/* ===== Base Styles ===== */
:root {
    --color-primary: #1a237e;
    --color-secondary: #283593;
    --color-accent: #ffb300;
    --color-text: #333;
    --color-text-light: #666;
    --color-bg: #fff;
    --color-bg-secondary: #f8f9fa;
    --color-border: #e0e0e0;
    --font-serif: 'Lora', Georgia, serif;
    --font-sans: 'Open Sans', Helvetica, Arial, sans-serif;
    --spacing-unit: 1rem;
    --max-width: 1200px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-serif);
    font-size: 18px;
    line-height: 1.7;
    color: var(--color-text);
    background-color: var(--color-bg);
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-unit);
}

/* ===== Typography ===== */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-sans);
    font-weight: 600;
    line-height: 1.3;
    margin-bottom: calc(var(--spacing-unit) * 0.5);
    color: var(--color-primary);
}

h1 { font-size: 2.2rem; }
h2 { font-size: 1.8rem; border-bottom: 2px solid var(--color-accent); padding-bottom: 0.5rem; }
h3 { font-size: 1.4rem; }

p {
    margin-bottom: var(--spacing-unit);
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color 0.2s ease;
}

a:hover {
    color: var(--color-accent);
    text-decoration: underline;
}

em {
    font-style: italic;
}

strong {
    font-weight: 600;
}

/* ===== Header ===== */
.header {
    background-color: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-unit) 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-unit);
}

.site-title {
    font-size: 1.5rem;
    font-weight: 700;
}

.site-title a {
    color: var(--color-primary);
}

.site-title a:hover {
    text-decoration: none;
}

/* ===== Navigation ===== */
.main-nav {
    display: flex;
    align-items: center;
}

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

.nav-list a {
    font-family: var(--font-sans);
    font-size: 0.95rem;
    font-weight: 500;
    padding: 0.5rem 0;
    position: relative;
}

.nav-list a.active {
    color: var(--color-accent);
}

.nav-list a.active::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 2px;
    background-color: var(--color-accent);
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.hamburger {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--color-primary);
    position: relative;
}

.hamburger::before,
.hamburger::after {
    content: '';
    position: absolute;
    width: 24px;
    height: 2px;
    background-color: var(--color-primary);
    left: 0;
}

.hamburger::before { top: -8px; }
.hamburger::after { top: 8px; }

/* ===== Main Content ===== */
.main-content {
    padding: calc(var(--spacing-unit) * 2) 0;
}

/* ===== Layout: Sidebar + Content ===== */
.container {
    display: grid;
    grid-template-columns: 280px 1fr;
    gap: calc(var(--spacing-unit) * 2);
}

.sidebar {
    position: sticky;
    top: 80px;
    height: fit-content;
    align-self: start;
}

.sidebar-nav {
    background-color: var(--color-bg-secondary);
    padding: var(--spacing-unit);
    border-radius: 4px;
    border: 1px solid var(--color-border);
}

.sidebar-title {
    font-family: var(--font-sans);
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: var(--spacing-unit);
    color: var(--color-primary);
    border-bottom: 1px solid var(--color-border);
    padding-bottom: 0.5rem;
}

.sidebar-list {
    list-style: none;
}

.sidebar-list li {
    margin-bottom: 0.5rem;
}

.sidebar-list a {
    font-size: 0.95rem;
    display: block;
    padding: 0.3rem 0;
}

.sidebar-list a:hover {
    color: var(--color-accent);
}

.content-area {
    min-width: 0;
}

.content-section {
    margin-bottom: calc(var(--spacing-unit) * 3);
    padding-bottom: calc(var(--spacing-unit) * 2);
    border-bottom: 1px solid var(--color-border);
}

.content-section:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

/* ===== Bibliography ===== */
.bibliography {
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.bib-section {
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.bib-section h3 {
    font-size: 1.3rem;
    margin-bottom: var(--spacing-unit);
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--color-border);
}

