:root {
    color-scheme: dark;

    --font-sans: "Inter", ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
    --font-display: "Space Grotesk", "Inter", ui-sans-serif, system-ui, sans-serif;
    --font-serif: "Instrument Serif", Georgia, "Times New Roman", serif;
    --font-mono: "JetBrains Mono", ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, monospace;

    --fs-hero: clamp(2.375rem, 1.55rem + 4.1vw, 4.75rem);

    --fs-2xs: clamp(0.6875rem, 0.67rem + 0.09vw, 0.75rem);
    --fs-xs: clamp(0.75rem, 0.72rem + 0.15vw, 0.8125rem);
    --fs-sm: clamp(0.8125rem, 0.78rem + 0.16vw, 0.875rem);
    --fs-base: clamp(0.9375rem, 0.9rem + 0.19vw, 1rem);
    --fs-lg: clamp(1.0625rem, 1.01rem + 0.26vw, 1.125rem);
    --fs-xl: clamp(1.1875rem, 1.1rem + 0.44vw, 1.375rem);
    --fs-2xl: clamp(1.4375rem, 1.3rem + 0.69vw, 1.75rem);
    --fs-3xl: clamp(1.75rem, 1.52rem + 1.15vw, 2.25rem);
    --fs-4xl: clamp(2.125rem, 1.75rem + 1.88vw, 3rem);

    --leading-none: 1;
    --leading-tight: 1.15;
    --leading-snug: 1.3;
    --leading-normal: 1.55;
    --leading-relaxed: 1.7;

    --tracking-tight: -0.022em;
    --tracking-snug: -0.012em;
    --tracking-wide: 0.06em;
    --tracking-mono: 0.08em;

    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-20: 5rem;
    --space-24: 6rem;

    --radius-xs: 0.375rem;
    --radius-sm: 0.5rem;
    --radius-md: 0.75rem;
    --radius-lg: 1rem;
    --radius-xl: 1.375rem;

    --container-max: 76rem;
    --container-narrow: 52rem;
    --container-gutter: clamp(1rem, 4vw, 2rem);
    --prose-max: 70ch;

    --c-bg: #09090d;
    --c-bg-elevated: #0b0c12;
    --c-surface: #101117;
    --c-surface-2: #15161e;
    --c-surface-hover: #1a1b24;
    --c-border: rgba(244, 244, 245, 0.08);
    --c-border-strong: rgba(244, 244, 245, 0.14);
    --c-border-hover: rgba(244, 244, 245, 0.26);
    --c-grid: rgba(244, 244, 245, 0.045);

    --c-text: #f4f4f5;
    --c-text-muted: #a1a1aa;
    --c-text-faint: #6f6f78;
    --c-text-disabled: #52525b;

    --c-success: #4ade80;
    --c-success-tint: rgba(74, 222, 128, 0.09);
    --c-success-border: color-mix(in srgb, var(--c-success) 34%, transparent);
    --c-warning: #fbbf24;
    --c-warning-tint: rgba(251, 191, 36, 0.08);
    --c-warning-border: color-mix(in srgb, var(--c-warning) 34%, transparent);
    --c-danger: #f87171;
    --c-danger-tint: rgba(248, 113, 113, 0.09);
    --c-danger-border: color-mix(in srgb, var(--c-danger) 34%, transparent);

    --c-primary: #818cf8;
    --c-primary-2: #c084fc;
    --c-on-primary: #0b0b14;
    --c-primary-tint: color-mix(in srgb, var(--c-primary) 13%, transparent);
    --c-primary-tint-strong: color-mix(in srgb, var(--c-primary) 22%, transparent);
    --c-primary-border: color-mix(in srgb, var(--c-primary) 34%, transparent);
    --c-primary-glow: color-mix(in srgb, var(--c-primary) 24%, transparent);
    --c-primary-glow-soft: color-mix(in srgb, var(--c-primary) 14%, transparent);

    --c-hover-mix: #ffffff;
    --c-hover-amount: 12%;
    --c-active-amount: 26%;

    --c-primary-hover: color-mix(in srgb, var(--c-primary) calc(100% - var(--c-hover-amount)), var(--c-hover-mix));
    --c-primary-active: color-mix(in srgb, var(--c-primary) calc(100% - var(--c-active-amount)), var(--c-hover-mix));

    --c-bg-glow-a: color-mix(in srgb, var(--c-primary) 16%, transparent);
    --c-bg-glow-b: color-mix(in srgb, var(--c-primary-2) 10%, transparent);
    --c-sheen: linear-gradient(180deg, rgba(255, 255, 255, 0.035), transparent 46%);
    --c-btn-inset: rgba(255, 255, 255, 0.16);
    --c-shadow: rgba(0, 0, 0, 0.32);
    --c-focus-ring: color-mix(in srgb, var(--c-primary) 55%, transparent);
    --c-selection: color-mix(in srgb, var(--c-primary) 26%, transparent);
}

