/* ============================================
   NOTENRECHNER - Modern Grade Converter
   ============================================ */

/* CSS Variables */
:root {
    /* Colors */
    --color-bg-dark: #0f0f1a;
    --color-bg-card: rgba(30, 30, 50, 0.85);
    --color-bg-card-hover: rgba(40, 40, 70, 0.9);

    --color-primary: #7c3aed;
    --color-primary-light: #a78bfa;
    --color-primary-dark: #5b21b6;

    --color-accent: #06b6d4;
    --color-accent-light: #67e8f9;

    --color-success: #10b981;
    --color-warning: #f59e0b;
    --color-danger: #ef4444;

    --color-text-primary: #f8fafc;
    --color-text-secondary: #94a3b8;
    --color-text-muted: #64748b;

    /* Grade Colors */
    --grade-excellent: #10b981;
    --grade-good: #22c55e;
    --grade-satisfactory: #84cc16;
    --grade-adequate: #eab308;
    --grade-poor: #f97316;
    --grade-fail: #ef4444;

    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;

    /* Border Radius */
    --radius-sm: 0.5rem;
    --radius-md: 0.75rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.15);
    --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.2);
    --shadow-glow: 0 0 40px rgba(124, 58, 237, 0.3);

    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-md: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.5rem;
    --font-size-2xl: 2rem;
    --font-size-3xl: 3rem;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
    --transition-slow: 400ms ease;
}

/* Reset & Base */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    background: var(--color-bg-dark);
    color: var(--color-text-primary);
    min-height: 100vh;
    line-height: 1.6;
    overflow-x: hidden;
}

/* App Container */
.app-container {
    position: relative;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: var(--space-lg);
}

/* Background Animation */
.background-shapes {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    z-index: -1;
    pointer-events: none;
}

.shape {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.5;
    animation: float 20s ease-in-out infinite;
}

.shape-1 {
    width: 400px;
    height: 400px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    top: -100px;
    right: -100px;
    animation-delay: 0s;
}

.shape-2 {
    width: 300px;
    height: 300px;
    background: linear-gradient(135deg, var(--color-accent), var(--color-success));
    bottom: -50px;
    left: -50px;
    animation-delay: -7s;
}

.shape-3 {
    width: 250px;
    height: 250px;
    background: linear-gradient(135deg, var(--color-primary-light), var(--color-primary));
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    animation-delay: -14s;
}

@keyframes float {

    0%,
    100% {
        transform: translate(0, 0) scale(1);
    }

    25% {
        transform: translate(30px, -30px) scale(1.05);
    }

    50% {
        transform: translate(-20px, 20px) scale(0.95);
    }

    75% {
        transform: translate(20px, 30px) scale(1.02);
    }
}

/* Header */
.header {
    text-align: center;
    margin-bottom: var(--space-xl);
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    margin-bottom: var(--space-xs);
}

.logo-icon {
    font-size: var(--font-size-2xl);
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {

    0%,
    100% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.1);
    }
}

.logo h1 {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    background: linear-gradient(135deg, var(--color-text-primary), var(--color-primary-light));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    color: var(--color-text-secondary);
    font-size: var(--font-size-md);
    font-weight: 300;
}

/* Main Content */
.main-content {
    width: 100%;
    max-width: 500px;
    display: flex;
    flex-direction: column;
    gap: var(--space-lg);
}

/* Converter Card */
.converter-card {
    background: var(--color-bg-card);
    border-radius: var(--radius-xl);
    padding: var(--space-xl);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
    transition: transform var(--transition-normal);
}

.converter-card:hover {
    transform: translateY(-2px);
}

/* Mode Toggle */
.mode-toggle {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-sm);
    margin-bottom: var(--space-xl);
    background: rgba(0, 0, 0, 0.3);
    padding: var(--space-xs);
    border-radius: var(--radius-lg);
}

.mode-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    padding: var(--space-md);
    border: none;
    border-radius: var(--radius-md);
    background: transparent;
    color: var(--color-text-secondary);
    font-family: inherit;
    font-size: var(--font-size-sm);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-normal);
}

.mode-btn:hover {
    color: var(--color-text-primary);
    background: rgba(255, 255, 255, 0.05);
}

.mode-btn.active {
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    color: white;
    box-shadow: 0 4px 15px rgba(124, 58, 237, 0.4);
}

.mode-icon {
    font-size: var(--font-size-lg);
}

/* Input Section */
.input-section {
    margin-bottom: var(--space-xl);
}

.input-wrapper {
    position: relative;
}

.input-wrapper label {
    display: block;
    margin-bottom: var(--space-sm);
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    font-weight: 500;
}

.input-wrapper input {
    width: 100%;
    padding: var(--space-lg) var(--space-md);
    background: rgba(0, 0, 0, 0.3);
    border: 2px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-md);
    color: var(--color-text-primary);
    font-family: inherit;
    font-size: var(--font-size-2xl);
    font-weight: 600;
    text-align: center;
    transition: all var(--transition-normal);
    -moz-appearance: textfield;
}

