/* ==========================================================================
   Academic Personal Website - Prakash Mishra
   Clean, minimal design inspired by academic themes
   ========================================================================== */

/* --------------------------------------------------------------------------
   CSS Variables - Color Scheme
   -------------------------------------------------------------------------- */
:root {
    /* Emphasis - Caltech orange. #FF6C0C is ~2.8:1 on white, below WCAG AA
       for text of any size, so use it only for non-text emphasis (rules,
       underlines, hover fills behind dark text). Text that should read as
       orange uses --color-accent, the same hue darkened to pass AA. */
    --color-emphasis: #FF6C0C;

    /* Primary Colors - forest green */
    --color-primary: #1E3A2F;
    --color-primary-light: #2F5444;
    --color-primary-dark: #13261F;

    /* Accent Colors - orange ink for text (~5:1 on white) */
    --color-accent: #B84D09;
    --color-accent-light: #FF6C0C;

    /* Neutral Colors - green-tinted grays on warm stone */
    --color-text: #2A332E;
    --color-text-light: #445A50;
    --color-text-muted: #5F6E67;
    --color-background: #FFFFFF;
    --color-background-alt: #F8F7F2;
    --color-border: #E3E0D5;

    /* Typography */
    --font-sans: 'Source Sans Pro', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-serif: 'Source Serif Pro', Georgia, 'Times New Roman', serif;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;

    /* Layout */
    --max-width: 900px;
    --nav-height: 60px;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: var(--nav-height);
}

body {
    margin: 0;
    padding: 0;
    font-family: var(--font-sans);
    font-size: 16px;
    line-height: 1.7;
    color: var(--color-text);
    background-color: var(--color-background);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-serif);
    font-weight: 600;
    line-height: 1.3;
    color: var(--color-primary);
    margin-top: 0;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 1.875rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }

p {
    margin-top: 0;
    margin-bottom: var(--spacing-md);
}

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

a:hover {
    color: var(--color-primary);
    text-decoration: underline;
    text-decoration-color: var(--color-emphasis);
    text-decoration-thickness: 2px;
    text-underline-offset: 3px;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

ul {
    padding-left: var(--spacing-lg);
}

/* --------------------------------------------------------------------------
   Layout
   -------------------------------------------------------------------------- */
.container {
    width: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.section {
    padding: var(--spacing-3xl) 0;
}

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

/* --------------------------------------------------------------------------
   Navigation
   -------------------------------------------------------------------------- */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--nav-height);
    background-color: var(--color-background);
    border-bottom: 1px solid var(--color-border);
    z-index: 1000;
    transition: box-shadow var(--transition-base);
}

.navbar.scrolled {
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.nav-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    font-family: var(--font-serif);
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-primary);
    text-decoration: none;
}

.nav-logo:hover {
    color: var(--color-primary-light);
    text-decoration: none;
}

.nav-menu {
    display: flex;
    list-style: none;
    margin: 0;
    padding: 0;
    gap: var(--spacing-xl);
}

.nav-link {
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--color-text-light);
    text-decoration: none;
    padding: var(--spacing-sm) 0;
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--color-emphasis);
    transition: width var(--transition-base);
}

.nav-link:hover,
.nav-link.active {
    color: var(--color-primary);
    text-decoration: none;
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

/* Mobile Navigation Toggle */
.nav-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-sm);
}

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

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

.hamburger::before {
    top: -7px;
}

.hamburger::after {
    top: 7px;
}

/* --------------------------------------------------------------------------
   Hero / About Section
   -------------------------------------------------------------------------- */
.hero {
    margin-top: var(--nav-height);
    padding-top: var(--spacing-3xl);
}

.hero-content {
    display: grid;
    grid-template-columns: 200px 1fr;
    gap: var(--spacing-2xl);
    align-items: start;
}

.hero-image {
    position: sticky;
    top: calc(var(--nav-height) + var(--spacing-xl));
}

.profile-photo {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    object-fit: cover;
    border: 4px solid var(--color-border);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.hero-text h1 {
    margin-bottom: var(--spacing-sm);
}

.hero-text .title {
    font-size: 1.125rem;
    color: var(--color-accent);
    margin-bottom: var(--spacing-xs);
    font-weight: 500;
}

.hero-text .affiliation {
    font-size: 1rem;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-md);
}

.hero-text .future-position {
    font-size: 0.9375rem;
    color: var(--color-text-light);
    background-color: var(--color-background-alt);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: 4px;
    margin-bottom: var(--spacing-lg);
    border-left: 3px solid var(--color-emphasis);
}

.bio {
    margin-bottom: var(--spacing-lg);
}

.bio p:last-child {
    margin-bottom: 0;
}

.social-links {
    display: flex;
    gap: var(--spacing-md);
}

.social-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background-color: var(--color-background-alt);
    color: var(--color-text-light);
    transition: all var(--transition-fast);
}

.social-link:hover {
    background-color: var(--color-emphasis);
    color: var(--color-primary);
    text-decoration: none;
}

/* --------------------------------------------------------------------------
   Research Section
   -------------------------------------------------------------------------- */
.section-title {
    position: relative;
    margin-bottom: var(--spacing-2xl);
    padding-bottom: var(--spacing-md);
    border-bottom: 2px solid var(--color-border);
}

.section-title::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: -2px;
    width: 3rem;
    height: 2px;
    background-color: var(--color-emphasis);
}

.research-category {
    margin-bottom: var(--spacing-2xl);
}

.research-category:last-child {
    margin-bottom: 0;
}

.category-title {
    font-size: 1.125rem;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--spacing-lg);
    font-family: var(--font-sans);
    font-weight: 600;
}