:root[data-mode="light"] {
    color-scheme: light;

    --c-bg: #f7f7f8;
    --c-bg-elevated: #ffffff;
    --c-surface: #ffffff;
    --c-surface-2: #f3f3f5;
    --c-surface-hover: #efeff2;
    --c-border: rgba(9, 9, 11, 0.09);
    --c-border-strong: rgba(9, 9, 11, 0.16);
    --c-border-hover: rgba(9, 9, 11, 0.3);
    --c-grid: rgba(9, 9, 11, 0.05);

    --c-text: #18181b;
    --c-text-muted: #52525b;
    --c-text-faint: #8e8e97;
    --c-text-disabled: #b4b4bc;

    --c-success: #059669;
    --c-success-tint: rgba(5, 150, 105, 0.08);
    --c-success-border: color-mix(in srgb, var(--c-success) 30%, transparent);
    --c-warning: #b45309;
    --c-warning-tint: rgba(180, 83, 9, 0.09);
    --c-warning-border: color-mix(in srgb, var(--c-warning) 32%, transparent);
    --c-danger: #dc2626;
    --c-danger-tint: rgba(220, 38, 38, 0.07);
    --c-danger-border: color-mix(in srgb, var(--c-danger) 30%, transparent);

    --c-primary: #4f46e5;
    --c-primary-2: #9333ea;
    --c-on-primary: #ffffff;
    --c-primary-tint: color-mix(in srgb, var(--c-primary) 9%, transparent);
    --c-primary-tint-strong: color-mix(in srgb, var(--c-primary) 16%, transparent);
    --c-primary-border: color-mix(in srgb, var(--c-primary) 30%, transparent);
    --c-primary-glow: color-mix(in srgb, var(--c-primary) 22%, transparent);
    --c-primary-glow-soft: color-mix(in srgb, var(--c-primary) 10%, transparent);

    --c-hover-mix: #000000;
    --c-hover-amount: 8%;
    --c-active-amount: 18%;

    --c-primary-hover: color-mix(in srgb, var(--c-primary) calc(100% - var(--c-hover-amount)), var(--c-hover-mix));
    --c-primary-active: color-mix(in srgb, var(--c-primary) calc(100% - var(--c-active-amount)), var(--c-hover-mix));

    --c-bg-glow-a: color-mix(in srgb, var(--c-primary) 9%, transparent);
    --c-bg-glow-b: color-mix(in srgb, var(--c-primary-2) 7%, transparent);
    --c-sheen: linear-gradient(180deg, rgba(255, 255, 255, 0.6), transparent 46%);
    --c-btn-inset: rgba(255, 255, 255, 0.32);
    --c-shadow: rgba(9, 9, 11, 0.08);
    --c-focus-ring: color-mix(in srgb, var(--c-primary) 42%, transparent);
    --c-selection: color-mix(in srgb, var(--c-primary) 18%, transparent);
}

body[data-theme="itil"] {
    --c-primary: #38bdf8;
    --c-primary-2: #818cf8;
}

body[data-theme="itil"][data-mode="light"] {
    --c-primary: #0284c7;
    --c-primary-2: #4f46e5;
}

body[data-theme="scrum"] {
    --c-primary: #2dd4bf;
    --c-primary-2: #34d399;
}

body[data-theme="scrum"][data-mode="light"] {
    --c-primary: #0d9488;
    --c-primary-2: #059669;
}

::selection {
    background: var(--c-selection);
    color: var(--c-text);
}

* {
    scrollbar-width: thin;
    scrollbar-color: var(--c-border-strong) transparent;
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: var(--c-border-strong);
    border-radius: 999px;
    border: 2px solid transparent;
    background-clip: content-box;
}

html {
    -webkit-text-size-adjust: 100%;
    text-size-adjust: 100%;
}

body {
    margin: 0;
    min-height: 100dvh;
    isolation: isolate;
    font-family: var(--font-sans);
    font-size: var(--fs-base);
    line-height: var(--leading-normal);
    color: var(--c-text);
    background:
        radial-gradient(62rem 44rem at 86% -12%, var(--c-bg-glow-a), transparent 70%),
        radial-gradient(48rem 36rem at -10% 0%, var(--c-bg-glow-b), transparent 72%),
        var(--c-bg);
    background-attachment: fixed;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

