:root {
    --bg-main: #161b22;
    --bg-panel: rgba(20,24,31,0.88);
    --text-main: #f5f6fa;
    --nav-bg: rgba(22,27,34,0.85);
    --nav-link: #58a6ff;
    --nav-link-hover: #f5f6fa;
    --footer-bg: rgba(22,27,34,0.95);
    --panel-radius: 1rem;
    --panel-shadow: none;
    --bg-img: url('/images/bg_dark.jpeg');
}

body.light-mode {
    --bg-main: #f6f8fa;
    --bg-panel: rgba(255,255,255,0.96);
    --text-main: #23272f;
    --nav-bg: rgba(255,255,255,0.97);
    --nav-link: #2962ff;
    --nav-link-hover: #222;
    --footer-bg: rgba(255,255,255,0.98);
    --panel-shadow: 0 4px 32px 0 rgba(200,200,200,0.08);
    --bg-img: url('/images/bg_light.jpeg');
}

html, body {
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', Arial, sans-serif;
    background: var(--bg-main);
    color: var(--text-main);
    transition: background 0.25s, color 0.2s;
    font-size: 16px;
    height: 100%;
}

body {
    min-height: 100vh;
    position: relative;
}

.bg-image {
    background: var(--bg-img) no-repeat center center fixed;
    background-size: cover;
    opacity: 0.5;
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: 0;
    pointer-events: none;
    transition: background 0.4s;
}

.main-content {
    position: relative;
    z-index: 2;
    padding-top: 80px; /* height of nav */
    padding-bottom: 60px; /* height of footer */
}

nav {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    background: var(--nav-bg);
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    padding: 1rem 0.5rem;
    gap: 0.7rem;
}

nav a {
    color: var(--nav-link);
    text-decoration: none;
    margin: 0 0.7rem;
    font-weight: 600;
    font-size: 1rem;
    border-radius: 0.4em;
    padding: 0.18em 0.4em;
}

nav a:hover, nav a:focus {
    color: var(--nav-link-hover);
    text-decoration: underline;
    background: rgba(50,50,70,0.07);
}

#mode-toggle {
    margin-left: 1rem;
    font-size: 1.3rem;
    background: none;
    border: none;
    color: var(--nav-link);
    cursor: pointer;
    outline: none;
    border-radius: 0.3em;
    padding: 0.18em 0.4em;
    transition: color 0.2s, background 0.2s;
}

#mode-toggle:focus, #mode-toggle:hover {
    color: var(--nav-link-hover);
    background: rgba(50,50,70,0.09);
}

section {
    padding: 2.2rem 1rem;
    max-width: 800px;
    margin: 2rem auto;
    background: var(--bg-panel);
    border-radius: var(--panel-radius);
    box-shadow: var(--panel-shadow);
    transition: background 0.3s, color 0.2s;
    word-break: break-word;
}

h1, h2 {
    text-align: center;
    margin-top: 0;
    word-break: break-word;
}

ul {
    line-height: 1.6;
    padding-left: 1.3rem;
    font-size: 1rem;
}

footer {
    position: fixed;
    bottom: 0;
    width: 100%;
    background: var(--footer-bg);
    color: white;
    text-align: center;
    padding: 0.7rem 0;
    font-size: 0.9rem;
    z-index: 999;
    transition: background 0.3s, color 0.2s;
}

/* Transition helpers */
body, section, nav, footer {
    transition: background 0.3s, color 0.2s;
}

/* Burger Menu Styles */
#burger {
    display: none;
    background: none;
    border: none;
    padding: 0.5em 0.8em;
    cursor: pointer;
    margin-right: 0.5em;
    outline: none;
    z-index: 100;
}
.burger-lines {
    width: 1.7em;
    height: 0.18em;
    background: var(--nav-link);
    display: block;
    position: relative;
    border-radius: 0.13em;
    transition: background 0.2s;
}
.burger-lines::before, .burger-lines::after {
    content: "";
    display: block;
    width: 1.7em;
    height: 0.18em;
    background: var(--nav-link);
    position: absolute;
    left: 0;
    border-radius: 0.13em;
    transition: transform 0.3s, top 0.3s, opacity 0.3s;
}
.burger-lines::before {
    top: -0.5em;
}
.burger-lines::after {
    top: 0.5em;
}
#burger.open .burger-lines {
    background: transparent;
}
#burger.open .burger-lines::before {
    transform: rotate(45deg);
    top: 0;
}
#burger.open .burger-lines::after {
    transform: rotate(-45deg);
    top: 0;
}

/* Main nav links container */
.nav-links {
    display: flex;
    flex-direction: row;
    align-items: center;
    gap: 0.7rem;
}

