/* Base Variables and Colors */
:root {
    --bg-color: #0f172a;
    --card-bg: rgba(30, 41, 59, 0.7);
    --card-border: rgba(255, 255, 255, 0.1);
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --primary: #3b82f6;
    --primary-hover: #2563eb;
    --accent: #8b5cf6;
    --error: #ef4444;
    --success: #10b981;
    --shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.5);
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    /* Soft background gradient */
    background: radial-gradient(circle at 15% 50%, rgba(59, 130, 246, 0.15), transparent 25%),
                radial-gradient(circle at 85% 30%, rgba(139, 92, 246, 0.15), transparent 25%),
                var(--bg-color);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.header {
    padding: 40px 0;
    text-align: center;
}

.header h1 {
    font-size: 3rem;
    font-weight: 700;
    background: linear-gradient(to right, var(--primary), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 10px;
}

.header p {
    color: var(--text-muted);
    font-size: 1.1rem;
}

/* Main Content Area */
main {
    flex: 1;
    padding: 20px 0;
}

/* Grid Layout for Cards */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

/* Glassmorphism Cards */
.card {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 16px;
    padding: 30px;
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    box-shadow: var(--shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 40px -10px rgba(0, 0, 0, 0.7);
    border-color: rgba(255, 255, 255, 0.2);
}

.card h2 {
    font-size: 1.5rem;
    margin-bottom: 10px;
}

.card p {
    color: var(--text-muted);
    margin-bottom: 25px;
    font-size: 0.95rem;
}

/* Forms and Inputs */
.conversion-form {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.input-group label {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-muted);
}

.input-group input {
    background: rgba(15, 23, 42, 0.5);
    border: 1px solid var(--card-border);
    color: var(--text-main);
    padding: 12px 16px;
    border-radius: 8px;
    font-family: inherit;
    font-size: 1rem;
    transition: border-color 0.3s, box-shadow 0.3s;
}

.input-group input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.2);
}

/* Drag and Drop Area */
.file-drop-area {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    gap: 10px;
    padding: 30px;
    border: 2px dashed var(--card-border);
    border-radius: 12px;
    background: rgba(255, 255, 255, 0.02);
    transition: all 0.3s ease;
    cursor: pointer;
}

.file-drop-area.is-active {
    border-color: var(--primary);
    background: rgba(59, 130, 246, 0.05);
}

.fake-btn {
    background-color: rgba(255, 255, 255, 0.1);
    border: 1px solid var(--card-border);
    padding: 8px 16px;
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 500;
    transition: background 0.2s;
}

.file-drop-area:hover .fake-btn {
    background-color: rgba(255, 255, 255, 0.15);
}

.file-msg {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.file-input {
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    width: 100%;
    cursor: pointer;
    opacity: 0;
}

/* Submit Button */
.submit-btn {
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: white;
    border: none;
    padding: 14px 24px;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s, opacity 0.2s;
    font-family: inherit;
}

.submit-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px -5px rgba(59, 130, 246, 0.5);
}

.submit-btn:active {
    transform: translateY(0);
}

/* Flash Messages */
.flash-messages {
    margin-bottom: 30px;
}

.flash-message {
    padding: 15px 20px;
    border-radius: 8px;
    margin-bottom: 10px;
    font-weight: 500;
}

.flash-message.error {
    background-color: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.3);
    color: #fca5a5;
}

/* Footer */
.footer {
    padding: 30px 0;
    text-align: center;
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-top: 40px;
}