body::before {
    content: "";
    position: fixed;
    inset: 0;
    z-index: 0;
    pointer-events: none;
    background-image: radial-gradient(var(--c-grid) 1px, transparent 1.6px);
    background-size: 28px 28px;
    mask-image: radial-gradient(ellipse 75% 55% at 50% 0%, #000 30%, transparent 78%);
    -webkit-mask-image: radial-gradient(ellipse 75% 55% at 50% 0%, #000 30%, transparent 78%);
}

body::after {
    content: "";
    position: fixed;
    inset: 0;
    z-index: 1;
    pointer-events: none;
    opacity: 0.05;
    background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='160' height='160'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.8' numOctaves='2'/><feColorMatrix type='saturate' values='0'/></filter><rect width='100%25' height='100%25' filter='url(%23n)' opacity='0.6'/></svg>");
}

h1,
h2,
h3 {
    font-family: var(--font-display);
    font-weight: 600;
    letter-spacing: var(--tracking-tight);
}

h1,
h2,
h3,
h4,
h5,
h6 {
    margin: 0;
    color: var(--c-text);
    line-height: var(--leading-tight);
    text-wrap: balance;
}

h1 {
    font-size: var(--fs-hero);
    line-height: 0.98;
    letter-spacing: -0.03em;
}

h2 {
    font-size: var(--fs-4xl);
    line-height: 1.02;
    letter-spacing: -0.025em;
}

h3 {
    font-size: var(--fs-2xl);
    letter-spacing: -0.02em;
}

h4 {
    font-size: var(--fs-xl);
}

h5 {
    font-size: var(--fs-lg);
}

h6 {
    font-size: var(--fs-base);
}

p {
    margin: 0;
}

a {
    color: var(--c-primary);
    text-decoration: none;
    transition: color 0.15s ease;
}

a:hover {
    color: var(--c-primary-hover);
}

ul,
ol {
    margin: 0;
    padding-left: 1.25em;
}

li {
    margin: 0;
    line-height: var(--leading-normal);
}

strong {
    font-weight: 650;
}

small {
    font-size: var(--fs-sm);
}

:focus-visible {
    outline: none;
    box-shadow: 0 0 0 1px var(--c-bg), 0 0 0 3px var(--c-primary), 0 0 0 6px var(--c-focus-ring);
}

.container {
    width: 100%;
    max-width: var(--container-max);
    margin-inline: auto;
    padding-inline: var(--container-gutter);
}

.container--narrow {
    max-width: var(--container-narrow);
}

.container--full {
    max-width: none;
    padding-inline: var(--container-gutter);
}

.section {
    padding-block: clamp(3rem, 7vw, 6rem);
}

.prose {
    max-width: var(--prose-max);
    font-size: var(--fs-lg);
    line-height: var(--leading-relaxed);
}

.prose p + p {
    margin-top: var(--space-4);
}

.prose strong {
    color: var(--c-text);
}

.text-muted {
    color: var(--c-text-muted);
}

.text-faint {
    color: var(--c-text-faint);
}

.text-accent {
    color: var(--c-primary);
}

.mono {
    font-family: var(--font-mono);
    letter-spacing: var(--tracking-mono);
}

.gradient-text {
    background: linear-gradient(115deg, var(--c-primary) 0%, var(--c-primary-2) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.serif-i {
    font-family: var(--font-serif);
    font-style: italic;
    font-weight: 400;
    letter-spacing: -0.01em;
    line-height: 1.1;
}

.text-display {
    font-family: var(--font-display);
    letter-spacing: -0.02em;
}

.text-outline {
    color: transparent;
    -webkit-text-stroke: 1px var(--c-text-faint);
}

.grid-2x2 {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    grid-template-rows: auto;
    gap: var(--space-4);
}

.grid-2x2 > * {
    min-width: 0;
}

.timeline-horizontal {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(100%, var(--timeline-min, 15rem)), 1fr));
    gap: var(--space-4);
    align-items: stretch;
}

.timeline-horizontal > * {
    min-width: 0;
}

.bento-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(min(100%, var(--bento-min, 14rem)), 1fr));
    gap: var(--space-4);
}

.bento-grid > * {
    grid-column: span var(--span-x, 1);
    grid-row: span var(--span-y, 1);
    min-width: 0;
}

.panel {
    position: relative;
    background: var(--c-surface);
    background-image: var(--c-sheen);
    border: 1px solid var(--c-border);
    border-radius: var(--radius-lg);
    padding: var(--space-5);
    color: var(--c-text);
    min-width: 0;
    transition: background-color 0.18s ease, background-image 0.18s ease, border-color 0.18s ease, box-shadow 0.18s ease;
}

