:root {
	--grey: rgb(90, 90, 90);
    --black:  rgb(0, 0, 0);
	/* Columbia Blues: https://visualidentity.columbia.edu/content/colors-1 */
	--blue1: rgb(2,33,105);
	--blue2: rgb(0,51,160);
	--blue3: rgb(0,114,206);
	--blue4: rgb(108,172,228);
    --blue5: rgb(23, 116, 210);
	--pink1: #F9564F;
 }

html, p{
    margin: 0;
    padding: 0;
    border: 0;
    font-size: 100%;
    font: inherit;
    vertical-align: baseline;
    font-family: 'Source Sans Pro', sans-serif;
    /*font-family: "Helvetica Neue","Helvetica","Arial",sans-serif;;*/
    font-weight: 300;
    letter-spacing: 0.5px;
    color: var(--black);
}
p{
    margin: 0.2em;
}

ol, ul {
    list-style: none;
}

ul {
    /*list-style-position: inside;*/
    list-style-position: outside;
    list-style-type: disc;
}

a {
    text-decoration: none;
    font-weight: 500;
    color:  var(--blue5);
}

i {
    font-style: italic;
}

h1 {
    font-weight: 500;
    color: var(--black);
}

b {
    font-weight: 500;
}

/**************************************************/

#header {
    height: 2em;
    line-height: 2em;
    padding-top: 10px;
    padding-bottom: 10px;
    border-bottom: 1px solid #ddd;
    position: fixed;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    z-index: 9999;
    width: 1000px;
    background-color: rgba(255, 255, 255, 0.7);
    backdrop-filter: blur(8px);
}

#header a {
    text-decoration: none;
    color: var(--black);
    font-weight: 400;
    font-size: 18px;
    transition: color 0.3s ease;
}

#header a:hover {
    color: var(--pink1);
}

/**************************************************/

#profile {
    padding: 4.5rem 0 0 0;
    margin-bottom: 0;
    margin-top: 1rem;
}

.profile-container {
    display: flex;
    align-items: flex-start;
    gap: 2rem;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

.profile-image-container {
    flex-shrink: 0;
}

.profile-image {
    width: 250px;
    height: 250px;
    border-radius: 50%;
    object-fit: cover;
    border: 3px solid var(--accent-color);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.profile-content {
    flex-grow: 1;
}

.profile-name {
    font-size: 2.5rem;
    font-weight: 700;
    margin: 0 0 0.5rem 0;
    color: var(--text-color);
}

.profile-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--accent-color);
    margin-bottom: 0;
}

.profile-affiliations {
    margin-bottom: 1rem;
    line-height: 1.6;
    font-size: 1rem;
}

.profile-affiliations div {
    color: var(--text-color);
    font-size: 1rem;
}

.profile-university a {
    color: var(--accent-color);
    text-decoration: none;
    transition: color 0.2s ease;
}

.profile-university a:hover {
    color: var(--accent-hover);
}

.profile-bio {
    margin-bottom: 1.5rem;
    line-height: 1.6;
    color: var(--text-color);
}

.profile-bio a {
    color: var(--accent-color);
    text-decoration: none;
    transition: color 0.2s ease;
}

.profile-bio a:hover {
    color: var(--accent-hover);
}

.profile-links {
    display: flex;
    gap: 1rem;
    margin-top: 1rem;
}

.profile-link-icon {
    color: var(--text-color);
    transition: all 0.2s ease;
    padding: 0.5rem;
    border-radius: 50%;
    background: var(--bg-secondary);
}

.profile-link-icon:hover {
    color: var(--accent-color);
    transform: translateY(-2px);
    background: var(--bg-hover);
}

.profile-link-icon svg {
    width: 20px;
    height: 20px;
}

/* Research Focus Section */
#research-focus {
    padding: 0;
    background: transparent;
}

.research-focus-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0;
    text-align: left;
    margin-bottom: 2rem;
    width: 100%;
}

.research-focus-text {
    font-size: 1rem;
    line-height: 1.6;
    color: var(--text-color);
    max-width: 100%;
    margin: 0;
    font-family: 'Source Sans Pro', sans-serif;
    font-weight: 300;
    letter-spacing: 0.5px;
    text-align: left;
    padding: 0;
}

/* Research Tabs Styles */
.research-tabs-container {
    max-width: 1200px;
    margin: 2rem auto 0;
    padding: 0;
    background: transparent;
    box-shadow: none;
    overflow: visible;
}

.research-tabs {
    display: flex;
    border-bottom: 1px solid #e5e7eb;
    background: transparent;
    margin-bottom: 1rem;
}

.research-tab {
    display: flex;
    align-items: center;
    padding: 0.75rem 1.25rem;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1.1rem;
    font-weight: 500;
    color: #6b7280;
    transition: all 0.2s ease;
    position: relative;
    border: none;
}

.research-tab:hover {
    color: #111827;
    background-color: transparent;
}

.research-tab.active {
    color: var(--blue5);
    font-weight: 600;
}

.research-tab.active::after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: var(--blue5);
}

.theme-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    margin-right: 0.5rem;
}

.theme-icon svg {
    width: 20px;
    height: 20px;
    stroke: currentColor;
}

.research-tab:hover .theme-icon svg {
    stroke: var(--blue5);
}

.research-tab.active .theme-icon svg {
    stroke: var(--blue5);
}

.theme-title {
    font-weight: inherit;
}

.research-tab-content {
    padding: 1rem 0;
    position: relative;
    width: 100%;
}

