@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600&display=swap');

/* ============================== */
/* ROOT VARIABLES */
:root {
  --primary-color: #a0a0a0;      /* Linkler, soft gri ton */
  --secondary-color: #c0c0c0;    /* Hover / vurgu ton, hafif açık gri */
  --heading-color: #e5e5e5;      /* Başlıklar için kirli beyaz */
  --background-color: #121212;   /* Site arka planı */
  --text-color: #eee;            /* Normal metin */
  --text-muted: #aaa;            /* Metin alt ton */
  --header-bg: #1a1a1a;
  --footer-bg: #1a1a1a;
  --border-color: #333;
  --radius-small: 6px;
  --radius-medium: 12px;
  --radius-large: 16px;
  --transition-fast: 0.2s ease;
  --font-family-base: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
}

/* ============================== */
/* ACCESSIBILITY – SCREEN READER ONLY */
/* ============================== */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ============================== */
/* GLOBAL SETTINGS */
html {
  font-size: 15px;
  box-sizing: border-box;
}

*, *::before, *::after {
  box-sizing: inherit;
}

body {
  font-family: var(--font-family-base);
  margin: 0;
  background-color: var(--background-color);
  color: var(--text-color);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* Headings */
h1, h2, h3, h4, h5, h6 {
  margin: 0;
  font-weight: 500;
  color: var(--heading-color);
}

p {
  margin: 0 0 1em 0;
  color: var(--text-muted);
}

/* Tüm sayfalarda iki dil elementi başlangıçta gizli */
.lang-en,
.lang-tr {
  display: none; /* JS yüklenene kadar gizli */
}


/* ============================== */
/* LINKS */
a {
  color: var(--primary-color);
  text-decoration: none;
  padding: 2px 4px;
  border-radius: var(--radius-small);
  transition: opacity var(--transition-fast), background-color var(--transition-fast);
}

a:hover {
  opacity: 1;
  background-color: transparent;
  color: var(--secondary-color);
}

/* ============================== */
/* BUTTONS - BASE */
button {
  font-family: var(--font-family-base);
  cursor: pointer;
  border-radius: var(--radius-small);
  border: 1px solid var(--border-color);
  background-color: transparent;
  color: var(--text-color);
  padding: 6px 12px;
  transition: all var(--transition-fast);
  white-space: normal; /* uzun metinlerde satır kır */
}

button:hover {
  opacity: 0.85;
  background-color: rgba(255,255,255,0.05);
  color: var(--text-color);
  border-color: var(--secondary-color);
}

/* ============================== */
/* HEADER & FOOTER BASE */
header, footer {
  width: 100%;
  padding: 16px 32px;
  background-color: var(--header-bg);
}

footer {
  text-align: center;
  color: var(--text-muted);
  border-top: 1px solid var(--border-color);
}

/* ============================== */
/* RESPONSIVE GLOBAL SETTINGS */
@media (max-width: 768px) {
  html {
    font-size: 14px;
  }

  header, footer {
    padding: 12px 16px;
  }
}

@media (max-width: 480px) {
  html {
    font-size: 13px;
  }

  header, footer {
    padding: 10px 12px;
  }
}

/* ============================== */
/* GENERIC CONTENT SECTIONS */
.about-section {
  text-align: center;
  max-width: 700px;
  margin: 0 auto;
}

/* ============================== */
/* SOFT HOVER EFFECTS */
.header-link,
.site-title,
.exercise-card,
.option-btn,
.lang-btn {
  transition: opacity var(--transition-fast), background-color var(--transition-fast);
}

.header-link:hover,
.site-title:hover,
.exercise-card:hover,
.option-btn:hover,
.lang-btn:hover {
  opacity: 0.85;
  background-color: rgba(255,255,255,0.05);
  text-decoration: none;
  color: inherit;
}
/* OPTION BUTTON FOCUS */
.option-btn:focus {
  outline: 2px solid #f39c12;
  background-color: rgba(243, 156, 18, 0.1);
}