.panel::before {
    content: "";
    position: absolute;
    inset: 0 0 auto 0;
    height: 1px;
    border-radius: var(--radius-lg) var(--radius-lg) 0 0;
    background: linear-gradient(90deg, transparent, var(--c-border-hover), transparent);
    opacity: 0;
    transition: opacity 0.18s ease;
    pointer-events: none;
}

.panel:hover::before {
    opacity: 1;
}

.panel--compact {
    padding: var(--space-4);
}

.panel--inset {
    background: var(--c-surface-2);
    background-image: var(--c-sheen);
}

.panel--interactive {
    cursor: pointer;
}

.panel--interactive:hover {
    background-color: var(--c-surface-hover);
    background-image: var(--c-sheen);
    border-color: var(--c-border-strong);
    box-shadow: 0 10px 34px -18px var(--c-shadow);
}

.panel--accent {
    border-color: var(--c-primary-border);
    background-image: linear-gradient(180deg, var(--c-primary-tint-strong), var(--c-surface)), var(--c-sheen);
}

.panel--accent.panel--interactive:hover {
    border-color: var(--c-primary);
    box-shadow: 0 10px 34px -16px var(--c-primary-glow);
}

.panel--success {
    border-color: var(--c-success-border);
    background-color: var(--c-success-tint);
}

.panel--warning {
    border-color: var(--c-warning-border);
    background-color: var(--c-warning-tint);
}

.panel--danger {
    border-color: var(--c-danger-border);
    background-color: var(--c-danger-tint);
}

.panel-title {
    margin: 0;
    font-size: var(--fs-base);
    font-weight: 650;
    line-height: var(--leading-snug);
    letter-spacing: var(--tracking-snug);
    color: var(--c-text);
}

.panel-header {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: var(--space-3);
    margin-bottom: var(--space-3);
}

.panel-footer {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    margin-top: var(--space-4);
    padding-top: var(--space-3);
    border-top: 1px solid var(--c-border);
}

.tag {
    display: inline-flex;
    align-items: center;
    gap: 0.375rem;
    padding: 0.125rem 0.5rem;
    border: 1px solid var(--c-border-strong);
    border-radius: 999px;
    background: transparent;
    background-image: var(--c-sheen);
    color: var(--c-text-muted);
    font-family: var(--font-mono);
    font-size: var(--fs-2xs);
    font-weight: 500;
    line-height: 1.6;
    letter-spacing: var(--tracking-mono);
    text-transform: uppercase;
    white-space: nowrap;
    transition: color 0.15s ease, border-color 0.15s ease, background-color 0.15s ease;
}

.tag--accent {
    color: var(--c-primary);
    border-color: var(--c-primary-border);
    background-color: var(--c-primary-tint);
}

.tag--success {
    color: var(--c-success);
    border-color: var(--c-success-border);
    background-color: var(--c-success-tint);
}

.tag--warning {
    color: var(--c-warning);
    border-color: var(--c-warning-border);
    background-color: var(--c-warning-tint);
}

.tag--danger {
    color: var(--c-danger);
    border-color: var(--c-danger-border);
    background-color: var(--c-danger-tint);
}

.divider {
    height: 1px;
    border: 0;
    background: var(--c-border);
    margin-block: var(--space-4);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    min-height: 2.25rem;
    padding: 0.375rem 0.9375rem;
    border: 1px solid transparent;
    border-radius: var(--radius-md);
    background: transparent;
    color: var(--c-text);
    font-family: var(--font-sans);
    font-size: var(--fs-sm);
    font-weight: 600;
    line-height: 1.2;
    letter-spacing: var(--tracking-snug);
    text-decoration: none;
    white-space: nowrap;
    cursor: pointer;
    user-select: none;
    -webkit-tap-highlight-color: transparent;
    transition: background-color 0.16s ease, border-color 0.16s ease, color 0.16s ease, box-shadow 0.16s ease, filter 0.16s ease;
}

.btn:active {
    transform: none;
}

.btn:disabled,
.btn[aria-disabled="true"] {
    opacity: 0.45;
    cursor: not-allowed;
    pointer-events: none;
}

.btn--primary {
    background-image: linear-gradient(135deg, var(--c-primary) 0%, var(--c-primary-2) 110%);
    box-shadow: inset 0 1px 0 var(--c-btn-inset), 0 1px 2px rgba(0, 0, 0, 0.12), 0 8px 24px -14px var(--c-primary-glow);
    color: var(--c-on-primary);
}

.btn--primary:hover {
    filter: saturate(1.04) brightness(1.05);
    box-shadow: inset 0 1px 0 var(--c-btn-inset), 0 1px 2px rgba(0, 0, 0, 0.12), 0 12px 30px -12px var(--c-primary-glow);
}

