:root {
    --bg-color: #030712;
    --text-color: #f8fafc;
    --primary-color: #38bdf8;
    --primary-hover: #0ea5e9;
    --secondary-color: #1e293b;
    --accent-color: #06b6d4;
    --glass-bg: rgba(17, 24, 39, 0.9);
    --glass-border: rgba(56, 189, 248, 0.2);
    --success-color: #10b981;
    --error-color: #ef4444;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    background-image:
        radial-gradient(circle at 10% 20%, rgba(56, 189, 248, 0.15) 0%, transparent 40%),
        radial-gradient(circle at 90% 80%, rgba(14, 165, 233, 0.15) 0%, transparent 40%);
    color: var(--text-color);
    height: 100vh;
    overflow: hidden;
    /* Prevent body scroll */
    display: flex;
    justify-content: center;
    align-items: center;
}

.container {
    background: var(--glass-bg);
    backdrop-filter: blur(25px);
    border: 1px solid var(--glass-border);
    border-radius: 20px;
    width: 98%;
    max-width: 1600px;
    /* Use almost full width */
    height: 96vh;
    /* Use almost full height */
    display: flex;
    flex-direction: column;
    box-shadow: 0 0 80px rgba(56, 189, 248, 0.15);
    position: relative;
    overflow: hidden;
}

/* Header */
header {
    padding: 20px 60px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: rgba(0, 0, 0, 0.2);
    flex-shrink: 0;
    /* Keep header fixed size */
}

.logo-img {
    height: 70px;
    /* Slightly smaller to save vertical space */
    vertical-align: middle;
}

.progress-bar-container {
    width: 400px;
    height: 8px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 4px;
    overflow: hidden;
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
    width: 0%;
    transition: width 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 0 15px rgba(56, 189, 248, 0.6);
}

/* Main Content */
main {
    flex: 1;
    padding: 0 80px;
    /* Remove vertical padding, rely on centering */
    display: flex;
    flex-direction: column;
    justify-content: center;
    /* Vertically center content */
    align-items: flex-start;
    position: relative;
    overflow-y: auto;
    /* Scroll only if absolutely necessary */
}

/* Start Page Specifics */
main>div[style*="text-align: center"] {
    width: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    /* Fill the main area */
}

h1 {
    font-size: 2.8rem;
    margin-bottom: 1.5rem;
    color: white;
    font-weight: 800;
    letter-spacing: -0.02em;
    background: linear-gradient(to right, #fff, #bae6fd);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    line-height: 1.2;
    padding-bottom: 5px;
}

h2 {
    font-size: 1.6rem;
    margin: 1.5rem 0 1rem 0;
    color: var(--primary-color);
}

h3 {
    font-size: 1.3rem;
    margin: 0 0 1rem 0;
    color: #e2e8f0;
    font-weight: 600;
}

p {
    font-size: 1.15rem;
    line-height: 1.6;
    margin-bottom: 1.5rem;
    color: #cbd5e1;
    max-width: 1300px;
}

/* Compact Lists to fit on screen */
ul {
    list-style: none;
    margin-bottom: 2rem;
    margin-top: 0.5rem;
}

li {
    margin-bottom: 0.8rem;
    /* Reduced margin to fit better */
    font-size: 1.1rem;
    color: #e2e8f0;
    padding-left: 2rem;
    position: relative;
    line-height: 1.5;
}

ul li::before {
    content: "•";
    color: var(--primary-color);
    position: absolute;
    left: 0;
    font-size: 1.5rem;
    line-height: 1;
    top: -3px;
}

ol {
    list-style: decimal;
    margin-bottom: 2rem;
    margin-top: 0.5rem;
    padding-left: 2rem;
    color: #e2e8f0;
}

ol li {
    padding-left: 0.5rem;
}

ol li::before {
    display: none;
}

.card {
    background: linear-gradient(180deg, rgba(255, 255, 255, 0.04) 0%, rgba(255, 255, 255, 0.01) 100%);
    padding: 30px;
    /* Slightly reduced padding */
    border-radius: 16px;
    border: 1px solid rgba(255, 255, 255, 0.08);
    margin: 20px 0;
    width: 100%;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
}

.highlight {
    color: var(--primary-color);
    font-weight: 600;
}

/* Buttons */
footer {
    padding: 25px 60px;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: rgba(0, 0, 0, 0.2);
    flex-shrink: 0;
}

.nav-btn {
    padding: 15px 40px;
    border-radius: 12px;
    border: none;
    font-weight: 600;
    font-size: 1.1rem;
    cursor: pointer;
    transition: all 0.2s;
    font-family: 'Inter', sans-serif;
}

.nav-btn.primary {
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    color: #0f172a;
    box-shadow: 0 0 20px rgba(56, 189, 248, 0.3);
}

.nav-btn.primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 0 30px rgba(56, 189, 248, 0.5);
}

.nav-btn.secondary {
    background: transparent;
    color: #94a3b8;
    border: 1px solid #334155;
}

.nav-btn.secondary:hover:not(:disabled) {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.nav-btn:disabled {
    opacity: 0.3;
    cursor: not-allowed;
    transform: none;
}

/* Quiz Styles */
.quiz-option {
    display: flex;
    align-items: center;
    width: 100%;
    padding: 20px 30px;
    margin: 12px 0;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 14px;
    color: white;
    text-align: left;
    cursor: pointer;
    transition: all 0.2s;
    font-size: 1.1rem;
}

.quiz-option:hover {
    background: rgba(56, 189, 248, 0.1);
    border-color: var(--primary-color);
    transform: translateX(5px);
}

.quiz-option.correct {
    background: rgba(16, 185, 129, 0.2);
    border-color: #10b981;
}

.quiz-option.wrong {
    background: rgba(239, 68, 68, 0.2);
    border-color: #ef4444;
}

.feedback-msg {
    margin-top: 20px;
    padding: 20px;
    border-radius: 12px;
    background: rgba(255, 255, 255, 0.05);
    display: none;
    font-size: 1.1rem;
    line-height: 1.6;
}

.feedback-msg.show {
    display: block;
    animation: fadeIn 0.3s ease;
}

.start-btn {
    font-size: 1.5rem;
    padding: 22px 60px;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    border: none;
    color: #0f172a;
    border-radius: 60px;
    cursor: pointer;
    margin-top: 40px;
    font-weight: 700;
    box-shadow: 0 0 25px rgba(56, 189, 248, 0.4);
    transition: transform 0.2s;
}

.start-btn:hover {
    transform: scale(1.05);
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Scrollbar (hidden but functional if needed) */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.2);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: rgba(255, 255, 255, 0.3);
}

/* Input Styles */
.name-input {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.2);
    color: white;
    padding: 15px 25px;
    font-size: 1.2rem;
    border-radius: 12px;
    width: 100%;
    max-width: 400px;
    margin-top: 30px;
    font-family: 'Inter', sans-serif;
    outline: none;
    transition: all 0.3s;
    text-align: center;
}

.name-input:focus {
    border-color: var(--primary-color);
    background: rgba(255, 255, 255, 0.1);
    box-shadow: 0 0 0 4px rgba(56, 189, 248, 0.1);
}

.name-input::placeholder {
    color: rgba(255, 255, 255, 0.4);
}