
    --fs-xl: 32px;
    --fs-xxl: 48px;
    --pad-x: 84px;
    --pad-y: 64px;
    --maxw: 1280px;
}

[data-theme="lecture"] {
    --bg: #ffffff;
    --fg: #0a0a0a;
    --accent: #0b5;
    --warn: #9a6b00;
    --error: #a40000;
    --muted: #555;
    --line: #ddd;
    --link: #065fd4
}

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

html,
body {
    height: 100%
}

body {
    font-family: var(--mono);
    background: var(--bg);
    color: var(--fg);
    line-height: 1.5;
    overflow: hidden
}

a {
    color: var(--link)
}

.toolbar {
    position: fixed;
    z-index: 10000;
    top: 10px;
    left: 10px;
    display: flex;
    gap: 8px;
    align-items: center;
    background: color-mix(in oklab, var(--bg) 85%, transparent);
    border: 1px solid var(--line);
    backdrop-filter: blur(6px);
    padding: 8px 10px;
    border-radius: 10px
}

.toolbar button {
    font: 600 13px var(--sans);
    padding: 6px 10px;
    border-radius: 8px;
    border: 1px solid var(--line);
    background: transparent;
    color: var(--fg);
    cursor: pointer
}

.toolbar .kbd {
    font: 600 12px var(--mono);
    opacity: .75
}

.swiper {
    width: 100%;
    height: 100vh
}

.swiper-slide {
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: var(--pad-y) var(--pad-x);
    border-top: 1px solid var(--line)
}

.slide-content {
    max-width: var(--maxw);
    margin: 0 auto
}

.slide-number {
    position: absolute;
    top: 16px;
    right: 20px;
    font: 12px var(--mono);
    color: var(--muted)
}

.slide-title {
    font-size: var(--fs-xl);
    font-weight: 800;
    letter-spacing: 1px;
    color: var(--fg);
    text-transform: uppercase;
    margin: 0 0 18px
}

.slide-subtitle {
    font-size: var(--fs-lg);
    color: var(--warn);
    margin: 0 0 14px;
    font-weight: 600
}

.slide-text {
    font-size: var(--fs-base);
    color: var(--fg);
    opacity: .95;
    margin: 10px 0 8px
}

.slide-list {
    list-style: none;
    margin: 12px 0
}

.slide-list li {
    position: relative;
    padding-left: 26px;
    margin: 10px 0
}

.slide-list li::before {
    content: ">";
    position: absolute;
    left: 0;
    top: 0;
    color: var(--error);
    font-weight: 700
}

.terminal {
    border: 1px solid var(--accent);
    background: color-mix(in oklab, var(--bg) 70%, black);
    padding: 16px 18px;
    margin: 16px 0;
    border-radius: 10px;
    box-shadow: 0 0 0 1px color-mix(in oklab, var(--accent) 30%, transparent) inset
}

.terminal .ok {
    color: var(--accent);
    font-weight: 700
}

.terminal .warn {
    color: var(--warn);
    font-weight: 700
}

.terminal .err {
    color: var(--error);
    font-weight: 700
}

.time-badge {
    display: inline-block;
    background: var(--error);
    color: #000;
    padding: 6px 12px;
    border-radius: 999px;
    font: 700 12px var(--sans);
    margin: 8px 0 18px
}

.quiz {
    display: grid;
    gap: 10px;
    margin: 14px 0
}

.quiz-option {
    border-left: 4px solid var(--line);
    background: color-mix(in oklab, var(--bg) 80%, transparent);
    padding: 12px 14px;
    border-radius: 8px;
    cursor: pointer
}

.quiz-option[aria-pressed="true"] {
    outline: 2px solid var(--accent)
}

.quiz-option[data-correct="true"].reveal {
    border-left-color: var(--accent);
    background: color-mix(in oklab, var(--accent) 12%, var(--bg))
}

.quiz-option[data-correct="false"].reveal {
    border-left-color: var(--error);
    background: color-mix(in oklab, var(--error) 10%, var(--bg))
}

.center-big {
    text-align: center;
    font-size: var(--fs-xxl);
    line-height: 1.2;
    margin: 22px 0
}

.note {
    font: 600 13px var(--sans);
    color: var(--muted);
    margin-top: 6px
}

.kbd {
    display: inline-block;
    border: 1px solid var(--line);
    border-bottom-width: 2px;
    border-radius: 6px;
    padding: 0 6px;
    font: 700 12px var(--mono)
}

.swiper-button-next,
.swiper-button-prev {
    color: var(--accent) !important;
    background: color-mix(in oklab, var(--bg) 70%, transparent);
    border: 1px solid var(--line);
    width: 42px;
    height: 42px
}

.swiper-pagination-progressbar {
    background: var(--line) !important
}

.swiper-pagination-progressbar-fill {
    background: var(--accent) !important
}

/* Print handout */
@media print {
    body {
        overflow: visible
    }

    .toolbar,
    .swiper-button-next,
    .swiper-button-prev,
    .swiper-pagination {
        display: none !important
    }

    .swiper-slide {
        height: auto;
        border: 0;
        padding: 28px 36px;
        page-break-inside: avoid
    }

    .slide-title {
        text-transform: none
    }
}

.cols-2 {
    columns: 2;
    column-gap: 28px
}

@media (max-width: 900px) {
    .cols-2 {
        columns: 1
    }
}

[data-density="dense"] {
    --fs-base: 16px;
    --fs-lg: 18px;
    --fs-xl: 28px;
    --fs-xxl: 40px;
    --pad-x: 56px;
    --pad-y: 40px;
    --maxw: 1400px
}

[data-density="dense"] .slide-text {
    margin: 6px 0 4px;
    line-height: 1.35
}

[data-density="dense"] .terminal {
    padding: 12px 14px;
    margin: 10px 0
}

[data-density="dense"] .slide-title {
    margin: 0 0 12px
}

[data-density="dense"] .slide-list li {
    margin: 6px 0
}

section img {
    width:200px;
    height: auto;
    align-self: center;
}

section img.big{
    width:100%;
}