.btn--primary:active {
    filter: brightness(0.97);
}

.btn--outline {
    background: var(--c-surface);
    background-image: var(--c-sheen);
    border-color: var(--c-border-strong);
    color: var(--c-text);
}

.btn--outline:hover {
    background: var(--c-surface-hover);
    border-color: var(--c-border-hover);
}

.btn--ghost {
    color: var(--c-text-muted);
}

.btn--ghost:hover {
    background: var(--c-surface-hover);
    color: var(--c-text);
}

.btn--danger {
    color: var(--c-danger);
    border-color: var(--c-danger-border);
    background-color: var(--c-danger-tint);
}

.btn--danger:hover {
    background-color: var(--c-danger-tint);
    border-color: var(--c-danger);
}

.btn--sm {
    min-height: 1.875rem;
    padding: 0.1875rem 0.625rem;
    font-size: var(--fs-xs);
    border-radius: var(--radius-sm);
}

.btn--lg {
    min-height: 2.75rem;
    padding: 0.625rem 1.25rem;
    font-size: var(--fs-base);
}

.option {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    width: 100%;
    padding: var(--space-3) var(--space-4);
    background: var(--c-surface);
    background-image: var(--c-sheen);
    border: 1px solid var(--c-border);
    border-radius: var(--radius-md);
    color: var(--c-text);
    font-family: var(--font-sans);
    font-size: var(--fs-base);
    line-height: var(--leading-snug);
    text-align: left;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
    transition: background-color 0.16s ease, border-color 0.16s ease, box-shadow 0.16s ease;
}

.option:hover {
    background: var(--c-surface-hover);
    background-image: var(--c-sheen);
    border-color: var(--c-border-strong);
}

.option:disabled {
    opacity: 0.82;
    cursor: default;
}

.option[aria-selected="true"],
.option.is-selected {
    background-color: var(--c-primary-tint);
    background-image: linear-gradient(180deg, var(--c-primary-tint-strong), var(--c-surface));
    border-color: var(--c-primary-border);
    box-shadow: 0 6px 20px -14px var(--c-primary-glow);
}

.option.is-correct {
    background-color: var(--c-success-tint);
    background-image: linear-gradient(180deg, var(--c-success-tint), var(--c-surface));
    border-color: var(--c-success-border);
}

.option.is-wrong {
    background-color: var(--c-danger-tint);
    background-image: linear-gradient(180deg, var(--c-danger-tint), var(--c-surface));
    border-color: var(--c-danger-border);
}

.option__marker {
    flex: 0 0 auto;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 1.25rem;
    height: 1.25rem;
    border: 1px solid var(--c-border-strong);
    border-radius: var(--radius-xs);
    color: transparent;
    font-size: var(--fs-2xs);
    line-height: 1;
    transition: background-color 0.16s ease, border-color 0.16s ease, color 0.16s ease, box-shadow 0.16s ease;
}

.option[aria-selected="true"] .option__marker,
.option.is-selected .option__marker {
    background-image: linear-gradient(135deg, var(--c-primary), var(--c-primary-2));
    border-color: transparent;
    color: var(--c-on-primary);
    box-shadow: 0 0 10px var(--c-primary-glow-soft);
}

.option.is-correct .option__marker {
    background: var(--c-success);
    border-color: transparent;
    color: var(--c-bg);
}

.option.is-wrong .option__marker {
    background: var(--c-danger);
    border-color: transparent;
    color: var(--c-bg);
}

.question-text {
    font-size: var(--fs-lg);
    font-weight: 500;
    line-height: var(--leading-relaxed);
    letter-spacing: var(--tracking-snug);
    color: var(--c-text);
}

.field-label {
    display: block;
    margin-bottom: var(--space-2);
    color: var(--c-text-faint);
    font-family: var(--font-mono);
    font-size: var(--fs-xs);
    font-weight: 500;
    letter-spacing: var(--tracking-mono);
    text-transform: uppercase;
}

@media (max-width: 640px) {
    .grid-2x2 {
        grid-template-columns: 1fr;
    }

    .timeline-horizontal {
        grid-auto-flow: column;
        grid-auto-columns: minmax(15rem, 1fr);
        grid-template-columns: none;
        overflow-x: auto;
        scroll-snap-type: x proximity;
    }

    .timeline-horizontal > * {
        scroll-snap-align: start;
    }

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

    .bento-grid > * {
        grid-column: span 1;
        grid-row: span 1;
    }
}

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        transition-duration: 0.001ms !important;
        animation-duration: 0.001ms !important;
    }
}