@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');

/* CSS Variables */
:root {
    --background: hsl(244, 7%, 96%);
    --foreground: hsl(0, 0%, 20%);
    --card: hsl(0, 0%, 100%);
    --card-foreground: hsl(0, 0%, 20%);
    --primary: hsl(35, 100%, 50%);
    --primary-foreground: hsl(0, 0%, 100%);
    --secondary: hsl(0, 0%, 100%);
    --secondary-foreground: hsl(0, 0%, 53%);
    --muted: hsl(240, 5%, 96%);
    --muted-foreground: hsl(240, 4%, 46%);
    --accent: hsl(193, 60%, 52%);
    --accent-foreground: hsl(0, 0%, 100%);
    --destructive: hsl(0, 84%, 60%);
    --border: hsl(0, 0%, 88%);
    --input: hsl(0, 0%, 88%);
    --ring: hsl(35, 100%, 50%);
    --radius: 0.75rem;
    --orange: hsl(35, 100%, 50%);
    --yellow: hsl(47, 100%, 56%);
    --cyan: hsl(193, 60%, 52%);
    --navy: hsl(222, 48%, 35%);
    --shadow-sm: 0 2px 8px hsla(0, 0%, 0%, 0.08);
    --shadow-lg: 0 4px 20px hsla(0, 0%, 0%, 0.1);
    --shadow-card: 0 4px 20px hsla(0, 0%, 0%, 0.1);
}

/* Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    border-color: var(--border);
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--background);
    color: var(--foreground);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Utility Classes */
.hidden {
    display: none !important;
}

.min-h-screen {
    min-height: 100vh;
}

.bg-background {
    background-color: var(--background);
}

/* Container */
.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 1rem;
}

.container-full {
    max-width: 100%;
    padding: 0 1rem;
}

@media (min-width: 768px) {
    .container-full {
        padding: 0 2rem;
    }
}

/* Animations */
@keyframes fade-in {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slide-in {
    from {
        opacity: 0;
        transform: translateX(20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.animate-fade-in {
    animation: fade-in 0.5s ease-out;
}

.animate-slide-in {
    animation: slide-in 0.3s ease-out;
}

/* Header */
.header {
    border-bottom: 1px solid var(--border);
    background-color: hsla(0, 0%, 100%, 0.8);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    position: sticky;
    top: 0;
    z-index: 50;
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 0;
    flex-wrap: wrap;
    gap: 1rem;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.header-icon {
    width: 3.5rem;
    height: 3.5rem;
    object-fit: contain;
}

.header-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--foreground);
}

.header-subtitle {
    color: var(--muted-foreground);
    font-size: 0.875rem;
}

/* Main Content */
.main-content {
    padding: 2.5rem 0;
}

/* Intro Section */
.intro-section {
    text-align: center;
    margin-bottom: 2.5rem;
}

.intro-title {
    font-size: 1.875rem;
    font-weight: 700;
    color: var(--foreground);
    margin-bottom: 1rem;
}

@media (min-width: 768px) {
    .intro-title {
        font-size: 2.25rem;
    }
}

.intro-text {
    font-size: 1.125rem;
    color: var(--muted-foreground);
    max-width: 42rem;
    margin: 0 auto;
}

.intro-text strong {
    color: var(--foreground);
}

/* Step Viewer */
.step-viewer {
    background-color: var(--card);
    border-radius: 1rem;
    overflow: hidden;
    box-shadow: var(--shadow-card);
    border: 1px solid var(--border);
}

/* Image Container */
.image-container {
    position: relative;
    background-color: var(--secondary);
    height: calc(100vh - 300px);
    min-height: 300px;
}

.image-wrapper {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.step-image {
    width: 100%;
    height: 100%;
    object-fit: contain;
    cursor: pointer;
    transition: transform 0.3s ease;
}

.step-image:hover {
    transform: scale(1.02);
}

/* Step Counter */
.step-counter {
    position: absolute;
    top: 1rem;
    left: 1rem;
    z-index: 10;
    background-color: hsla(0, 0%, 100%, 0.9);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    padding: 0.5rem 1rem;
    border-radius: 0.75rem;
}

.step-counter span {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--foreground);
}

/* Fullscreen Button */
.fullscreen-btn {
    position: absolute;
    top: 1rem;
    right: 1rem;
    z-index: 10;
    background-color: hsla(0, 0%, 100%, 0.9);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    border: none;
    border-radius: 0.5rem;
    padding: 0.5rem;
    cursor: pointer;
    box-shadow: var(--shadow-lg);
    transition: background-color 0.2s;
}

.fullscreen-btn:hover {
    background-color: var(--card);
}

/* Placeholder */
.placeholder {
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: linear-gradient(to bottom right, var(--muted), var(--secondary));
    padding: 2rem;
}

.placeholder-circle {
    width: 6rem;
    height: 6rem;
    border-radius: 50%;
    background-color: hsla(240, 4%, 46%, 0.2);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1rem;
}

.placeholder-circle span {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--muted-foreground);
}