.bib-entry {
    margin-bottom: 1.2rem;
    padding-left: 1rem;
    border-left: 3px solid var(--color-accent);
}

.bib-entry p {
    margin-bottom: 0.5rem;
    font-size: 0.95rem;
}

.bib-links {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    margin-top: 0.5rem;
}

.bib-links a {
    font-size: 0.85rem;
    font-family: var(--font-sans);
}

.bib-links .scholar {
    color: #4285f4;
}

.bib-links .publisher {
    color: var(--color-primary);
}

.bib-links .url {
    color: #006621;
}

.bib-note {
    background-color: #fff8e1;
    padding: 1rem;
    border-left: 4px solid #ffb300;
    margin-bottom: 2rem;
    font-size: 0.95rem;
}

.bib-note p {
    margin-bottom: 0;
}
/* ===== Publications ===== */
.publication-list {
    list-style: none;
}

.publication-item {
    margin-bottom: calc(var(--spacing-unit) * 2);
    padding-bottom: calc(var(--spacing-unit) * 1.5);
    border-bottom: 1px solid var(--color-border);
}

.publication-item:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.publication-meta {
    font-family: var(--font-sans);
    font-size: 0.9rem;
    color: var(--color-text-light);
    margin-bottom: 0.5rem;
}

.publication-title {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
}

.publication-links {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

/* ===== Footer ===== */
.footer {
    background-color: var(--color-bg-secondary);
    padding: calc(var(--spacing-unit) * 2) 0;
    border-top: 1px solid var(--color-border);
    margin-top: calc(var(--spacing-unit) * 3);
}

.footer p {
    text-align: center;
    font-family: var(--font-sans);
    font-size: 0.9rem;
    color: var(--color-text-light);
}

/* ===== Responsive Design ===== */
@media (max-width: 900px) {
    .container {
        grid-template-columns: 1fr;
    }

    .sidebar {
        position: static;
        margin-bottom: var(--spacing-unit);
    }

    .header .container {
        flex-direction: column;
        align-items: flex-start;
    }

    .mobile-menu-toggle {
        display: block;
    }

    .nav-list {
        display: none;
        flex-direction: column;
        width: 100%;
        margin-top: var(--spacing-unit);
    }

    .nav-list.active {
        display: flex;
    }

    .nav-list li {
        padding: 0.5rem 0;
        border-bottom: 1px solid var(--color-border);
    }

    .content-section {
        padding-bottom: var(--spacing-unit);
    }
}

@media (max-width: 600px) {
    h1 { font-size: 1.8rem; }
    h2 { font-size: 1.5rem; }
    h3 { font-size: 1.2rem; }

    body {
        font-size: 16px;
        line-height: 1.6;
    }

    .header {
        padding: calc(var(--spacing-unit) * 0.5) 0;
    }

    .main-content {
        padding: var(--spacing-unit) 0;
    }
}

/* ===== Print Styles ===== */
@media print {
    .header, .footer, .mobile-menu-toggle {
        display: none;
    }

    .container {
        display: block;
    }

    .sidebar {
        display: none;
    }

    a {
        color: var(--color-primary);
        text-decoration: underline;
    }

    .content-section {
        page-break-inside: avoid;
    }
}

/* ===== Utility Classes ===== */
.text-center {
    text-align: center;
}

.mt-2 { margin-top: calc(var(--spacing-unit) * 2); }
.mb-2 { margin-bottom: calc(var(--spacing-unit) * 2); }

.btn {
    display: inline-block;
    background-color: var(--color-primary);
    color: white;
    padding: 0.75rem 1.5rem;
    border-radius: 4px;
    font-family: var(--font-sans);
    font-size: 0.95rem;
    font-weight: 600;
    transition: background-color 0.2s ease;
}

.btn:hover {
    background-color: var(--color-secondary);
    color: white;
    text-decoration: none;
}

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

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