/* css/styles.css */
@import url('https://fonts.googleapis.com/css2?family=Roboto:wght@300;400;500;700&display=swap');
@import url('https://fonts.googleapis.com/icon?family=Material+Icons');

/* Material Design Color Variables */
:root {
    --primary: #0F2C59;
    --primary-50: #f0f3f8;
    --primary-100: #d6e1ee;
    --primary-500: #0F2C59;
    --primary-600: #0a2549;
    --primary-700: #081e39;
    
    --accent: #009F9D;
    --accent-50: #e6f7f7;
    --accent-100: #b3ebea;
    --accent-500: #009F9D;
    --accent-600: #008280;
    --accent-700: #006663;
    
    --neutral-25: #FEFEFE;
    --neutral-50: #F8F9FA;
    --neutral-100: #F1F3F4;
    --neutral-200: #E8EAED;
    --neutral-300: #DADCE0;
    --neutral-400: #BDC1C6;
    --neutral-500: #9AA0A6;
    --neutral-600: #80868B;
    --neutral-700: #5F6368;
    --neutral-800: #2D3748;
    --neutral-900: #1F2937;
    
    --premium: #D2C1A7;
    --premium-50: #fbf9f6;
    --premium-100: #f4efe6;
    --premium-500: #D2C1A7;
    --premium-600: #c4b095;
    --premium-700: #b69f83;
    
    --data: #5A7B9E;
    --data-50: #f2f5f9;
    --data-100: #e1e9f2;
    --data-500: #5A7B9E;
    --data-600: #4d6a87;
    --data-700: #405970;
    
    --success: #22c55e;
    --warning: #f59e0b;
    --error: #ef4444;
}

/* Material Design Shadows */
.shadow-material-1 { box-shadow: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24); }
.shadow-material-2 { box-shadow: 0 3px 6px rgba(0,0,0,0.16), 0 3px 6px rgba(0,0,0,0.23); }
.shadow-material-3 { box-shadow: 0 10px 20px rgba(0,0,0,0.19), 0 6px 6px rgba(0,0,0,0.23); }
.shadow-material-4 { box-shadow: 0 14px 28px rgba(0,0,0,0.25), 0 10px 10px rgba(0,0,0,0.22); }
.shadow-material-5 { box-shadow: 0 19px 38px rgba(0,0,0,0.30), 0 15px 12px rgba(0,0,0,0.22); }

/* Material Design Typography */
.headline-4 { font-size: 1.75rem; font-weight: 400; line-height: 1.235; letter-spacing: 0.25px; }
.headline-6 { font-size: 1.125rem; font-weight: 500; line-height: 1.6; letter-spacing: 0.15px; }
.subtitle-1 { font-size: 1rem; font-weight: 400; line-height: 1.75; letter-spacing: 0.15px; }
.body-1 { font-size: 1rem; font-weight: 400; line-height: 1.5; letter-spacing: 0.5px; }
.button-text { font-size: 0.875rem; font-weight: 500; line-height: 1.75; letter-spacing: 1.25px; text-transform: uppercase; }
.caption { font-size: 0.75rem; font-weight: 400; line-height: 1.66; letter-spacing: 0.4px; }

@media (min-width: 768px) {
    .headline-4 { font-size: 2.125rem; }
    .headline-6 { font-size: 1.25rem; }
}

/* Material Design Components */
.material-card {
    transition: box-shadow 0.28s cubic-bezier(0.4, 0.0, 0.2, 1), transform 0.15s cubic-bezier(0.4, 0.0, 0.2, 1);
    background-color: white;
    border: 1px solid var(--neutral-300);
    border-radius: 12px;
}

.material-card:hover {
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
    transform: translateY(-2px);
}

.dark .material-card {
    background-color: var(--neutral-800);
    border-color: var(--neutral-600);
}

.dark .material-card:hover {
    box-shadow: 0 8px 25px rgba(0,0,0,0.3);
}

.material-button {
    transition: all 0.15s cubic-bezier(0.4, 0.0, 0.2, 1);
    position: relative;
    overflow: hidden;
    min-height: 44px;
    min-width: 44px;
}