.placeholder-circle-lg {
    width: 8rem;
    height: 8rem;
}

.placeholder-circle-lg span {
    font-size: 3rem;
}

.placeholder-text {
    font-size: 1.125rem;
    color: var(--muted-foreground);
}

.placeholder-text-lg {
    font-size: 1.25rem;
    color: var(--muted-foreground);
}

/* YouTube Embed */
.youtube-desktop {
    display: none;
    position: absolute;
    bottom: 1rem;
    right: 1rem;
    width: 20rem;
    aspect-ratio: 16 / 9;
    z-index: 20;
    border-radius: 0.5rem;
    overflow: hidden;
    box-shadow: var(--shadow-card);
}

@media (min-width: 768px) {
    .youtube-desktop {
        display: block;
    }
}

.youtube-desktop iframe {
    width: 100%;
    height: 100%;
    border: none;
}

.youtube-mobile {
    width: 100%;
    aspect-ratio: 16 / 9;
    background-color: var(--secondary);
}

@media (min-width: 768px) {
    .youtube-mobile {
        display: none;
    }
}

.youtube-mobile iframe {
    width: 100%;
    height: 100%;
    border: none;
}

/* Navigation Controls */
.nav-controls {
    padding: 1.5rem;
    background-color: var(--card);
    border-top: 1px solid var(--border);
}

.nav-buttons {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    margin-bottom: 1rem;
    flex-wrap: wrap;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1rem;
    font-weight: 500;
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    border: none;
    cursor: pointer;
    transition: all 0.2s;
    font-family: inherit;
}

.btn:disabled {
    opacity: 0.3;
    cursor: not-allowed;
}

.btn-outline {
    background-color: transparent;
    border: 1px solid var(--border);
    color: var(--foreground);
}

.btn-outline:hover:not(:disabled) {
    background-color: var(--muted);
    gap: 0.75rem;
}

.btn-primary {
    background-color: var(--card);
    color: var(--orange);
    border: 1px solid var(--orange);
}

.btn-primary:hover:not(:disabled) {
    background-color: var(--orange);
    color: var(--primary-foreground);
    gap: 0.75rem;
}

.btn-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 2.25rem;
    height: 2.25rem;
    border-radius: 0.5rem;
    border: 1px solid var(--border);
    background-color: transparent;
    cursor: pointer;
    transition: background-color 0.2s;
}

.btn-icon:hover {
    background-color: var(--muted);
}

/* Step Indicators */
.step-indicators {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0 1rem;
    overflow-x: auto;
}

.step-indicator {
    height: 0.75rem;
    border-radius: 9999px;
    transition: all 0.3s;
    cursor: pointer;
    border: none;
}

.step-indicator-inactive {
    width: 0.75rem;
    background-color: hsla(240, 4%, 46%, 0.3);
}

.step-indicator-inactive:hover {
    background-color: hsla(240, 4%, 46%, 0.5);
}

.step-indicator-active {
    width: 3rem;
    background: var(--orange);
    box-shadow: 0 0 20px hsla(35, 100%, 50%, 0.4);
}

/* Progress Bar */
.progress-bar-container {
    width: 100%;
    background-color: var(--secondary);
    border-radius: 9999px;
    height: 0.5rem;
    overflow: hidden;
}

.progress-bar {
    height: 100%;
    background: linear-gradient(to right, var(--yellow), var(--orange));
    border-radius: 9999px;
    transition: width 0.5s ease-out;
}

/* Footer */
.footer {
    border-top: 1px solid var(--border);
    background-color: var(--card);
    margin-top: 4rem;
}

.footer-text {
    text-align: center;
    padding: 1.5rem 0;
    color: var(--muted-foreground);
}

.footer-link {
    color: var(--foreground);
    text-decoration: underline;
    transition: color 0.2s;
}

.footer-link:hover {
    color: var(--orange);
}

/* Fullscreen Modal */
.fullscreen-modal {
    position: fixed;
    inset: 0;
    z-index: 100;
    background-color: var(--background);
    display: flex;
    flex-direction: column;
    animation: fade-in 0.3s ease-out;
}

.fullscreen-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem;
    background-color: var(--card);
    border-bottom: 1px solid var(--border);
    flex-shrink: 0;
}

.fullscreen-title {
    font-size: 1.125rem;
    font-weight: 700;
    color: var(--foreground);
}

.fullscreen-controls {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.zoom-level {
    min-width: 3.75rem;
    text-align: center;
    font-weight: 500;
    color: var(--foreground);
}

.fullscreen-content {
    flex: 1;
    position: relative;
    overflow: hidden;
    background-color: var(--secondary);
}

.fullscreen-image-container {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    cursor: grab;
}

.fullscreen-image-container:active {
    cursor: grabbing;
}

.fullscreen-image {
    max-width: none;
    user-select: none;
    transition: transform 0.2s;
}

@media (max-width: 767px) {
    .fullscreen-image {
        width: 100%;
        height: auto;
    }
}

.fullscreen-placeholder {
    position: absolute;
    inset: 0;
}

.fullscreen-nav {
    flex-shrink: 0;
}

.fullscreen-youtube-mobile {
    flex-shrink: 0;
}