/* Mobile Responsiveness */
@media (max-width: 600px) {
    html, body {
        font-size: 15px;
    }
    nav {
        justify-content: flex-start;
        flex-direction: column;
        align-items: stretch;
        padding: 0.7rem 0.3rem;
        gap: 0;
    }
    #burger {
        display: block;
        z-index: 200;
    }
    .nav-links {
        flex-direction: column;
        align-items: stretch;
        position: absolute;
        top: 110%;
        left: 0;
        width: 98vw;
        background: var(--nav-bg);
        box-shadow: 0 6px 32px 0 rgba(16, 30, 54, 0.18);
        border-radius: 0 0 1.1em 1.1em;
        padding: 1em 0.6em 0.8em 0.6em;
        opacity: 0;
        pointer-events: none;
        transform: translateY(-20px) scale(0.95);
        transition: opacity 0.22s, transform 0.22s;
        gap: 0.15rem;
    }
    .nav-links.show {
        opacity: 1;
        pointer-events: auto;
        transform: translateY(0) scale(1);
    }
    .nav-links a, .nav-links #mode-toggle {
        margin: 0.2rem 0;
        font-size: 1.08rem;
        padding: 0.4em 0.7em;
        border-radius: 0.5em;
    }
    section {
        padding: 1rem;
        margin: 1rem 0.5rem;
        border-radius: 0.7rem;
    }
    footer {
        font-size: 0.95rem;
        padding: 0.6rem 0.2rem;
    }
}

@media (max-width: 370px) {
    section {
        padding: 0.5rem 0.3rem;
    }
    nav a, #mode-toggle {
        font-size: 0.95rem;
        padding: 0.2em 0.4em;
    }
}
/* 3D perspective container */
#rolodex {
  perspective: 1200px;            /* depth of the view */
  transform-style: preserve-3d;   /* keep children in 3D space */
  overflow-x: hidden;
}

/* Base style for each panel */
#rolodex section {
  transform-origin: center center -200px; /* pivot slightly behind the screen */
  will-change: transform;                 /* hint for GPU acceleration */
  transition: transform 0.2s ease-out;    /* smooth out micro-flips */
}

/* Optional: add a little lighting effect */
#rolodex section::before {
  content: "";
  position: absolute;
  top: 0; right: 0; bottom: 0; left: 0;
  pointer-events: none;
  background: linear-gradient(to bottom, rgba(0,0,0,0.05), rgba(0,0,0,0.15));
  opacity: 0;
  transition: opacity 0.2s ease-out;
}
#rolodex section.flipped::before {
  opacity: 1;
}
/* drum-container clips overflow and provides perspective */
#drum-container {
  position: relative;
  height: 100vh;            /* one full viewport of panels */
  overflow: hidden;
  perspective: 1200px;
}

/* the 3D cylinder */
#drum {
  position: absolute;
  top: 50%;
  left: 50%;
  transform-style: preserve-3d;
  transform-origin: center center;
  /* we'll set initial rotation & translateZ in JS */
}

/* panels become faces of the cylinder */
#drum section {
  position: absolute;
  width: 80vw;              /* adjust width as needed */
  max-width: 600px;
  left: 50%;
  top: 50%;
  transform-origin: center center;
  margin: 0;
  padding: 2rem;
  background: rgba(255,255,255,0.8);
  box-shadow: 0 5px 15px rgba(0,0,0,0.2);
  border-radius: 8px;
}
/* Carousel wrapper */
.carousel {
  position: relative;
  overflow: hidden;
  margin: 1rem 0;
}

/* Slides container as a flex row */
.slides {
  display: flex;
  transition: transform 0.4s ease;
}

/* Each slide takes full width of section */
.slide {
  min-width: 100%;
  box-sizing: border-box;
  padding: 1rem;
}

/* Hide overflow on single-slide fallback */
.single-slide {
  padding: 1rem;
}

/* Arrows */
.carousel-arrow {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  background: rgba(255,255,255,0.8);
  border: none;
  font-size: 2rem;
  cursor: pointer;
  padding: 0 0.5rem;
  transition: background 0.2s;
  user-select: none;
}
.carousel-arrow:hover {
  background: rgba(255,255,255,1);
}
.carousel-arrow.prev { left: 0.5rem; }
.carousel-arrow.next { right: 0.5rem; }

/* Dots */
.carousel-dots {
  display: flex;
  justify-content: center;
  margin-top: 0.5rem;
}
.dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: #bbb;
  margin: 0 4px;
  cursor: pointer;
  transition: background 0.2s;
}
.dot:hover { background: #888; }
.dot.active { background: #333; }