:root {
    /* Light Mode Colors */
    --bg-color-light: #f4f7f9;
    --card-bg-light: #ffffff;
    --text-color-light: #333333;
    --secondary-text-light: #666666;
    --border-color-light: #e0e0e0;
    --primary-color: #fdaaaa; /* A fresh primary color for both modes */
    --primary-hover-color: #fdaaa;
    --button-text-color: #ffffff;
    --progress-color: #fdaaaa;
    --timer-text-color: #333333;
    --active-stretch-bg: var(--primary-color);
    --active-stretch-text: white;
}

body.dark-mode {
    /* Dark Mode Colors */
    --bg-color-light: #121212;
    --card-bg-light: #1e1e1e;
    --text-color-light: #e0e0e0;
    --secondary-text-light: #b0b0b0;
    --border-color-light: #333333;
    --primary-color: #bb86fc;
    --primary-hover-color: #924ce0;
    --button-text-color: #121212;
    --progress-color: #bb86fc;
    --timer-text-color: #bb86fc;
    --active-stretch-bg: var(--primary-color);
    --active-stretch-text: white;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color-light);
    color: var(--text-color-light);
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    transition: background-color 0.3s, color 0.3s;
    overflow: auto;
}

.exercise-container {
    background-color: var(--card-bg-light);
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    padding: 30px;
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 95%;
    max-width: 800px;
    position: relative;
}

h1 {
    color: var(--primary-color);
    margin-bottom: 5px;
    font-size: 2.2em;
}

p {
    color: var(--secondary-text-light);
    margin-bottom: 20px;
    text-align: center;
    font-size: 1.1em;
}

.video-wrapper {
    width: 100%;
    aspect-ratio: 16 / 9;
    background-color: #000;
    border-radius: 10px;
    margin-bottom: 20px;
    overflow: hidden;
}

.video-wrapper video {
    width: 100%;
    height: 100%;
}

.timer-display {
    font-family: 'Roboto Mono', monospace;
    font-size: 4.5em;
    font-weight: 700;
    color: var(--timer-text-color);
    margin: 20px 0 10px;
    text-shadow: 0 0 15px rgba(187, 134, 252, 0.5); /* Updated shadow color */
    letter-spacing: 2px;
}

.current-stretch-name {
    font-size: 1.5em;
    font-weight: bold;
    text-align: center;
    margin-bottom: 20px;
    color: var(--primary-color);
}

.stretch-list-header {
    font-size: 1.3em;
    color: var(--text-color-light);
    margin: 30px 0 15px;
    width: 100%;
    text-align: left;
    padding-left: 20px;
    box-sizing: border-box;
}

.stretch-list {
    width: 100%;
    list-style: none;
    padding: 0;
    margin: 0 0 20px 0;
    text-align: left;
}

.stretch-list li {
    padding: 15px;
    background-color: var(--bg-color-light);
    border-radius: 8px;
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    gap: 15px;
    transition: background-color 0.2s, border-color 0.2s;
    border: 1px solid transparent;
}

.stretch-list li.active-stretch {
    border-color: var(--primary-color);
    box-shadow: 0 0 8px rgba(187, 134, 252, 0.3); /* Updated shadow color */
    background-color: var(--active-stretch-bg);
    color: var(--active-stretch-text);
}

.stretch-list li.active-stretch h4,
.stretch-list li.active-stretch p {
    color: var(--active-stretch-text);
}

.stretch-list li .stretch-number {
    font-size: 1.2em;
    font-weight: bold;
    color: var(--primary-color);
    min-width: 25px;
    text-align: center;
}

.stretch-list li.active-stretch .stretch-number {
    color: var(--active-stretch-text);
}

.stretch-list li h4 {
    margin: 0;
    font-size: 1.1em;
}

.stretch-list li p {
    margin: 0;
    font-size: 0.9em;
    color: var(--secondary-text-light);
}

.btn {
    padding: 12px 25px;
    border: none;
    border-radius: 25px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: bold;
    transition: background-color 0.2s, transform 0.1s;
    background-color: var(--primary-color);
    color: var(--button-text-color);
    display: flex;
    align-items: center;
    gap: 10px;
}

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

.theme-toggle {
    position: absolute;
    top: 20px;
    right: 20px;
    background: var(--card-bg-light);
    border: 1px solid var(--border-color-light);
    border-radius: 50%;
    width: 45px;
    height: 45px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: background-color 0.3s, border-color 0.3s, transform 0.2s;
    z-index: 101;
}

.theme-toggle .material-icons {
    font-size: 24px;
    color: var(--text-color-light);
    transition: color 0.3s;
}

.theme-toggle:hover {
    background-color: var(--bg-color-light);
    transform: scale(1.05);
}

/* Suggested Videos Section */
.suggested-videos {
    margin-top: 30px;
    width: 100%;
    display: none;
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.5s ease-out, transform 0.5s ease-out;
}

.suggested-videos.active {
    display: block;
    opacity: 1;
    transform: translateY(0);
}

.suggested-videos h2 {
    font-size: 1.5em;
    color: var(--primary-color);
    margin-bottom: 20px;
    text-align: center;
}

.suggested-videos-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    width: 100%;
}

.video-card {
    background-color: var(--bg-color-light);
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
}

.video-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.video-card .thumbnail {
    width: 100%;
    aspect-ratio: 16 / 9;
    object-fit: cover;
    display: block;
}

.video-card .video-info {
    padding: 15px;
}

.video-card .video-info h3 {
    margin: 0 0 5px;
    font-size: 1.1em;
    color: var(--text-color-light);
}

.video-card .video-info p {
    margin: 0;
    font-size: 0.9em;
    color: var(--secondary-text-light);
    text-align: left;
}