/* CSS */

/* 1. Settings (Tokens) */
:root {
    /* Colors */
    --color-background: #ffffff;
    --color-surface: #f9fafb;
    --color-border: #e5e7eb;
    --color-border-dark: #d1d5db;
    --color-ink: #111827;
    --color-ink-muted: #6b7280;
    --color-ui-tab: #2563eb;

    /* Typography */
    --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
    --step-0: clamp(1.00rem, 0.95rem + 0.25vw, 1.125rem);
    --step-1: clamp(1.125rem, 1.05rem + 0.38vw, 1.375rem);
    --step-2: clamp(1.35rem, 1.22rem + 0.65vw, 1.78rem);
    --step-3: clamp(1.62rem, 1.41rem + 1.05vw, 2.31rem);
    --step-4: clamp(2.33rem, 1.87rem + 2.31vw, 3.50rem);

    /* Spacing */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-24: 6rem;

    /* Shadows & Radii */
    --radius-md: 0.375rem;
    --radius-lg: 0.5rem;
    --shadow-sm-card: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
}

/* 2. Base */
*, *::before, *::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    background-color: var(--color-background);
    color: var(--color-ink);
    font-family: var(--font-sans);
    font-size: var(--step-0);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5 {
    line-height: 1.2;
    letter-spacing: -0.015em;
    font-weight: 700;
    margin: 0;
}

p {
    margin: 0;
}

/* 3. Composition (Layout Primitives) */

.layout-page {
    max-inline-size: 64rem;
    margin-inline: auto;
    padding-inline: clamp(1.5rem, 4vw, 2.5rem);
}

.layout-stack {
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
}

.layout-stack > * + * {
    margin-block-start: var(--space, var(--space-4));
}

.layout-cluster {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space, var(--space-4));
    align-items: center;
}

.layout-sidebar {
    display: flex;
    flex-wrap: wrap;
    gap: clamp(3rem, 6vw, 5rem);
    align-items: center;
}

.layout-sidebar > :first-child {
    flex-basis: 28rem;
    flex-grow: 1;
}

.layout-sidebar > :last-child {
    flex-basis: 0;
    flex-grow: 999;
    min-inline-size: 50%;
}

.layout-grid {
    display: grid;
    gap: var(--space-6);
    grid-template-columns: repeat(auto-fit, minmax(min(250px, 100%), 1fr));
}

.layout-center {
    box-sizing: content-box;
    max-inline-size: var(--measure, 60ch);
    margin-inline: auto;
}

/* Utilities */
.text-center { text-align: center; }

/* 4. Blocks (Components) */

/* Buttons */
.btn-primary {
    background-color: var(--color-ink);
    color: var(--color-background);
    border-radius: var(--radius-md);
    padding: var(--space-3) var(--space-6);
    font-size: 1.125rem;
    font-weight: 600;
    text-align: center;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    transition: background-color 0.15s ease;
    border: none;
    cursor: pointer;
}

.btn-primary:hover, .btn-primary:focus-visible {
    background-color: #000000;
    outline: none;
}

.btn-primary:focus-visible {
    outline: 2px solid var(--color-ink-muted);
    outline-offset: 2px;
}

/* Site Header */
.site-header {
    position: sticky;
    inset-block-start: 0;
    z-index: 50;
    background-color: rgba(255, 255, 255, 0.98);
    border-block-end: 1px solid var(--color-border);
    padding-block: var(--space-4);
}

.site-header__inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.site-header__brand {
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.site-header__logo {
    inline-size: 2rem;
    block-size: 2rem;
    background-color: var(--color-ink);
    color: var(--color-background);
    border-radius: var(--space-1);
    display: flex;
    align-items: center;
    justify-content: center;
}

.site-header__logo svg {
    inline-size: 1rem;
    block-size: 1rem;
}

.site-header__title {
    font-weight: 600;
    font-size: 1.25rem;
    letter-spacing: -0.025em;
    color: var(--color-ink);
}

.site-header__link {
    font-weight: 500;
    font-size: 0.875rem;
    color: var(--color-ink-muted);
    text-decoration: none;
    transition: color 0.2s ease;
}

.site-header__link:hover {
    color: var(--color-ink);
}

/* Hero Section */
.hero {
    padding-block: clamp(4rem, 10vh, 6rem);
    background-color: var(--color-background);
}

.hero__inner {
    --space: var(--space-6);
}

.hero__title {
    font-size: var(--step-4);
}

.hero__text {
    font-size: var(--step-1);
    color: var(--color-ink-muted);
    font-weight: 400;
}

.hero__actions {
    margin-block-start: var(--space-4);
}

.hero__meta {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    font-size: 0.875rem;
    color: var(--color-ink-muted);
    margin-block-start: var(--space-6);
}

.hero__meta-icon {
    inline-size: 1rem;
    block-size: 1rem;
}

/* Step Sections */
.step-section {
    padding-block: clamp(4rem, 8vh, 6rem);
    border-block-start: 1px solid var(--color-border);
    background-color: var(--color-surface);
}