.tab-pane {
    display: none;
    padding: 0;
    width: 100%;
}

.tab-pane.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

.tab-pane p {
    font-size: 1rem;
    line-height: 1.6;
    color: #374151;
    margin: 0;
    max-width: 100%;
    width: 100%;
}

@media (max-width: 768px) {
    .research-tabs {
        flex-wrap: wrap;
        gap: 0.5rem;
    }
    
    .research-tab {
        flex: 1 1 auto;
        padding: 0.5rem 1rem;
        justify-content: center;
        text-align: center;
        font-size: 1rem;
    }
    
    .research-tab.active::after {
        bottom: 0;
    }
}

.divider {
    width: 100%;
    border-bottom: 1px solid #ddd;
}

.research-thumb {
    width: 8em;
    height: 8em;
    float: left;
    margin-top: 0px;
    padding-right: 30px;
    margin-bottom: 20px;
}

.research-thumb img {
    width: 100%;
}

.research-proj-title {
    color: var(--black);
    font-weight: 400;
    font-size: 18px;
}

.press-thumb {
    width: 4em;
    height: 4em;
    float: left;
    margin-top: 0px;
    padding-right: 30px;
    margin-bottom: 30px;
}

.press-thumb img {
    width: 100%;
}

.press-title {
    color: var(--black);
    font-weight: 400;
    font-size: 16px;
}

.paper-award {
    color: red;
	font-weight: 500;
}

.hvr-grow {
    display: inline-block;
    vertical-align: middle;
    transform: translateZ(0);
    box-shadow: 0 0 1px rgba(0, 0, 0, 0);
    backface-visibility: hidden;
    -moz-osx-font-smoothing: grayscale;
    transition-duration: 0.3s;
    transition-property: transform;
}

.hvr-grow:hover,
.hvr-grow:focus,
.hvr-grow:active {
    transform: scale(1.05);
}

div.gallery img {
  width: 100%;
  height: auto;
  border-radius: 2.5%;
}

.responsive {
  padding: 2px;
  float: left;
  width: 24.99999%;
  box-sizing: border-box;
}

.load-more-button {
    background-color: transparent;
    color: var(--black);
    border: 2px solid var(--black);
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.2s ease;
    font-family: 'Source Sans Pro', sans-serif;
    font-weight: 500;
    margin: 2rem 0;
    width: auto;
}

.load-more-button:hover {
    background-color: var(--black);
    color: white;
    border: 2px solid var(--black);
    transform: translateY(-2px);
}

/*footer*/
footer {
    position: relative;
    height: 50px;
    width: 100%;
    background-color: var(--white);
}

p.copyright {
    position: absolute;
    width: 100%;
    color: var(--black);
    line-height: 40px;
    font-size: 1em;
    text-align: center;
    bottom:0;
}

/* Research Themes Styles */

.research-focus-text {
    /* color: var(--grey); */
    margin-bottom: 8px;
    /* line-height: 1.5; */
}

.font-bold {
    font-weight: 600;
}

.text-blue {
    color: var(--blue5);
    font-weight: 500;
}

.text-green {
    color: #10B981;
    font-weight: 500;
}

.text-purple {
    color: #8B5CF6;
    font-weight: 500;
}

.text-black {
    color: #000000;
    font-weight: 500;
}

.research-themes-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
    margin-bottom: 20px;
}

@media (min-width: 768px) {
    .research-themes-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

.research-theme-card {
    background-color: white;
    border-radius: 8px;
    padding: 12px;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
    transition: box-shadow 0.3s ease;
    cursor: pointer;
    position: relative;
}

.research-theme-card:hover {
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.theme-header {
    display: flex;
    align-items: center;
    margin-bottom: 4px;
}

.theme-title {
    font-size: 16px;
    font-weight: 600;
    color: var(--black);
    margin: 0;
}

.theme-description {
    font-size: 12px;
    color: var(--grey);
    margin: 0;
    display: none;
    position: absolute;
    background-color: white;
    padding: 8px;
    border-radius: 4px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    z-index: 10;
    width: 100%;
    left: 0;
    top: 100%;
}

.research-theme-card:hover .theme-description {
    display: block;
}

/* Sponsor Acknowledgments */
.acknowledgments-section {
    margin: 0 0 45px 0;  /* Increased top margin to 200px for more space */
    padding: 0 0;
    text-align: left;
    max-width: 1000px;
    margin-left: auto;
    margin-right: auto;
}

.acknowledgments-section h2 {
    font-size: 1.8em;
    margin-bottom: 15px;
    color: var(--black);
}

.acknowledgments-section p {
    margin-bottom: 25px;
    font-size: 1.1em;
}

.sponsors-container {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 40px;
    margin: 45px 0;
    max-width: 1000px;
    min-width: 800px;  /* Ensure minimum width to maintain layout */
    margin-left: auto;
    margin-right: auto;
}

.sponsor-item {
    width: calc(20% - 32px);  /* 5 items per row with gap consideration */
    min-width: 120px;
    height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: transform 0.3s ease;
}

.sponsor-item img {
    max-width: 80%;
    max-height: 80%;
    object-fit: contain;
}

/* Specific style for BMW logo to make it smaller */
.sponsor-item img[alt="BMW"] {
    max-width: 55%;
    max-height: 55%;
}

.sponsor-text {
    font-size: 0.9em;
    color: var(--grey);
    max-width: 800px;
    margin: 30px auto 0;
    line-height: 1.5;
}