* {
    box-sizing: border-box;
}

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

:root {
    --amber-primary: #d84315;
    --amber-secondary: #bf360c;
    --amber-50: #fffbeb;
    --amber-100: #fef3c7;
    --amber-200: #fde68a;
    --amber-300: #fcd34d;
    --amber-700: #b45309;
    --amber-900: #78350f;
    --orange-50: #fff7ed;
    --orange-200: #fed7aa;
    --red-50: #fef2f2;
    --red-200: #fecaca;
    --green-100: #dcfce7;
    --green-700: #15803d;
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
}

body {
    background-color: #fffaf0;
    color: #5d4037;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

.container {
    width: 100%;
    margin-left: auto;
    margin-right: auto;
    padding-left: 1.5rem;
    padding-right: 1.5rem;
    box-sizing: border-box;
}

.max-w-7xl {
    max-width: 80rem;
}

.max-w-5xl {
    max-width: 64rem;
}

/* Navigation */
.nav-bar {
    padding: 1.5rem 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--amber-primary);
    display: flex;
    align-items: center;
    text-decoration: none;
}

.nav-logo i {
    margin-right: 0.5rem;
}

.nav-links {
    display: none;
    gap: 2rem;
}

@media (min-width: 768px) {
    .nav-links {
        display: flex;
    }
}

.nav-right {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.nav-auth {
    display: none;
    align-items: center;
    gap: 0.75rem;
}

@media (min-width: 768px) {
    .nav-auth {
        display: flex;
    }
}

.nav-auth a {
    text-decoration: none;
    color: inherit;
    transition: all 0.15s ease-in-out;
}

.nav-auth a:hover,
.nav-auth a.active {
    color: var(--amber-primary);
}

.nav-auth a.active {
    font-weight: 700;
}

.nav-links a {
    text-decoration: none;
    color: inherit;
    transition: all 0.15s ease-in-out;
}

.nav-links a:hover, .nav-links a.active {
    color: var(--amber-primary);
}

.nav-links a.active {
    font-weight: 700;
}

/* Main Content */
.main-content {
    flex-grow: 1;
    padding-top: 3rem;
    padding-bottom: 3rem;
}

.page-title {
    font-size: 2.25rem;
    font-weight: 700;
    margin-bottom: 1rem;
    text-align: center;
}

.page-subtitle {
    font-size: 1.125rem;
    color: var(--gray-600);
    text-align: center;
    margin-bottom: 4rem;
}

.course-list {
    display: flex;
    flex-direction: column;
    gap: 3rem;
}

/* Course Card */
.course-card {
    background-color: #fff;
    border-radius: 1.5rem;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    display: flex;
    flex-direction: column;
    border: 1px solid var(--amber-100);
    transition: border-color 0.3s, box-shadow 0.3s;
}

@media (min-width: 768px) {
    .course-card {
        flex-direction: row;
    }
}

.course-card:hover {
    border-color: var(--amber-300);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
}

.course-image-container {
    padding: 2rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

@media (min-width: 768px) {
    .course-image-container {
        width: 33.333333%;
    }
}

.course-placeholder-img {
    width: 100%;
    height: 12rem;
    background-color: #fff;
    border-radius: 1rem;
    box-shadow: inset 0 2px 4px 0 rgba(0, 0, 0, 0.06);
    display: flex;
    align-items: center;
    justify-content: center;
}

.course-placeholder-img i {
    font-size: 3.75rem;
}

/* Card Themes */
.theme-amber .course-image-container {
    background-color: var(--amber-50);
}

.theme-amber .course-placeholder-img {
    color: var(--amber-200);
}

.theme-orange .course-image-container {
    background-color: var(--orange-50);
}

.theme-orange .course-placeholder-img {
    color: var(--orange-200);
}

.theme-red .course-image-container {
    background-color: var(--red-50);
}

.theme-red .course-placeholder-img {
    color: var(--red-200);
}

.course-content {
    padding: 2rem;
}

@media (min-width: 768px) {
    .course-content {
        width: 66.666667%;
    }
}

.course-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 1rem;
}

.course-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin: 0;
    color: var(--amber-900);
}

.theme-red .course-title {
    color: var(--gray-700);
}

.course-status {
    font-size: 0.75rem;
    font-weight: 700;
    padding: 0.25rem 0.5rem;
    border-radius: 0.25rem;
    text-transform: uppercase;
}

.status-online {
    background-color: var(--green-100);
    color: var(--green-700);
}

.status-building {
    background-color: var(--gray-100);
    color: var(--gray-500);
}

.course-desc {
    color: var(--gray-600);
    margin-bottom: 1.5rem;
    line-height: 1.5;
}

.course-experiments {
    margin-bottom: 2rem;
}

.course-experiments h3 {
    font-size: 0.875rem;
    font-weight: 700;
    color: var(--gray-400);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.75rem;
}

.tag-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.tag {
    background-color: var(--gray-100);
    color: var(--gray-700);
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.875rem;
}

.course-footer {
    opacity: 1;
}

.disabled .course-footer {
    opacity: 0.5;
}

.btn-course {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 0.75rem;
    font-weight: 700;
    text-decoration: none;
    transition: all 0.2s;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
}

.btn-course-primary {
    background-color: var(--amber-primary);
    color: #fff;
}

.btn-course-primary:hover {
    background-color: var(--amber-secondary);
}

.btn-course-outline {
    border: 2px solid var(--gray-200);
    color: var(--gray-400);
}

.btn-course-outline:hover {
    border-color: var(--amber-primary);
    color: var(--amber-primary);
}

.btn-course i {
    font-size: 0.875rem;
    margin-left: 0.5rem;
}

/* Footer */
.footer {
    background-color: var(--gray-100);
    padding: 3rem 1.5rem;
    margin-top: 5rem;
}

.footer-content {
    max-width: 80rem;
    margin: 0 auto;
    text-align: center;
    color: var(--gray-500);
    font-size: 0.875rem;
}

/* Utility classes from style tag in HTML */
.text-amber-primary {
    color: var(--amber-primary);
}

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

.border-amber-primary {
    border-color: var(--amber-primary);
}

.hover-amber-primary:hover {
    background-color: var(--amber-secondary);
}