.step-section__content {
    --space: var(--space-4);
}

.step-label {
    align-self: flex-start;
    border: 1px solid var(--color-border);
    color: var(--color-ink-muted);
    font-weight: 500;
    padding: var(--space-1) var(--space-2);
    border-radius: var(--space-1);
    font-size: 0.75rem;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    background-color: var(--color-background);
}

.step-section__title {
    font-size: var(--step-3);
}

.step-section__text {
    font-size: var(--step-0);
    color: var(--color-ink-muted);
}

.step-section__visual {
    display: flex;
    justify-content: center;
}

/* Extension Mockup */
.extension-mockup {
    inline-size: 100%;
    max-inline-size: 320px;
    block-size: 500px;
    background-color: #fafafa;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    display: flex;
    flex-direction: column;
    box-shadow: var(--shadow-sm-card);
    margin-inline: auto;
}

.mockup-tabs {
    display: flex;
    background-color: var(--color-background);
    border-block-end: 1px solid var(--color-border);
}

.mockup-tab {
    flex: 1;
    text-align: center;
    padding-block: var(--space-3);
    font-size: 0.875rem;
    position: relative;
}

.mockup-tab--active {
    font-weight: 600;
    color: #000;
}

.mockup-tab--active::after {
    content: '';
    position: absolute;
    inset-block-end: -1px;
    inset-inline-start: 0;
    inset-inline-end: 0;
    block-size: 2px;
    background-color: var(--color-ui-tab);
}

.mockup-tab--inactive {
    color: var(--color-ink-muted);
}

.mockup-form {
    padding: var(--space-4);
    --space: var(--space-4);
}

.mockup-form__group {
    display: flex;
    flex-direction: column;
    gap: var(--space-1);
}

.mockup-form__label {
    font-size: 0.75rem;
    font-weight: 600;
    color: #374151;
}

.mockup-form__input {
    inline-size: 100%;
    border: 1px solid var(--color-border-dark);
    border-radius: var(--radius-md);
    padding: var(--space-2) var(--space-3);
    font-size: 0.875rem;
    background-color: var(--color-background);
}

.mockup-form__input--muted {
    color: var(--color-ink-muted);
}

.mockup-form__submit {
    inline-size: 100%;
    background-color: var(--color-ui-tab);
    color: var(--color-background);
    border-radius: var(--radius-md);
    padding-block: var(--space-2);
    font-size: 0.875rem;
    font-weight: 500;
    border: none;
    margin-block-start: var(--space-2);
    opacity: 0.6;
}

.mockup-card {
    background-color: var(--color-background);
    border: 1px solid var(--color-border-dark);
    border-radius: var(--radius-md);
    padding: var(--space-3);
    margin: var(--space-4);
}

.mockup-card--muted {
    opacity: 0.5;
}

.mockup-card__title {
    font-weight: 600;
    font-size: 0.875rem;
    color: #000;
    margin-block-end: var(--space-3);
}

.mockup-card__actions {
    --space: var(--space-2);
    flex-wrap: nowrap;
}

.mockup-btn {
    flex: 1;
    padding-block: var(--space-1);
    border: 1px solid var(--color-border-dark);
    border-radius: var(--space-1);
    background-color: var(--color-background);
    color: #000;
    font-size: 0.875rem;
    text-align: center;
    transition: background-color 0.1s;
    cursor: pointer;
}

.mockup-btn:hover {
    background-color: var(--color-surface);
}

.mockup-btn--disabled {
    cursor: default;
}

.mockup-btn--disabled:hover {
    background-color: var(--color-background);
}

/* Install Section */
.install-section {
    background-color: var(--color-surface);
    padding-block: clamp(4rem, 10vh, 5rem);
    border-block-end: 1px solid var(--color-border);
}

.install-section__title {
    font-size: 1.5rem;
    color: var(--color-ink);
    margin-block-end: var(--space-10);
}

.install-card {
    --space: var(--space-2);
    background-color: var(--color-background);
    border: 1px solid var(--color-border);
    padding: var(--space-6);
    border-radius: var(--radius-lg);
    text-align: left;
}

.install-card__num {
    color: var(--color-ink);
    font-weight: 700;
    font-size: 1.5rem;
}

.install-card__title {
    font-weight: 600;
    font-size: 1.125rem;
}

.install-card__text {
    font-size: 0.875rem;
    color: var(--color-ink-muted);
}

.install-section__action {
    margin-block-start: var(--space-12);
}

/* Footer */
.site-footer {
    background-color: var(--color-background);
    padding-block: var(--space-8);
    text-align: center;
}

.site-footer__text {
    font-size: 0.875rem;
    color: var(--color-ink-muted);
}

/* 5. Exceptions */

.step-section--alt {
    background-color: var(--color-background);
    border-block-end: 1px solid var(--color-border);
}

.step-label--alt {
    background-color: var(--color-surface);
}

.layout-sidebar--reversed {
    flex-direction: row-reverse;
}

/* Switch flex-basis mapping for reversed sidebar */
.layout-sidebar--reversed > :last-child {
    flex-basis: 28rem;
    flex-grow: 1;
    min-inline-size: auto;
}

.layout-sidebar--reversed > :first-child {
    flex-basis: 0;
    flex-grow: 999;
    min-inline-size: 50%;
}