/* 
 * Fucoidan Research - Main Stylesheet
 * Enterprise-grade Medical Portal Design
 */

:root {
    /* Color Palette - Official Fucoidan Brand */
    --color-primary: #5E3E30; /* Dark Brown */
    --color-primary-dark: #3E2920; 
    --color-secondary: #5E3E30; 
    --color-secondary-dark: #3E2920;
    --color-accent: #E0D7C6;
    --color-text-main: #5E3E30;
    --color-text-muted: #8B7368;
    --color-bg-light: #F5F2EC; /* Official Beige */
    --color-white: #FFFFFF;
    --color-border: #D9D1C1;

    /* Typography */
    --font-heading: 'Inter', 'Poppins', sans-serif;
    --font-body: 'Roboto', 'Open Sans', sans-serif;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;

    /* Effects */
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 12px 24px rgba(0, 0, 0, 0.12);
    --transition-fast: 0.2s ease;
    --transition-medium: 0.3s ease;
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
}

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

body {
    font-family: var(--font-body);
    background-color: var(--color-white);
    color: var(--color-text-main);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

h1,
h2,
h3,
h4,
h5,
h6 {
    font-family: var(--font-heading);
    color: var(--color-primary);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--spacing-sm);
}

a {
    text-decoration: none;
    color: var(--color-primary);
    transition: var(--transition-fast);
}

a:hover {
    color: var(--color-secondary);
}

button {
    cursor: pointer;
    border: none;
    font-family: var(--font-heading);
}

/* Utility Classes */
.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 var(--spacing-sm);
}

.section {
    padding: var(--spacing-xl) 0;
}

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

.text-center {
    text-align: center;
}

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

.text-secondary {
    color: var(--color-secondary);
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: var(--radius-sm);
    font-weight: 600;
    text-align: center;
    transition: all var(--transition-medium);
    font-size: 1rem;
}

.btn-primary {
    background-color: var(--color-primary);
    color: var(--color-white);
    box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
    background-color: var(--color-primary-dark);
    box-shadow: var(--shadow-md);
    transform: translateY(-1px);
}

.btn-secondary {
    background-color: transparent;
    border: 2px solid var(--color-primary);
    color: var(--color-primary);
}

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

.btn-sm {
    padding: 8px 16px;
    font-size: 0.875rem;
}

/* Header & Navigation */
.main-header {
    background: var(--color-white);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 3px solid var(--color-secondary);
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 80px;
}

.logo {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--color-primary);
    display: flex;
    align-items: center;
    gap: 10px;
    z-index: 1002;
}

.logo span {
    color: var(--color-secondary);
}

.main-nav ul {
    display: flex;
    list-style: none;
    gap: var(--spacing-md);
}

.main-nav a {
    color: var(--color-text-main);
    font-weight: 500;
    font-size: 0.95rem;
    position: relative;
}

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

.main-nav a::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: -4px;
    left: 0;
    background-color: var(--color-secondary);
    transition: width var(--transition-fast);
}

.main-nav a:hover::after {
    width: 100%;
}

.search-bar-wrapper {
    position: relative;
    display: none;
    /* Hidden on mobile by default, shown in flexible layout on desktop */
}

@media (min-width: 769px) {
    .search-bar-wrapper {
        display: block;
    }
}

.search-input {
    padding: 10px 16px;
    padding-right: 40px;
    border: 1px solid var(--color-border);
    border-radius: 20px;
    width: 250px;
    font-family: var(--font-body);
    transition: all var(--transition-fast);
}

.search-input:focus {
    outline: none;
    border-color: var(--color-primary);
    width: 300px;
    box-shadow: 0 0 0 3px rgba(0, 51, 102, 0.1);
}

.search-icon {
    position: absolute;
    right: 12px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--color-text-muted);
    pointer-events: none;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #f0f4f8 0%, #ffffff 100%);
    padding: var(--spacing-xl) 0;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 60%;
    height: 100%;
    background:
        radial-gradient(circle at 70% 30%, rgba(0, 51, 102, 0.05) 0%, transparent 60%),
        radial-gradient(circle at 90% 80%, rgba(0, 168, 107, 0.08) 0%, transparent 50%);
    background-image:
        radial-gradient(var(--color-border) 1px, transparent 1px),
        radial-gradient(var(--color-border) 1px, transparent 1px);
    background-size: 40px 40px;
    background-position: 0 0, 20px 20px;
    opacity: 0.6;
    z-index: 0;
    mask-image: linear-gradient(to left, black, transparent);
    -webkit-mask-image: linear-gradient(to left, black, transparent);
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 600px;
}

.hero h1 {
    font-size: 3.5rem;
    margin-bottom: var(--spacing-sm);
    color: var(--color-primary);
    letter-spacing: -0.02em;
}