.material-button:active {
    transform: scale(0.98);
}

/* Navigation Buttons */
.nav-btn {
    color: var(--neutral-600);
    padding: 8px 16px;
    border-radius: 8px;
    transition: all 0.15s cubic-bezier(0.4, 0.0, 0.2, 1);
    font-size: 0.875rem;
    font-weight: 500;
    letter-spacing: 1.25px;
    text-transform: uppercase;
}

.nav-btn:hover {
    color: var(--primary);
    background-color: var(--neutral-100);
}

.dark .nav-btn {
    color: var(--neutral-400);
}

.dark .nav-btn:hover {
    background-color: var(--neutral-700);
}

.nav-btn.active {
    color: var(--primary);
    background-color: rgba(15, 44, 89, 0.1);
    font-weight: 500;
}

/* Back Button */
.back-btn {
    color: var(--primary);
    margin-bottom: 16px;
    transition: color 0.15s cubic-bezier(0.4, 0.0, 0.2, 1);
    cursor: pointer;
}

.back-btn:hover {
    color: var(--primary-600);
}

/* Primary Button */
.primary-btn {
    background-color: var(--primary);
    color: white;
    padding: 8px 16px;
    border-radius: 8px;
    transition: all 0.15s cubic-bezier(0.4, 0.0, 0.2, 1);
    font-size: 0.875rem;
    font-weight: 500;
    letter-spacing: 1.25px;
    text-transform: uppercase;
    min-height: 44px;
}

.primary-btn:hover {
    background-color: var(--primary-600);
}

.primary-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* Secondary Button */
.secondary-btn {
    background-color: var(--neutral-100);
    color: var(--neutral-600);
    padding: 8px 16px;
    border-radius: 8px;
    transition: all 0.15s cubic-bezier(0.4, 0.0, 0.2, 1);
    font-size: 0.875rem;
    font-weight: 500;
    letter-spacing: 1.25px;
    text-transform: uppercase;
    min-height: 44px;
}

.secondary-btn:hover {
    background-color: var(--neutral-200);
}

.secondary-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.dark .secondary-btn {
    background-color: var(--neutral-700);
    color: var(--neutral-400);
}

.dark .secondary-btn:hover {
    background-color: var(--neutral-600);
}

/* Question Container */
.question-container {
    background-color: white;
    border: 1px solid var(--neutral-300);
    border-radius: 12px;
    padding: 24px;
    margin-bottom: 24px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);
}

.dark .question-container {
    background-color: var(--neutral-800);
    border-color: var(--neutral-600);
}

/* Tutor Container */
.tutor-container {
    background-color: white;
    border: 1px solid var(--neutral-300);
    border-radius: 12px;
    padding: 24px;
    margin-bottom: 16px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);
}

.dark .tutor-container {
    background-color: var(--neutral-800);
    border-color: var(--neutral-600);
}

/* Chat Area */
.chat-area {
    max-height: 384px;
    overflow-y: auto;
    margin-bottom: 16px;
    padding: 4px;
}

.chat-area > * + * {
    margin-top: 16px;
}

/* Chat Input */
.chat-input {
    flex: 1;
    padding: 12px 16px;
    font-size: 1rem;
    border: 1px solid var(--neutral-300);
    border-radius: 8px;
    background-color: white;
    transition: all 0.15s cubic-bezier(0.4, 0.0, 0.2, 1);
    min-height: 44px;
}

.chat-input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 2px rgba(15, 44, 89, 0.2);
}

.dark .chat-input {
    background-color: var(--neutral-700);
    border-color: var(--neutral-600);
    color: white;
}

/* Stats Card */
.stats-card {
    background-color: white;
    border: 1px solid var(--neutral-300);
    border-radius: 12px;
    padding: 24px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);
}

.dark .stats-card {
    background-color: var(--neutral-800);
    border-color: var(--neutral-600);
}

/* Modal */
.modal {
    position: fixed;
    inset: 0;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 50;
}