.input-wrapper input::-webkit-outer-spin-button,
.input-wrapper input::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

.input-wrapper input::placeholder {
    color: var(--color-text-muted);
    opacity: 0.5;
}

.input-wrapper input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 4px rgba(124, 58, 237, 0.2);
}

.input-decoration {
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
    border-radius: var(--radius-full);
    transition: width var(--transition-normal);
}

.input-wrapper input:focus+.input-decoration {
    width: 50%;
}

/* Result Section */
.result-section {
    text-align: center;
    padding: var(--space-xl);
    background: rgba(0, 0, 0, 0.2);
    border-radius: var(--radius-lg);
    margin-bottom: var(--space-lg);
}

.result-label {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: var(--space-sm);
}

.result-value {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    color: var(--color-text-primary);
    transition: all var(--transition-normal);
}

.result-value.grade-excellent {
    color: var(--grade-excellent);
}

.result-value.grade-good {
    color: var(--grade-good);
}

.result-value.grade-satisfactory {
    color: var(--grade-satisfactory);
}

.result-value.grade-adequate {
    color: var(--grade-adequate);
}

.result-value.grade-poor {
    color: var(--grade-poor);
}

.result-value.grade-fail {
    color: var(--grade-fail);
}

.result-details {
    margin-top: var(--space-sm);
    font-size: var(--font-size-md);
    color: var(--color-text-secondary);
    min-height: 1.5em;
}

/* Quick Reference */
.quick-reference {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: var(--space-lg);
}

.reference-toggle {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    padding: var(--space-md);
    background: rgba(0, 0, 0, 0.2);
    border: 1px solid rgba(255, 255, 255, 0.05);
    border-radius: var(--radius-md);
    color: var(--color-text-secondary);
    font-family: inherit;
    font-size: var(--font-size-sm);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-normal);
}

.reference-toggle:hover {
    background: rgba(0, 0, 0, 0.3);
    color: var(--color-text-primary);
}

.toggle-icon {
    transition: transform var(--transition-normal);
}

.reference-toggle.active .toggle-icon {
    transform: rotate(180deg);
}

.reference-table-wrapper {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-slow);
}

.reference-table-wrapper.open {
    max-height: 900px;
}

.reference-table {
    width: 100%;
    margin-top: var(--space-md);
    border-collapse: collapse;
    font-size: var(--font-size-sm);
}

.reference-table th,
.reference-table td {
    padding: var(--space-sm) var(--space-md);
    text-align: center;
}

.reference-table th {
    color: var(--color-text-secondary);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-size: var(--font-size-xs);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.reference-table td {
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.reference-table tr:last-child td {
    border-bottom: none;
}

.reference-table tr.grade-excellent td:first-child {
    color: var(--grade-excellent);
    font-weight: 600;
}

.reference-table tr.grade-good td:first-child {
    color: var(--grade-good);
    font-weight: 600;
}

.reference-table tr.grade-satisfactory td:first-child {
    color: var(--grade-satisfactory);
    font-weight: 600;
}

.reference-table tr.grade-adequate td:first-child {
    color: var(--grade-adequate);
    font-weight: 600;
}

.reference-table tr.grade-poor td:first-child {
    color: var(--grade-poor);
    font-weight: 600;
}

.reference-table tr.grade-fail td:first-child {
    color: var(--grade-fail);
    font-weight: 600;
}

/* Formula Card */
.formula-card {
    background: var(--color-bg-card);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.formula-card h2 {
    font-size: var(--font-size-md);
    font-weight: 600;
    margin-bottom: var(--space-md);
    color: var(--color-text-primary);
}

.formulas {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

.formula {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    flex-wrap: wrap;
}

.formula-label {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    min-width: 120px;
}

.formula code {
    background: rgba(0, 0, 0, 0.3);
    padding: var(--space-xs) var(--space-sm);
    border-radius: var(--radius-sm);
    font-family: 'SF Mono', 'Fira Code', monospace;
    font-size: var(--font-size-sm);
    color: var(--color-accent-light);
}

/* Footer */
.footer {
    margin-top: auto;
    padding-top: var(--space-xl);
    text-align: center;
}

.footer p {
    color: var(--color-text-muted);
    font-size: var(--font-size-xs);
}

/* Responsive */
@media (max-width: 600px) {
    .app-container {
        padding: var(--space-md);
    }

    .converter-card {
        padding: var(--space-lg);
    }

    .mode-btn {
        padding: var(--space-sm);
        font-size: var(--font-size-xs);
        flex-direction: column;
        gap: var(--space-xs);
    }

    .mode-icon {
        font-size: var(--font-size-xl);
    }

    .input-wrapper input {
        font-size: var(--font-size-xl);
        padding: var(--space-md);
    }

    .result-value {
        font-size: var(--font-size-2xl);
    }

    .formula {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--space-xs);
    }

    .formula-label {
        min-width: auto;
    }
}

/* Animations */
@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

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

.converter-card,
.formula-card {
    animation: slideIn 0.6s ease-out;
}

.formula-card {
    animation-delay: 0.2s;
    animation-fill-mode: both;
}