.hero p {
    font-size: 1.25rem;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-md);
}

.hero-buttons {
    display: flex;
    gap: var(--spacing-sm);
}

/* Disease Grid */
.grid-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.disease-card {
    background: var(--color-white);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    overflow: hidden;
    transition: all var(--transition-medium);
    cursor: pointer;
    position: relative;
}

.disease-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
    border-color: var(--color-secondary);
}

.card-header {
    background: var(--color-bg-light);
    padding: var(--spacing-md);
    border-bottom: 1px solid var(--color-border);
}

.card-header h3 {
    margin: 0;
    font-size: 1.25rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.card-icon {
    font-size: 1.5rem;
    color: var(--color-secondary);
}

.card-body {
    padding: var(--spacing-md);
}

.card-body ul {
    list-style: none;
    padding-left: 0;
}

.card-body li {
    padding: 8px 0;
    border-bottom: 1px solid var(--color-border);
    font-size: 0.9rem;
    color: var(--color-text-muted);
    display: flex;
    align-items: center;
}

.card-body li::before {
    content: '•';
    color: var(--color-secondary);
    font-weight: bold;
    margin-right: 8px;
}

.card-body li:last-child {
    border-bottom: none;
}

/* Research Details (Expandable) */
.research-details {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease-out;
    background: #fafbfc;
    border-top: 1px solid var(--color-border);
}

.research-details.open {
    max-height: 1000px;
    /* Arbitrary large height */
    overflow-y: auto;
}

.study-item {
    padding: var(--spacing-md);
    border-bottom: 1px solid var(--color-border);
}

.study-title {
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: 0.5rem;
    display: block;
}

.study-meta {
    font-size: 0.85rem;
    color: #888;
    margin-bottom: 0.5rem;
    font-style: italic;
}

.mechanism-tag {
    display: inline-block;
    background: rgba(0, 168, 107, 0.1);
    color: var(--color-secondary-dark);
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 0.8rem;
    font-weight: 600;
    margin-top: 5px;
}

/* Info Cards (About/Experts) */
.expert-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: var(--spacing-md);
}

.expert-card {
    background: var(--color-white);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    text-align: center;
}

.expert-img {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    object-fit: cover;
    margin-bottom: var(--spacing-sm);
    border: 3px solid var(--color-accent);
}

/* Popup Ad */
.popup-overlay {
    position: fixed;
    bottom: 20px;
    right: 20px;
    width: 320px;
    background: white;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    z-index: 9999;
    transform: translateY(150%);
    transition: transform 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    border-left: 5px solid var(--color-secondary);
    padding: 0;
    overflow: hidden;
}

.popup-overlay.active {
    transform: translateY(0);
}

.popup-content {
    padding: 20px;
    position: relative;
}

.popup-close {
    position: absolute;
    top: 5px;
    right: 10px;
    font-size: 1.2rem;
    cursor: pointer;
    color: #999;
    background: none;
    border: none;
}

.popup-title {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 5px;
    color: var(--color-primary);
}

.popup-text {
    font-size: 0.9rem;
    color: var(--color-text-muted);
    margin-bottom: 10px;
}

/* Footer */
footer {
    padding: var(--spacing-lg) 0 var(--spacing-md);
    margin-top: var(--spacing-xl);
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
}

.footer-col h4 {
    color: var(--color-secondary);
    margin-bottom: var(--spacing-sm);
    font-size: 1.1rem;
}

.footer-col ul {
    list-style: none;
}

.footer-col ul li {
    margin-bottom: 8px;
}

.footer-col a {
    font-size: 0.95rem;
}

.footer-col a:hover {
    opacity: 0.8;
}

.copyright {
    text-align: center;
    border-top: 1px solid rgba(0, 0, 0, 0.1);
    padding-top: var(--spacing-md);
    font-size: 0.875rem;
}

.mobile-menu-toggle {
    display: none;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-container {
        padding: 0 1rem;
    }

    .main-nav {
        display: none;
        position: absolute;
        top: 80px;
        left: 0;
        width: 100%;
        background: white;
        box-shadow: 0 5px 10px rgba(0, 0, 0, 0.1);
        padding: 20px;
        border-top: 1px solid #eee;
        z-index: 1001;
        max-height: calc(100vh - 80px);
        overflow-y: auto;
    }

    .main-nav.active {
        display: block;
        animation: slideDown 0.3s ease-out;
    }

    .main-nav ul {
        flex-direction: column;
        gap: 15px;
        text-align: center;
    }

    .mobile-menu-toggle {
        display: block !important;
        color: var(--color-primary);
    }

    .search-bar-wrapper {
        display: none;
    }

    .hero h1 {
        font-size: 2.5rem;
    }

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

    .header-actions {
        display: flex;
        align-items: center;
        gap: 15px;
    }
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}