:root {
    --primary-color: #1d4ed8;
    --primary-light: #eff6ff;
    --bg-color: #f1f5f9;
    --card-bg: rgba(255, 255, 255, 0.95);
    --text-main: #0f172a;
    --success: #10b981;
    --danger: #ef4444;
    --digital-bg: #022c22;
    --digital-text: #10b981;
    --border: #e2e8f0;
    --shadow: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    background: linear-gradient(135deg, #e0e7ff 0%, #f8fafc 100%);
    color: var(--text-main);
    line-height: 1.5;
    min-height: 100vh;
}

.app-container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 2rem;
}

.app-header {
    margin-bottom: 2.5rem;
    padding-bottom: 1.5rem;
    border-bottom: 2px solid var(--primary-light);
    text-align: center;
}

.header-title {
    font-size: 2.5rem;
    font-weight: 800;
    color: #1e293b;
    letter-spacing: -0.025em;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 0.75rem;
}

.header-subtitle {
    color: #475569;
    font-size: 1.1rem;
    margin-top: 0.75rem;
}

.simulation-layout {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-bottom: 2rem;
}

.card {
    background: var(--card-bg);
    border: 1px solid rgba(255, 255, 255, 0.5);
    padding: 2.5rem;
    border-radius: 16px;
    box-shadow: var(--shadow);
    backdrop-filter: blur(10px);
}

.left-panel {
    flex: 1;
    max-width: 500px;
}

.right-panel {
    flex: 1;
    max-width: 400px;
}

.panel-title {
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    color: var(--primary-color);
    text-decoration: underline;
    text-align: center;
    display: none; /* Hidden because original UI didn't have these titles */
}

/* Let's show specific titles matching the image */
.setting-label {
    display: block;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--primary-color);
    text-decoration: underline;
    text-align: center;
}

.radio-group {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    justify-content: center;
    font-weight: bold;
}

.radio-group label {
    display: flex;
    align-items: center;
    gap: 0.25rem;
    font-size: 1rem;
    cursor: pointer;
}

/* Disc Visualizer */
.visualizer {
    display: flex;
    flex-direction: column;
    align-items: center;
    margin: 3rem 0;
}

.disc-container {
    width: 250px;
    height: 250px;
    background-color: #ededed;
    border-radius: 50%;
    position: relative;
    margin-bottom: 1rem;
}

.disc {
    width: 100%;
    height: 100%;
    border-radius: 50%;
    position: relative;
    transform: rotate(0deg);
    transform-origin: center center;
}

.disc-center {
    width: 30px;
    height: 30px;
    background-color: #000;
    border-radius: 50%;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    z-index: 10;
}

.needle {
    width: 6px;
    height: 110px;
    background-color: #000;
    position: absolute;
    top: 50%;
    left: calc(50% - 3px);
    transform-origin: top center;
    border-radius: 3px;
    z-index: 5;
}

.moving-contact {
    width: 12px;
    height: 12px;
    background-color: #1e88e5; /* Blue dot on needle */
    border-radius: 50%;
    position: absolute;
    top: calc(50% + 90px);
    left: calc(50% - 6px);
    z-index: 6;
}

.fixed-contact {
    width: 14px;
    height: 14px;
    background-color: #1e88e5; /* Blue square */
    position: absolute;
    top: 50%;
    right: 20px;
    transform: translateY(-50%);
}

.indicator {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    border: 2px solid #ff7b7b;
    background-color: transparent;
    transition: background-color 0.1s ease;
}

.indicator.tripped {
    background-color: var(--danger);
    border-color: var(--danger);
}

.indicator-label {
    margin-top: 0.5rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: underline;
}

/* Time Setting */
.tms-controls {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
}

.tms-btn {
    width: 60px;
    height: 40px;
    border: 1px solid var(--border);
    background-color: #f8fafc;
    font-size: 1.5rem;
    font-weight: bold;
    cursor: pointer;
    border-radius: 8px;
    color: var(--primary-color);
    transition: all 0.2s ease;
}

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

.tms-btn:active {
    transform: scale(0.95);
}

.tms-value {
    display: none; 
}

/* Instrumentation Panel */
.display-group {
    margin-bottom: 2rem;
    text-align: center;
}

.display-label {
    display: block;
    font-weight: 700;
    color: var(--text-main);
    margin-bottom: 0.75rem;
    font-size: 1.1rem;
}

.digital-display {
    background-color: var(--digital-bg);
    color: var(--digital-text);
    font-family: 'Courier New', Courier, monospace;
    font-size: 1.5rem;
    font-weight: bold;
    padding: 0.75rem;
    border-radius: 8px;
    border: 2px solid #064e3b;
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.5);
    margin: 0 auto;
    width: 80%;
    text-align: center;
    letter-spacing: 2px;
}

.control-actions {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-top: 2.5rem;
    align-items: center;
}

.action-btn {
    width: 80%;
    padding: 1rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: 0 4px 6px -1px rgba(29, 78, 216, 0.2);
}

.action-btn:hover {
    background: #1e40af;
    transform: translateY(-1px);
    box-shadow: 0 6px 8px -1px rgba(29, 78, 216, 0.3);
}

.action-btn:active {
    transform: translateY(1px);
    box-shadow: 0 2px 4px -1px rgba(29, 78, 216, 0.2);
}

.reset-btn {
    background: #fef2f2;
    color: var(--danger);
    border: 1px solid #fecaca;
    box-shadow: none;
}

.reset-btn:hover {
    background: #fee2e2;
    border-color: #fca5a5;
    box-shadow: none;
}

/* Video Section */
.video-section {
    margin-top: 2rem;
    max-width: 1000px;
    margin-left: auto;
    margin-right: auto;
}

.video-section .panel-title {
    display: block;
    font-size: 2.5rem;
    color: #000;
    text-decoration: underline;
    text-align: left;
    margin-bottom: 2rem;
}

.video-grid {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.video-item {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.video-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: #000;
}

.video-wrapper {
    background: #000;
    border-radius: 8px;
    overflow: hidden;
    position: relative;
    padding-bottom: 56.25%; /* 16:9 aspect ratio */
    box-shadow: var(--shadow);
}

.video-wrapper video {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
    outline: none;
}