:root {
    --bg-dark: #000000;
    --text-primary: #ffffff;
    --text-muted: rgba(255, 255, 255, 0.6);
    --accent: #f59e0b;
    --font-main: 'Outfit', sans-serif;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

html, body {
    width: 100%;
    height: 100%;
    overflow: hidden;
    background-color: var(--bg-dark);
    font-family: var(--font-main);
    color: var(--text-primary);
}

/* --- Vertical Scroller --- */
.vertical-scroller {
    width: 100%;
    height: 100%;
    overflow-y: scroll;
    scroll-snap-type: y mandatory;
    scrollbar-width: none; /* Firefox */
    -ms-overflow-style: none; /* IE 10+ */
}

.vertical-scroller::-webkit-scrollbar {
    display: none; /* Chrome/Safari */
}

.video-section {
    width: 100%;
    height: 100vh;
    scroll-snap-align: start;
    position: relative;
    overflow: hidden;
}

.video-container {
    width: 100%;
    height: 100%;
    background: #000;
}

.video-container video {
    width: 100%;
    height: 100%;
    object-fit: cover; /* Cinematic full-screen crop */
}

/* --- Minimal UI Overlays --- */
.ui-overlay {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    padding: 40px;
    background: linear-gradient(to top, rgba(0,0,0,0.8) 0%, transparent 100%);
    pointer-events: none;
    display: flex;
    flex-direction: column;
    gap: 8px;
    transition: opacity 0.5s;
}

.technique-label {
    font-size: 0.8rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 2px;
    color: var(--accent);
}

.lesson-title {
    font-size: 2rem;
    font-weight: 600;
    line-height: 1.1;
}

.instruction-hint {
    font-size: 1rem;
    color: var(--text-muted);
    max-width: 80%;
}

/* --- Interaction Utilities --- */
.mute-toggle {
    position: absolute;
    top: 40px;
    right: 40px;
    width: 44px;
    height: 44px;
    background: rgba(255,255,255,0.1);
    backdrop-filter: blur(10px);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: 1.2rem;
    pointer-events: auto;
    z-index: 100;
}

/* --- Loading States --- */
.loader {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    opacity: 0.3;
}

/* --- Animations --- */
@keyframes fadeInSlide {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.ui-overlay > * {
    animation: fadeInSlide 0.8s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

.ui-overlay h2 { animation-delay: 0.1s; }
.ui-overlay p { animation-delay: 0.2s; }