.paper {
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-xl);
    border-bottom: 1px solid var(--color-border);
}

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

.paper-title {
    font-size: 1.125rem;
    margin-bottom: var(--spacing-sm);
    color: var(--color-primary);
}

.paper-authors {
    font-size: 0.9375rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-sm);
    font-style: italic;
}

.paper-status {
    font-size: 0.875rem;
    color: var(--color-accent);
    margin-bottom: var(--spacing-sm);
    font-weight: 500;
}

.paper-links {
    margin-bottom: var(--spacing-sm);
}

.paper-links a {
    font-size: 0.875rem;
    font-weight: 500;
    margin-right: var(--spacing-md);
}

.paper-media {
    font-size: 0.8125rem;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-sm);
}

/* Works in Progress */
.works-in-progress {
    list-style: none;
    padding-left: 0;
}

.works-in-progress li {
    padding: var(--spacing-md) 0;
    border-bottom: 1px solid var(--color-border);
}

.works-in-progress li:last-child {
    border-bottom: none;
}

.wip-title {
    display: block;
    font-weight: 500;
    color: var(--color-text);
    margin-bottom: var(--spacing-xs);
}

.wip-authors {
    display: block;
    font-size: 0.875rem;
    color: var(--color-text-muted);
    font-style: italic;
}

/* --------------------------------------------------------------------------
   Teaching Section
   -------------------------------------------------------------------------- */
.teaching-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xl);
}

.course {
    padding: var(--spacing-lg);
    background-color: var(--color-background);
    border-radius: 8px;
    border: 1px solid var(--color-border);
}

.course-title {
    margin-bottom: var(--spacing-sm);
    color: var(--color-primary);
}

.course-info {
    font-size: 0.9375rem;
    color: var(--color-accent);
    margin-bottom: var(--spacing-xs);
    font-weight: 500;
}

.course-instructor {
    font-size: 0.875rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-xs);
}

.course-institution {
    font-size: 0.875rem;
    color: var(--color-text-muted);
    margin-bottom: 0;
}

/* --------------------------------------------------------------------------
   CV Section
   -------------------------------------------------------------------------- */
.cv-content {
    text-align: center;
    padding: var(--spacing-xl);
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: 1rem;
    font-weight: 600;
    text-decoration: none;
    border-radius: 6px;
    transition: all var(--transition-fast);
    cursor: pointer;
}

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

.btn-primary:hover {
    background-color: var(--color-emphasis);
    border-color: var(--color-emphasis);
    color: var(--color-primary);
    text-decoration: none;
}

/* --------------------------------------------------------------------------
   Contact Section
   -------------------------------------------------------------------------- */
.contact-content {
    max-width: 600px;
    margin: 0 auto;
}

.contact-info {
    display: grid;
    gap: var(--spacing-xl);
}

.contact-item h4 {
    font-family: var(--font-sans);
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-sm);
}

.contact-item p,
.contact-item a {
    font-size: 1rem;
    line-height: 1.6;
    margin-bottom: 0;
}

/* --------------------------------------------------------------------------
   Footer
   -------------------------------------------------------------------------- */
.footer {
    padding: var(--spacing-xl) 0;
    text-align: center;
    border-top: 1px solid var(--color-border);
    background-color: var(--color-background);
}

.footer p {
    margin-bottom: 0;
    font-size: 0.875rem;
    color: var(--color-text-muted);
}

/* --------------------------------------------------------------------------
   Responsive Design
   -------------------------------------------------------------------------- */
@media (max-width: 768px) {
    :root {
        --nav-height: 56px;
    }

    h1 { font-size: 2rem; }
    h2 { font-size: 1.5rem; }

    .section {
        padding: var(--spacing-2xl) 0;
    }

    /* Mobile Navigation */
    .nav-toggle {
        display: block;
    }

    .nav-menu {
        position: fixed;
        top: var(--nav-height);
        left: 0;
        right: 0;
        background-color: var(--color-background);
        flex-direction: column;
        padding: var(--spacing-lg);
        gap: 0;
        border-bottom: 1px solid var(--color-border);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all var(--transition-base);
    }

    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .nav-link {
        padding: var(--spacing-md) 0;
        border-bottom: 1px solid var(--color-border);
    }

    .nav-link:last-child {
        border-bottom: none;
    }

    /* Hamburger Animation */
    .nav-toggle.active .hamburger {
        background-color: transparent;
    }

    .nav-toggle.active .hamburger::before {
        transform: rotate(45deg) translate(5px, 5px);
    }

    .nav-toggle.active .hamburger::after {
        transform: rotate(-45deg) translate(5px, -5px);
    }

    /* Hero Section */
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-image {
        position: static;
        display: flex;
        justify-content: center;
    }

    .profile-photo {
        width: 160px;
        height: 160px;
    }

    .hero-text .future-position {
        text-align: left;
    }

    .bio {
        text-align: left;
    }

    .social-links {
        justify-content: center;
    }

    /* Contact Section */
    .contact-info {
        text-align: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--spacing-md);
    }

    h1 { font-size: 1.75rem; }

    .profile-photo {
        width: 140px;
        height: 140px;
    }

    .btn {
        width: 100%;
        justify-content: center;
    }
}

/* --------------------------------------------------------------------------
   Print Styles
   -------------------------------------------------------------------------- */
@media print {
    .navbar,
    .social-links,
    .btn {
        display: none;
    }

    .section {
        padding: var(--spacing-lg) 0;
        page-break-inside: avoid;
    }

    .hero {
        margin-top: 0;
    }

    body {
        font-size: 12pt;
    }
}