.modal-content {
    background-color: white;
    padding: 24px;
    border-radius: 12px;
    box-shadow: 0 10px 20px rgba(0,0,0,0.19), 0 6px 6px rgba(0,0,0,0.23);
    max-width: 384px;
    width: 100%;
    margin: 16px;
}

.dark .modal-content {
    background-color: var(--neutral-800);
}

/* Spinner */
.spinner {
    animation: spin 1s linear infinite;
    border-radius: 50%;
    height: 24px;
    width: 24px;
    border: 2px solid var(--neutral-300);
    border-top-color: var(--primary);
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Subject Card */
.subject-card {
    color: white;
    padding: 24px;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.28s cubic-bezier(0.4, 0.0, 0.2, 1);
    box-shadow: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);
}

.subject-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

/* Topic Card */
.topic-card {
    background-color: white;
    border: 1px solid var(--neutral-300);
    padding: 24px;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.28s cubic-bezier(0.4, 0.0, 0.2, 1);
    box-shadow: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);
}

.topic-card:hover {
    background-color: var(--neutral-50);
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.dark .topic-card {
    background-color: var(--neutral-800);
    border-color: var(--neutral-600);
}

.dark .topic-card:hover {
    background-color: var(--neutral-700);
}

/* Option Label */
.option-label {
    display: flex;
    align-items: center;
    padding: 12px;
    background-color: white;
    border: 1px solid var(--neutral-200);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.15s cubic-bezier(0.4, 0.0, 0.2, 1);
    margin-bottom: 8px;
}

.option-label:hover {
    background-color: var(--neutral-50);
    border-color: var(--primary);
}

.option-label input[type="radio"] {
    margin-right: 12px;
    accent-color: var(--primary);
}

.dark .option-label {
    background-color: var(--neutral-700);
    border-color: var(--neutral-600);
    color: white;
}

.dark .option-label:hover {
    background-color: var(--neutral-600);
}

/* Animations */
.fade-in {
    animation: fadeIn 0.6s cubic-bezier(0.4, 0.0, 0.2, 1);
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(16px); }
    to { opacity: 1; transform: translateY(0); }
}

.stagger-animation {
    animation: fadeInStagger 0.6s cubic-bezier(0.4, 0.0, 0.2, 1) forwards;
    opacity: 0;
}

.stagger-animation:nth-child(1) { animation-delay: 0.1s; }
.stagger-animation:nth-child(2) { animation-delay: 0.2s; }
.stagger-animation:nth-child(3) { animation-delay: 0.3s; }
.stagger-animation:nth-child(4) { animation-delay: 0.4s; }

@keyframes fadeInStagger {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Touch targets */
.touch-target {
    min-height: 44px;
    min-width: 44px;
}

/* Color utilities */
.text-primary { color: var(--primary); }
.text-primary-600 { color: var(--primary-600); }
.text-accent { color: var(--accent); }
.text-neutral-400 { color: var(--neutral-400); }
.text-neutral-600 { color: var(--neutral-600); }
.text-neutral-700 { color: var(--neutral-700); }
.text-neutral-800 { color: var(--neutral-800); }

.bg-primary { background-color: var(--primary); }
.bg-primary-600 { background-color: var(--primary-600); }
.bg-accent { background-color: var(--accent); }
.bg-data-500 { background-color: var(--data-500); }
.bg-data-600 { background-color: var(--data-600); }
.bg-warning { background-color: var(--warning); }
.bg-success { background-color: var(--success); }
.bg-error { background-color: var(--error); }

.bg-neutral-50 { background-color: var(--neutral-50); }
.bg-neutral-100 { background-color: var(--neutral-100); }
.bg-neutral-800 { background-color: var(--neutral-800); }
.bg-neutral-900 { background-color: var(--neutral-900); }

/* Dark mode text colors */
.dark .text-neutral-600 { color: var(--neutral-400); }
.dark .text-neutral-700 { color: var(--neutral-300); }
.dark .text-neutral-800 { color: white; }